DE102012205074A1 - Apparatus e.g. for producing single-or double-sided- moving paper, comprises a applicator for coating medium, which is switched from coating operation to humidifying operation, and a downstream doctor blade device for dosing coating medium - Google Patents

Abstract

Apparatus for producing a single-or double-sided- and single-or multi-layered moving paper, cardboard, or other fibrous web (2), comprises: at least one applicator (5) for the coating medium; and a downstream doctor blade device for dosing and/or leveling the previously applied coating medium, where the applicator is switched from a coating operation to a humidifying operation, during which the uncoated or pre-coated web side of the fibrous web is associated with a spraying device acting across the width of the fibrous web, for applying a humectant to a specific web side. Apparatus for producing a single-or double-sided- and single-or multi-layered moving paper, cardboard, or other fibrous web (2), preferably a paper web with low basis weight in a running direction by a manufacturing- and/or finishing- or a coating machine (1), comprises: at least one applicator (5) for the coating medium for applying a pigment-containing-, liquid to pasty coating medium on both sides of the web, where the applicator is present in the form an application unit arranged in the running direction of the fibrous web; and a downstream doctor blade device for dosing and/or leveling the previously applied coating medium, and which in the web running direction is connected at a first applicator for a web side of a first drying device (7) and then a second applicator for a further web side and a second drying device (10) and the applicators perform the coating operation on both the sides of the web alternately with each other, where the applicator is switched from a coating operation to a humidifying operation, during which the uncoated or pre-coated web side of the fibrous web is associated with a spraying device acting across the width of the fibrous web, for applying a humectant to a specific web side and the application unit remains unused and the doctor blade device is provided for stripping and/or to equalize the deposited humectant.

Description

The invention relates to a device for producing a single- or double-sided, one or multiple coated by a manufacturing and / or finishing or coater paper-carton or other fibrous web, in particular a paper web of small surface-related mass, in which for applying of pigment-containing, liquid to pasty coating medium on both sides of the web at least one commissioned work for the coating medium is assigned and at least one commissioned work in the form of a coating unit and this application unit seen in the direction of the fibrous web, downstream doctor device for metering and / or equalization of the previously applied coating medium and in the web running direction to a first commissioned work for the one web page a drying device and then a second commissioned work for the other web page and a drying device connects and the commissioned works on both sides of the web alternately exercise their coating operation.

From the DE A1-4414921 such a generic device can be removed. The coating of only one side of the web entails undesirable stretching and swelling of the fibrous web, whereby the fibrous web has a tendency to curl or roll. This curl is referred to as curl, the curl is dependent on the quality and moisture of the fibrous web. For lightweight papers, ie papers with a low grammage, there is a stronger tendency to curl, ie curl, than for papers with higher masses. Curl has a negative effect on the running behavior of the fibrous web, which is why it is anxious to avoid the curl.

In the WO A1-2011 / 115013 It is disclosed that the curl is countered by controlling the heating temperature of the drying device following the last coat application. The heating temperature is set lower on the uncoated side than on the coated side. The setting is complicated and complicated.

In practice, by applying a humectant - usually water - applied to the uncoated side of the sheet. For this purpose, usually a roller applicator is used, which is designated by the company of the applicant as LAS (Liquid Application System). It consists of two rollers which form a nip and pass through the fibrous web to be moistened. The rollers are mounted on a support beam. The one roller, which touches the uncoated side of the web, is associated with a moistening unit which applies a film of water to the roller. In the nip, the water film is transferred to the fibrous web. This roller applicator is extremely compact and expensive. In addition, additional space is required within the manufacturing or finishing or coating machine for this LAS.

It is therefore an object of the invention to provide a device which has a simpler structure and with which the curling tendency (curl) of the single-coated web can be reliably reduced or prevented.

The object of the invention is achieved with a device according to claim 1. Advantageous embodiments will become apparent from the dependent claims.

According to the invention, it is provided that the applicator unit can be switched over from a coating operation to a moistening operation, wherein a spraying device acting on the width of the fibrous web for applying a moistening agent to this web side is assigned for the moistening operation of the still uncoated or already precoated web side. The application unit remains unused during the moistening operation and the existing doctor device is provided here to scrape off and / or to even out the applied moistening agent.

With the device according to the invention it is possible for the first time, without much effort, i. without the use of the known compact and expensive Walzenbefeuchtungswerks "LAS" (Liquid Application System), with which an application of the moistening agent (water) takes place in the form of a "thick" film by means of rotating applicator rollers to counteract an undesirable Curlneigung.

The curl tendency arises when a coating agent or liquid to pasty coating medium is applied on one side.

The inventors have recognized that the same commissioned work, which serves the actual coating operation, can also be used for a humidifying operation. Only the additional arrangement of the spray is necessary.

The proposed spray is relatively simple and able to deliver very atomized spray drops, instead of the previous water film application. The spraying device ensures a more even humidifier absorption over the entire width of the fibrous web. In addition, the spray is easier to handle and far less compact and expensive. This reduces investment costs and space requirements.

