DE10352865A1 - Method and device for coating sheet-like substrates such as paper - Google Patents

Abstract

The present invention relates to a process for coating a sheet-like substrate, in particular paper, adhesive paper, cardboard, textiles or films, with a coating agent, in particular with a silicone oil emulsion, in which the coating agent is applied to the substrate by means of at least one application device. In order to achieve a particularly uniform application of the coating composition to the substrate, it is proposed according to the invention to abandon the coating agent by means of a metering device to at least one storage device made of sponge-like, moisture-storing material, which optionally is transferred from there via an intermediate device to the at least one discharge device. Furthermore, the present invention relates to a device suitable for carrying out the method according to the invention for coating a sheet-like substrate and to a coated substrate obtainable by the method according to the invention, in particular paper.

Description

The The present invention relates to a method for coating a sheet-like substrate, in particular of paper, adhesive paper, cardboard, textiles or foils, with a coating agent, in particular with a silicone oil emulsion, wherein the coating agent by means of at least one applicator is applied to the substrate, a corresponding device and a coated substrate obtainable by the process.

such Methods and devices are described i.a. in the finishing of paper or cardboard used, which due to the different claims that from the processing industry and the end user Such materials are required is required. When painting, one important process of paper finishing, is applied to the base paper before its equipment, d. H. its division into the required format, a coating color composed of pigments and binders, whereby the Paper receives a closed and well printable surface. A subsequent smoothing the paper surface can be by calendering the paper web in a calender, in which the Paper under pressure passing through several heated rollers, reach, making the paper smoothness and gloss and improves the printability of the paper becomes. As a binder, these methods are usually Latex, synthetic resin or starch ether used while inorganic pigments as pigment, such as calcium carbonate, talc, Kaolin or the like can be used.

One Another field of application of the aforementioned methods and devices is the lamination example. Of paper or plastic film, in which on the sheet-like substrate a plastic film, for example, a coating solution containing an aqueous dispersion at least one acrylonitrile-vinyl-formic-acrylic acid ester copolymer, a styrene-acrylic acid copolymer, a styrene-methacrylic acid copolymer or the like is applied.

It has also been proposed, coating agent on printed Apply paper to the friction and electrostatic charge of the paper to reduce the pressure on printed paper.

From the US 4,637,341 a method and an apparatus for coating paper webs is known in which a silicone concentrate is first mixed with water in a mixing container to an aqueous silicone emulsion of desired concentration and pumped from there into a holding vessel, from which the emulsion with two successively arranged rolls on both sides the paper is applied by the printing machine during its processing. The coating agent is intended to lubricate the surface of the treated paper to facilitate singulation of the cut sheets and handling thereof. However, a disadvantage of this process is that it does not ensure a uniform application of the coating agent to the substrate.

In the DE 197 43 641 A1 is a system for coating carrier webs with a coating agent having at least one revolving, preferably on its outer surface acted upon by dipping with the coating agent and brought into contact with a web page to be coated applicator roll disclosed in the order of a roll subordinate smoothing roll for area-wide distribution and injection of the applied coating agent is provided. In order to achieve the most uniform possible distribution of the coating agent on the carrier web, the applicator roll should have a rough surface, wherein the minimum roughness is between 0.1 and 0.5 microns. However, such rolls are very sensitive to mechanical forces acting on the surface and are very expensive to produce. In addition, these ensure no uniform application of the coating agent due to the roughness of the Auftragswalzenmantelflächen at high speed. Since the system for double-sided coating of paper webs must be equipped with at least two anilox rollers as applicator rollers, also significant investment costs are needed. Another disadvantage of this system is in their due to the successively arranged rollers, design-related size and that it must necessarily have a drive for the applicator rollers, since the staggered rollers arranged only by a promotion of the paper can not be set in rotation.

task The present invention is therefore a method for coating a sheet-like substrate, in particular of paper, adhesive paper, cardboard, textiles or foils, with a coating agent, which is easy and cost-effective perform is as well as having a compact, structurally simple, in particular economical producible, easily convertible and robust device executable is.

This object is achieved by a method of the type mentioned by solved that the coating agent is first applied by means of a metering device to a storage device of spongy, moisture-storing material and from there optionally via an intermediate device to the applicator, for example. A roller is transferred before the coating agent is applied to the substrate via the applicator ,

Surprisingly can be with this method coatings desired layer thickness with excellent uniformity or apply to the substrate on both sides. In addition, that requires inventive method ren only a comparatively compact, structurally simple and economical manufacturable device, which is also robust and flexible to the special requirements, such as the format of the coated Substrate, can be adjusted. In particular, to carry out the inventive method no expensive and wear-prone anilox rollers required; rather, this is even with the use of applicator rolls with a smooth surface thanks to the at least one storage facility compared to the order with anilox rolls, more even Order of the coating agent reaches the substrate. This is due to that the coating agent in the storage medium due to the liquid-storing Property evenly distributed and thus, based on the longitudinal axis of Application roller, evenly on transfer the order device can be. The storage medium thus fulfills in principle the same Function as the lateral surface roughness the known anilox rolls leads but in comparison to these, especially at slower web speed / bow speed, to better results.

