DE102010001576A1 - Applying a coating medium in two layers on surface of moving paper-, cardboard- or other fibrous material web in machine to produce and/or process the web with curtain applicator, by initially applying primer coat on surface of the web - Google Patents

Abstract

The method for applying a coating medium in two layers on a surface of a moving paper-, cardboard- or other fibrous material web (2) in a machine (3) for producing and/or processing the fibrous material web with a curtain applicator (6), which delivers the coating medium in the form of a single- or multi-layered curtain to the gravitational force following the fibrous material web, on which the coating medium applies itself as application layer, comprises initially applying a primer coat on the surface of the fibrous material web with the applicator. The method for applying a coating medium in two layers on a surface of a moving paper-, cardboard- or other fibrous material web (2) in a machine (3) for producing and/or processing the fibrous material web with a curtain applicator (6), which delivers the coating medium in the form of a single- or multi-layered curtain to the gravitational force following the fibrous material web, on which the coating medium applies itself as application layer, comprises initially applying a primer coat on the surface of the fibrous material web with the applicator, pressing the primer coat in the surface of the fibrous material web with a pressing element, where the fibrous material runs over a supporting surface during applying the primer coat, and then forming an outer coat by the coating layer applied with the curtain applicator without using intermediate drying. The primer coat forms a bonding layer and is applied in a quantity or a coating weight of 2-8 g/m 2>. The outer coat consists of pigment-containing coating color and is applied in a quantity or a coating weight of 12-22 g/m 2>. Independent claims are included for: (1) a corrugated paper web; and (2) a device for applying a coating medium in two layers on a surface a moving paper-, cardboard- or other fibrous material web in a machine for producing and/or processing the fibrous material web.

Description

The invention relates to a method for applying coating medium in at least two layers on the surface of a running paper, cardboard or other fibrous web in a machine for producing and / or finishing the fibrous web with a curtain applicator, which the application medium in the form of a - or multilayer curtain substantially following the gravity gives off to the fibrous web on which deposits the application medium as a coating layer. The invention also relates to a device for applying at least two layers of application medium.

A generic curtain coating method is from the DE A1-100 12 344 known. A generic device with a curtain applicator for applying at least two layers is for example also from the DE-A1 102007 000782 known. In addition, from the DE-A1 197 03 466 the application of a white pigment layer instead of an expensive, bleached fiber-containing layer known.

The second-mentioned document DE-A1 102007 000782 discloses a commissioned work, in which several, ie at least two successively arranged application nozzles (slot dies, ie so-called slot this) are present. These individual application nozzles have identically constructed components and are combined to form a structural unit.

From the the EP-A1-1 255 615 is another embodiment of a curtain-commissioned work known in the art as "Slide Die", ie translated with Gleitschichtdüse. With this curtain commissioned work, several job media or multiple shifts of a job medium can also be issued. This so-called Gleitschichtdüse usually contains several application medium chambers. From such an application chamber branches off to the top of a supply gap, which in turn merges into a slot-shaped outlet nozzle. From this at least one slot nozzle, the respective application medium flows onto an outer sliding surface of the sliding layer nozzle. The application medium emerging from the outlet nozzles arranged parallel to one another in succession overlaps one another and passes from a tear-off edge or detachment line to the web to be coated.

These mentioned curtain coating methods work without contact. That is, the application medium is applied essentially only with the aid of gravity from above onto the substrate or the fibrous web to be coated. If you want a simple scrap paper from existing paper web, such. B. refining corrugated by providing them with a white pigment top coat, this very expensive application media are necessary. In addition, several such expensive layers are necessary to accomplish the necessary coverage of the carrier web - which is particularly important in cardboard or cardboard - to accomplish. Another disadvantage is that when these layers are applied by curtain coating, the anchoring of the first layer on the surface of the web is very inadequate and thus this expensive layer tends to flake off.

It is therefore an object of the invention to provide an improved method and apparatus for applying application medium in at least two layers on the surface of a running paper, cardboard or other fibrous web, which does not have the disadvantages of the prior art.