Preference is given to water as a liquid moistening agent, which is always sufficiently available in the field of a fibrous web, manufacturing or -Verelungsmaschine.

In principle, instead of the "simple" spraying device provided according to the invention, it would also have been possible to use the existing applicator, such as the blade coater, which is available for coating, glue or starch application (coating application). However, the amount of liquid moistening agent applied to the application unit, i. Water quantity for lightweight fibrous webs too high, as these light paper grades would quickly soak and tear off, which of course you want to avoid.

The spraying device of the device according to the invention is arranged according to a first variant in the area between the existing for the actual coating order, but unused application unit and the doctor device. This variant is applicable to fibrous webs, which have a high water absorption capacity where the moistening agent is to be made uniform immediately after application or spraying. The exposure time is short and a soaking of the web is avoided.

According to a second alternative variant, it is provided that the spraying device is arranged directly in front of the application unit which is present for the actual coating application but is unused. Here, the exposure time of the humectant is desired to be slightly longer. This variant is therefore suitable for thicker webs or webs with lower water absorption capacity.

The amount of moisturizer or water to be applied should be about 2 to 6 g / m ² . If this parameter is adhered to, in addition to curl avoidance, it is also possible to avoid soaking and tearing off of the web.

Said spraying device of the device according to the invention can be designed as a spray tube formed over the width of the fibrous web. The spray tube may be fixed and be provided with a plurality of nozzle openings - for example, with binary used - or adjustable in their direction of action flat nozzles. It would also be conceivable training with a consistently incorporated fine nozzle slot of 0.8 to 1.2mm width.

Also conceivable as a spraying device would be a nozzle or a plurality of nozzles, for example flat fan nozzles, which traverse the width of the fibrous web and which also ensure or ensure uniform moistening agent feed over the entire web width.

It is particularly advantageous that fibrous webs or papers with a low basis weight (FbM) can be treated with the device according to the invention. By "low basis weight" (FbM) are meant those papers which have a maximum FbM of 80 g / m ² , preferably 30 to 50 g / m ² .

With the aid of the device according to the invention, both wood-free paper (WFC) - so-called graphic paper and LWC magazine paper - can be produced in high quality. Above all, however, the device according to the invention is suitable for producing papers with a low surface-related mass.

The device according to the invention can easily be switched from moistening to coating operation and vice versa. The components used for this purpose can be provided in a modular manner and maintain. Often, their subsequent installation in existing machines is possible.

With the invention, investment costs are saved and the space required is less than before.

It should be noted that the invention can also be used with a coating to be carried out on only one side with a liquid to pasty coating medium. In this case, a squeegee device is then to be arranged on the opposite side of the web in addition to the spray.

The invention will be explained in more detail with reference to an embodiment. It shows a schematic representation of the

Figure: a manufacturing or finishing or coating machine for two-sided application with the device according to the invention

In the figure is a manufacturing or finishing or coating machine 1 recognizable by the one to be spread fibrous web 2 over guide rollers 3 and driven guide rollers 4 is running, of which in the figure but not each is marked with reference numerals.

The fibrous web to be spread 2 in the example is a paper web with a low surface mass of less than 50 g / m ² .

For coating one side of the sheet 2a with pigment-containing coating color M serves a first commissioned work 5 , This commissioned work 5 is a so-called direct coating in the form of a blade coater, consisting of a coating unit 5.1 or nozzle application unit with a continuous nozzle and downstream in the web running direction L doctor device 5.2 , The doctor element used here is a doctor blade (blade) 5.3 , But it could also find a cylindrical squeegee use.

The commissioned work 5 ie order aggregate 5.1 and squeegee device 5.2 . 5.3 are, as I said, the web page 2a assigned, but also a support roller 6 about the railway 2 running.

In the path of the coated fibrous web 2 are still drying equipment below 7 , like IR dryer 7.1 , Hot air dryer 7.2 and contact dryer or a drying cylinder arrangement 7.3 ,

For subsequent coating of the other side of the web 2 B are in principle the same assemblies that are used to coat the first web page 2a necessary, available.

You can see a second commissioned work 8th , This commissioned work 8th is also like the commissioned work 5 formed and consists of a job aggregate 8.1 and a downstream in the web direction L doctor device 8.2 with doctor blade 8.3 , The commissioned work 8th ie order aggregate 8.1 Squeegee device 8.2 and blade 8.3 are the train side 2 B assigned, via a back-up roller 9 running. Below are also drying facilities 10 , like IR dryer 10.1 , Hot air dryer 10.2 , Contact dryer or a drying cylinder arrangement 10.3 and a non-contact deflection device 10.4 available.

So that you can reduce a curl (curl) of the web or even better prevent, is the commissioned work 5 and 8th switchable from a coating company I as exemplified by the commissioned work 5 is shown in a humidifying operation II , The humidification operation II is an example of the commissioned work 8th shown.

This is the still uncoated or in a previous step, not shown, already pre-coated web page 2 B a spraying device acting across the width of the fibrous web 11 for applying a humectant 11a on the railway side 2 B assigned. The application aggregate 8.1 is, as it remains unused here simply swung. This is indicated by the small curved double arrow underneath.

The likewise existing doctor device 8.2 or the blade or the blade 8.3 now serves, the applied wetting agent 11a strip and equalize.

As can be seen from the figure, in a first variant A is the spray device 11 in the area between the existing but unused order aggregate 8.1 and the squeegee device 8.2 arranged.

With a dashed line a second variant B is indicated. Here is the spray 11 who are here with 11 ' is called, immediately before the existing but unused order aggregate 8.1 arranged. In this variant, the humectant 11a slightly longer than the first variant A on the web page 2 B act before it with the blade 8.3 stripped and evened out.

The sprayer 11 as well as 11 ' are the same. A simple construction is that a spray tube 11.1 is present, which is the humectant 11a Finely atomized over the entire width of the fibrous web side 2 B applies. For example, flat jet nozzles or a multiplicity of other individual nozzles can be used.

Per m ^{2 of} web surface, only about 2 to 6 g of water in the form of spray drops are necessary for moistening to avoid the curl. The pressure of the humectant or of the water was chosen in the example about 3 bar.

LIST OF REFERENCE NUMBERS

1

 Manufacturing or finishing or coating machine

2

 Fibrous web

2a

 web side

2 B

 web side

3

 guide roll

4

 driven guide roller

5, 8

 commissioned

5.1, 8.1

 Application unit or nozzle application unit

5.2, 8.2

 doctor device

5.3, 8.3

 Scraper blade or blade

6, 9

 supporting roll

7, 10

 drying device

7.1, 10.1

 IR dryer

7.2, 10.2

 Hot air dryer

7.3, 10.3

 contact dryer

10.4

 non-contact deflection device

11, 11 '

 spraying

11a

 humectants

11.1

 lance

A

 first variant

B

 second variant

L

 direction

M

 coating color

I

 coating operation

II

 humidifying

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 4414921 A1 [0002]
• WO 2011/115013 A1 [0003]

Claims (7)

Device for producing a one- or two-sided, single or multiple coated, in the running direction (L) by a manufacturing and / or finishing or coating machine ( 1 ) running paper board or other fibrous web ( 2 ), in particular a paper web of small surface-related mass, in which for the application of pigment-containing, liquid to pasty coating medium both web sides ( 2a . 2 B ) at least one commissioned work ( 5 . 8th ) is assigned to the coating medium and the at least one commissioned work ( 5 . 8th ) in the form of an order aggregate ( 5.1 . 8.1 ) and a coating unit in the running direction (L) of the fibrous web ( 2 ), subordinate squeegee device ( 5.1 . 8.2 ) for metering and / or leveling of the previously applied coating medium and in the web running direction (L) to a first commissioned work ( 5 ) for the one web page ( 2a ) a drying device ( 7 ) and then a second commissioned work ( 8th ) for the other web page ( 2 B ) and a drying device ( 10 ) and the commissioned works ( 5 . 8th ) both sides of the web ( 2a . 2 B ) alternately their coating operation ( I ), characterized in that the commissioned work ( 8th ) is switchable by a coating company ( I ) into a humidifying operation ( II ), wherein for the humidifying operation ( II ) of the still uncoated or the already pre-coated web page ( 2 B ) of the fibrous web ( 2 ) acting over the width of the fibrous web spraying device ( 11 . 11 ' ) for applying a moistening agent ( 11a ) on the relevant web page ( 2 B ) that the application unit ( 8.1 ) remains unused and that the existing doctor device ( 8.2 ) is provided to the applied wetting agent ( 11a ) and / or uniform. Device according to claim 1, characterized in that the spraying device ( 11 ) in the area between the existing but unused order aggregate ( 8.1 ) and the doctor device ( 8.2 ) is arranged. Device according to claim 1, characterized in that the spraying device ( 11 ' ) immediately before the existing but unused order aggregate ( 8.1 ) is arranged. Device according to one of the preceding claims, characterized in that as wetting agent ( 11a ) Water is provided. Apparatus according to claim 4, characterized in that the amount of moistening agent to be applied ( 11a ) is about 2 to 6 g / m ² . Device according to one of the preceding claims, characterized in that the spraying device ( 11 . 11 ' ) as over the width of the fibrous web formed spray tube ( 11.1 ) with a plurality of juxtaposed and / or successively arranged nozzle openings ( 11.2 ) or a continuous nozzle slot ( 11.3 ) is trained. Device according to one of claims 1 to 6, characterized in that the spray device ( 11 ) as across the width of the fibrous web traversing nozzle ( 11.4 ) is trained.

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