The object of the invention is achieved by a method having the features of claim 1. According to the invention, it is provided that first of all a precoat is applied to the surface of the fibrous web with a first coater, which is pressed into the surface of the fibrous web with a pressing element, the fibrous web running over a support surface, in particular a support roll, during the application of the precoat, and that subsequently applied with the curtain applicator application without application of an intermediate drying single or multi-layer coating layer forms a cover layer, which is referred to as cover coat.

The inventors have recognized that above all a good anchoring of the first layer on the fibrous web surface (carrier web) is important. By applying and especially pressing this first layer, this anchored in the carrier web. A subsequent top coat can thus combine very homogeneously with the pre-coat. So you save the previously very expensive cover line. The top coat must now have in its composition far less expensive ingredients than before. When applying the at least one subsequent pigmented top coat by means of wet in wet technique, d. H. without the provision of intermediate drying equipment, the overall application becomes particularly homogeneous and, moreover, fewer coater units or fewer different coater units are used.

The inventive method is characterized by high flexibility and meets all current market requirements.

It is useful in this context, if the precoat consists of starch or pigment-containing coating color and in an amount or a coat weight of 2 to 8 g / m ² and the top coat of pigment-containing coating color and is applied in an amount or a coat weight of 12 to 22 g / m ² .

The method according to the invention is particularly suitable for treating base paper produced inexpensively, for example corrugated cardboard or wastepaper-containing material, or finishing it with relatively little cost and effort.

The method according to the invention can preferably be used for the treatment or refinement of a corrugated paper web. Therefore, the invention also relates to a corrugated paper web treated by the method described above.

The object of the invention is also achieved by a device having the features of claim 4. According to the invention, a machine-wide curtain applicator is preceded by a first machine-wide applicator for applying a precoat. In addition, a likewise machine-wide support surface, in particular support roller is present, which is assigned at least the first commissioned work, wherein the fibrous web runs over the support surface during the application of the precoat and wherein the support surface is associated with a pressing element which presses the precoat in the surface of the fibrous web ,

The device according to the invention is characterized by its compactness, its flexibility and its small footprint.

With regard to the mentioned compactness and the space savings, it is very advantageous if the curtain applicator of the said support surface, in particular support roller is assigned. Since the application medium substantially falls by gravity from above down on the fibrous web, the curtain applicator is assigned to approximately the 12.00 o'clock position of the support roller.

In certain cases, it may also be useful - for example, if you want to make the curtain wider than the fibrous web - the curtain applicator away in the downstream direction of the support roller to arrange above a free, unsupported area of the fibrous web.

It is also advantageous that the curtain applicator is provided for applying the top coat, because you can simultaneously apply multiple layers, so even desired intermediate layers, with a single commissioned work. This curtain order is made without surplus order. That is, you only pay the amount that should remain on the track surface, which means a cost savings on media.

It is also possible without provision of intermediate drying units. As already mentioned in the explanation of the method according to the invention, the wet in wet application to the precursor causes a very homogeneous compound (the precoat is also a bonding layer) with this. As the top coat a total weight of about 12 to 22 g / m ^{2 is} provided.

To apply the precoat or the binding layer, the first commissioned work is provided. This commissioned work is assigned to the support surface in about a 3.00 o'clock position. As line weight come here, as already described in the process, about 2 to 8 g / m ² into consideration. In a preferred embodiment, this first application unit should apply the application medium in an indirect manner to the fibrous web and, for this purpose, should have an application roller and a metering element assigned to this application roller. The application roller applies the necessary pressure to the application medium and thus forms the said pressing element for pressing the precoat into the carrier web.

In an alternative embodiment, however, it can also be provided that the first application unit applies directly. For example, there is a per se known free-jet nozzle applicator, a Walzenauftragswerk (with scoop roller) or commissioned work with short exposure time, each of which a metering device in the form of a doctor blade or a rotary metering rod is downstream, in question. The doctor elements of the mentioned metering device, which are acted upon by a pressing force, form here the said pressing element.

The above-mentioned commissioned works are each assigned to the support surface or the support roller approximately at the 6 o'clock position, while the respective squeegee element acting as a pressing element is arranged in the 3 o'clock position. In this case, the wrap angle of the fibrous web around the support surface or the support roller is more than 180 °. The wrap angle is measured from the feed point of the web, which is approximately at 11 o'clock position, to at least the runoff point of the fibrous web located at 6 o'clock to 7 o'clock from the support surface.

A further expedient embodiment of the device can consist in that the support surface, in particular the support roller, is assigned a further application device or a moistening device for applying water or a water-starch mixture on the opposite side of the web. This makes it possible to avoid a so-called curl tendency of the fibrous web. This further application device can be arranged in about a 6:00 o'clock position. In this version is preferred the indirectly working first commissioned work in the 3.00 o'clock position in the employment.

It should be added that the curtain applicator unit can be designed both as a slot nozzle known per se (slot die, tandem die, twin die) and as a slide layer nozzle known per se (slide die).

Incidentally, the device according to the invention can easily be installed overnight in existing production and / or finishing machines or simply retrofit the existing machines because the device requires relatively little space. Unused units or commissioned works and metering devices, eg. B. if desired, to be converted to a "single line" can be swivel easily.

The invention will be explained in more detail with reference to an embodiment.

It shows in a schematic representation:

1 : A first embodiment of a schematically illustrated device according to the invention in side view

2 : A second embodiment of a schematically illustrated device according to the invention in side view

In the figures, the same components are provided with the same reference numerals.

In the 1 is a device 1 for applying at least two layers of application medium to the surface of a running paper, board or other fibrous web 2 in a machine 3 for producing and / or refining the fibrous web 3 shown. The in the direction L through the machine 3 moving fibrous web 2 First, the last drying cylinder happens 4 a double row pre-dryer section shown here 5 before placing the applicator 1 This device tapers 1 has one above the current fibrous web 2 arranged and over the machine width, ie in the transverse direction Q extending curtain applicator 6 on. The curtain commissioned work 6 which either as in 1 can be seen as a slot (slot) is formed, but also as Gleitschichtdüse (slide die) can be formed from one or more nozzle slots simultaneously at least one application medium in the form of a single or multi-layer curtain 7 essentially following gravity on the fibrous web 2 from. There lies the curtain 7 as a coating layer and thereby forms a single or multi-layer cover layer or the top coat 8th ,

In the 1 is recognizable that the curtain commissioned work 6 in the upstream direction of the fibrous web a first machine-wide commissioned work 9 for applying a primer 10 is upstream. Recognizable in 1 is also that a support surface 11 , Especially backup roll is present. This support surface 11 or support roller (it could also form a revolving endless belt, the support surface) is also machine-width. The preferably designed as a roller support surface 11 has a diameter of about 1500 mm, is with a drive 12 provided and runs counterclockwise, as the curved direction arrow R indicates. This is your first commissioned work 9 assigned to the fibrous web 2 during the application of the precoat 10 over the support surface 11 running. The support surface 11 is also a pressing element 13 assigned to the primer 10 level and into the surface of the fibrous web 2 pressed. In the example of 1 is specified that also the curtain commissioned work 6 , as a second commission, the supporting surface 11 or the backup roller is assigned and is there in the 12:00 o'clock position.

The one with the curtain commissioned work 6 applied cover layer or the top coat 8th is without provision of intermediate drying units, ie wet on wet on the precoat 10 applied. As a top coat 8th a coating medium in the form of so-called "White Top Liner" or "White Test Top Liner" is provided. This medium is used in the so-called 1: 1 application process, ie in the amount in which the medium on the web 2 should also remain, applied. Overall, the weight for this purpose is about 12 to 22 g / m ² , whereas the one with the first commissioned work 9 applied primer 10 , which is a bonding layer between the surface of the fibrous web 2 and the top coat 8th represents, has a coating weight between 2 and 8 g / m ² .

The first commissioned work 9 , which applies the application medium in an indirect manner and in excess to the fibrous web, has an applicator roll for this purpose 9a and one of these applicator roll 9a associated dosing or application unit 9b on. The said pressing element 13 is here by the applicator roll 9a , which has a diameter of about 800 mm formed. Like from the 1 Removable, is this first commissioned work 9 at about a 3 o'clock position on the support surface 11 or support roller.

As well as in 1 it can be seen, is the outer circumference of the support surface 11 , In particular the backup roller in about 6.00 o'clock position a humidifier 14 assigned for the application of water or a water-starch mixture. This avoids a curl tendency of the fibrous web, which is particularly useful in the case of less solid, or based on waste paper based webs or a corrugated board.

The now with primer 10 and top coat 8th provided fibrous web continues to run through the machine 3 by running from about 9.00 o'clock position from the support surface and down through a non-contact deflector 15 , a so-called Airturn is performed. Then the train 2 headed upstairs again while using contactless dryers 16 , which consist of hot air dryers and infrared dryers as well as drying cylinders 17 a night dry section 18 and subjected to further treatments (eg backside treatment, smoothing, rolling, etc.). It should be mentioned that the fibrous web can also be smoothed before it is coated.

The device can be easily installed in existing machines. Also, machines can be retrofitted or retrofitted.

That is why in 1 also an alternative web guide indicated. This web guide is possible when converting to another driving style z. B. if only a single line and no top coat should be applied. In this case, the one with the first commissioned work 9 coated fibrous web 2 above the support surface 11 directed upwards and here via a contactless drying system 19 , consisting of contactless deflection 19a and overlying drying hood 19b directed. This contactless drying system 19 is distributed by the company of the applicant as a so-called HCB-Turn. The alternative web guide described here is in 1 indicated by dashed lines.

In the 2 is a second embodiment of a device 2 shown. This should only be described to the extent that changes compared to in 1 shown device 1 result.

Unlike in 1 shown device 1 the fibrous web is running 2 initially coming from below via several guide rollers 20 and wraps around the support surface formed as a roller 11 Starting at about the 7:00 o'clock position until the 12:00 o'clock position or further counterclockwise until the 11:00 o'clock position. From the latter position, the one with a primer runs 10 and top coat 8th provided railway 2 continue and happens while contactless dryer 16 and a deflecting device 15 ,

In this device 2 also can the curtain commissioned work 6 in the direction L of the fibrous web 2 seen, in the downstream direction of the support surface 11 away, above a free, unsupported area 21 the fibrous web 2 be postponed. This is indicated by the double arrow V for an adjustment.

Unlike the execution according to 1 Here is the first commissioned work 9 as directly applying free-jet nozzle applicator 9c , or designed as a roller applicator or as a commissioned work with a short exposure time. This commissioned work, because this applies in excess, a metering device 9d arranged downstream in the form of a doctor blade or a rotary metering rod. The commissioned work 9 is here in 6:00 o'clock position. The metering device 9d in this case forms the said pressing element 13 for pressing in the precoat 10 in the railway surface and is located approximately in the 3.00 o'clock position.

To explain will be added that the support roller shown in the two figures 11 runs counterclockwise, as indicated by directional arrow R. To the arrangement of commissioned units or units on this support roller 11 clearly defined, the selected positions were given in the form of times.

LIST OF REFERENCE NUMBERS

1, 2

Device for applying

2

Fibrous web

3

machine

4

drying cylinders

5

pre-dryer

6

Curtain applicator

7

curtain

8th

topcoat

9

first commissioned work

9a

applicator roll

9b

Dosing element or application unit

9c

Free jet nozzle applicator

9d

metering

10

primer

11

support surface

12

drive

13

press member

14

humidifying

15

deflecting

16

contactless dryer

17

drying cylinders

18

Afterdryers

19

contactless drying system

19a

deflecting

19b

Trockenhaube

20

guide roll

21

unsupported area

L

direction

R

arrow

V

adjustment

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10012344 A1 [0002]
• DE 102007000782 A1 [0002, 0003]
• DE 19703466 A1 [0002]
• EP 1255615 A1 [0004]

Claims (15)

Method for applying application medium in at least two layers to the surface of a running paper, board or other fibrous web ( 2 ) in a machine ( 3 ) for producing and / or refining the fibrous web ( 2 ) with a curtain commissioned work ( 6 ), which the application medium in the form of a single or multilayer curtain ( 7 ) substantially following gravity to the fibrous web ( 2 ), on which the order medium deposits as a job layer, characterized in that first with a first commissioned work ( 9 ) a primer ( 10 ) on the surface of the fibrous web ( 2 ) is applied, which with a pressing element ( 13 ) in the surface of the fibrous web ( 2 ), wherein the fibrous web ( 2 ) during the application of the precursor ( 10 ) via a support surface ( 11 ), in particular supporting roller runs and whereby the afterwards with the curtain commissioned work ( 6 ) applied without application of an intermediate drying application layer a top coat ( 8th ). Method according to claim 1, characterized in that the primer ( 10 ) forms a binding layer and is applied in an amount or a coating weight of 2 to 8 g / m ² and the top coat ( 8th ) consists of pigment-containing coating color and in an amount or a coating weight of 12 to 22 g / m ^{2 is} applied. Corrugated paper web, characterized in that it is coated with a method according to the preceding claims. Contraption ( 1 . 2 ) for applying at least two layers of application medium to the surface of a running paper, board or other fibrous web ( 2 ) in a machine ( 3 ) for producing and / or refining the fibrous web ( 2 ), comprising one above the continuous fibrous web ( 2 ) and extending across the machine width curtain applicator ( 6 ), from which at least one application medium in the form of a monolayer or multilayer curtain ( 7 ) substantially following gravity on the fibrous web ( 2 ) and deposits there as a coating layer, characterized in that the curtain commissioned work ( 6 ) a first machine-wide commissioned work ( 9 ) for applying a primer ( 10 ) and a machine-wide support surface ( 11 ), in particular support roller is present, at least the first commissioned work ( 9 ), wherein the fibrous web ( 2 ) over the support surface ( 11 ) during the application of the precursor ( 10 ) and wherein the support surface ( 11 ) also a pressing element ( 13 ), which is the primer ( 10 ) in the surface of the fibrous web ( 2 ) presses. Apparatus according to claim 4, characterized in that the curtain applicator ( 6 ) of the support surface ( 11 ), in particular the support roller is assigned and is there in about the 12.00 o'clock position. Apparatus according to claim 4, characterized in that the curtain applicator ( 6 ) in the running direction (L) of the fibrous web ( 2 ) seen in the downstream direction of the support roller ( 11 ) and above a free, unsupported area ( 21 ) of the fibrous web ( 2 ) is located. Device according to one of claims 4 to 6, characterized in that the curtain applicator ( 6 ) for applying at least one top coat ( 8th ), without the provision of intermediate drying units, ie wet in wet on the precoat ( 10 ) and wherein the at least one top coat ( 8th ) has a total weight of about 12 to 22 g / m ² . Apparatus according to claim 4, characterized in that the first commissioned work ( 9 ) for applying the primer ( 10 ), this primer ( 10 ) has a coating weight of about 2 to 8 g / m ² . Apparatus according to claim 8, characterized in that the first commissioned work ( 9 ) as a free-jet nozzle applicator ( 9c ), Walzenauftragswerk or commissioned work with a short exposure time, each a metering device ( 9d ) is arranged downstream in the form of a doctor blade or a rotatable metering rod, this metering device ( 9d ) said pressing element ( 13 ). Apparatus according to claim 9, characterized in that the first commissioned work ( 9 ) in about a 6.00 o'clock position of the support surface ( 11 ) or backup roller is assigned. Apparatus according to claim 4, characterized in that the first commissioned work ( 9 ) the application medium in an indirect manner on the fibrous web ( 2 ) and an application roller ( 9a ) and one of these applicator roll ( 9a ) associated dosing element ( 9b ), wherein the applicator roll ( 9a ) said pressing element ( 13 ). Apparatus according to claim 11, characterized in that the first commissioned work ( 9 ) in about a 3.00 o'clock position of the support surface ( 11 ) or backup roller is assigned. Device according to at least one of the preceding claims, characterized in that the curtain applicator ( 6 ) as a slot nozzle (slot die) or as Gleitschichtdüse (slide the) is formed. Device according to claim 4, characterized in that the support surface ( 11 ), in particular the support roller in about a 6.00 o'clock position a humidifying device ( 14 ) is assigned to the application of water or a water-starch mixture. Device according to at least one of the preceding claims, characterized in that it can be installed overnight in existing manufacturing and / or finishing machines or said machines are convertible.

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