According to the invention that at least one storage medium from each sponge-like, moisture-storing Consist of material which has a sufficient liquid storage capacity, for an even distribution the liquid to ensure in the material. Suitable materials include, for example, felt, nonwoven, sponge rubber, Foam or pulp, wherein the material is preferably a average pore size from 1 μm to 1 mm, more preferably 50 microns up to 750 μm and most preferably from 100 to 200 microns. Especially wool felt, For example, those with a wool content of 90%, with a density after DIN 612000 of 0.36 (F2) has proved to be a particularly suitable material for the Storage medium proven.

The inventive method is suitable for both single-sided and double-sided coating of sheet-like substrates. Preferably is for a two-sided coating the coating agent simultaneously on the two sides of the substrate to be coated by means of two, from seen from the substrate, oppositely arranged applicators applied, wherein the coating means the two applicators possibly over in each case an intermediate device in each case by a storage device from sponge-like, moisture-storing material to which the coating agent over a metering continuously or discontinuously abandoned is fed becomes.

In Further development of the inventive concept is proposed, the coating agent to the at least one storage device via one or more Comprehensive nozzles Apply metering device. It has also proven to be beneficial proven to use atomizer nozzles, which at least one coarse atomization effect of the binder. Preferably, the individual nozzle heads are in one arranged such a distance from each other, that on the one hand a minimum number of nozzles needed but on the other hand one possible even order, relative to the longitudinal axis the storage device, the coating agent on the storage device is ensured. Therefore, the individual nozzles are particularly preferred arranged that the spray areas two adjacent nozzles just overlap. A particular advantage of the application of the coating agent on the storage means by means of nozzles is that the width the metering device of the substrate used by adding or switching off individual nozzles constructively simple and inexpensive can be adjusted.

When At least one applicator can in principle all the expert means known for applying coating agents to sheet substrates be used. Preferably be rotatably mounted as applicator Roll used, which particularly preferably a lateral surface Rubber, metal or steel. In particular suitable are on application rollers with a lateral surface made of rubber, as this comparatively inexpensive and sufficiently robust are, but still a uniform coating of the substrate.

In accordance with a particular embodiment of the present invention, applicator rolls having a smooth envelope surface are used as application means, since they are more robust to mechanical influences than anilox rolls and nevertheless ensure uniform coating of the substrate due to the supply of coating agent via a storage device. Of course, equally good results can be achieved with anilox rollers, in particular with those of a roughness of the jacket surface between 0.1 and 1 .mu.m, which are less preferred for the reasons mentioned.

in principle the at least one application device can communicate directly with the memory device liquid transferring be connected. However, it has proven to be beneficial between the application device and the storage device have an intermediate device, particularly preferably to use an intermediate roll, both with the applicator as well as with the storage device liquid-transmitting is connected, i. in relation to the two latter bodies is arranged such that the coating agent from the storage device transferred to the intermediate roll and from the intermediate roll to the applicator roll becomes. The intermediate roller will further increase the uniformity of the coating agent applied to the substrate.

Preferably is as an intermediate roll such with a lateral surface Rubber, metal or steel, in particular with a lateral surface of one Chromium alloy, used. Analogous to the application rollers can for this Purpose but also, albeit less preferred, an anilox roller, in particular one with a roughness of the lateral surface between 0.1 and 1 microns, used become.

in principle the method according to the invention is suitable for the Coating of all to be coated sheet-like substrates, in particular at the coating of paper, adhesive paper or cardboard especially good results are achieved.

Further can the inventive method for all known coating compositions are used, in particular for Painting and / or laminating paper.

In Further development of the concept of the invention is proposed, the method according to the invention for coating by means of offset or digital printing to use printed paper or cardboard. Preferably, the printed substrate for this purpose with a silicone oil emulsion, in particular with a polydimethylsiloxane containing one or more Emulsion, coated. The coating is preferably carried out in a temperature range of 5 to 35 ° C, more preferably at room temperature. In this way, paper is obtained, which is characterized by an excellent surface scratch resistance and aging resistance and also antistatic, moisturizing and is haptic. Due to the scratch resistance u.a. a blur the pressure after printing, for example, as a result of further processing, such as Grooving, folding, stapling or the like. Avoided. For this purpose will be the silicone oil emulsion if necessary by dilution with water to a suitable viscosity, more preferably a viscosity between 1 and 1,000 mPa · s, set. Particularly good results are with waxy Silicone oil emulsions scored for In principle all known to those skilled waxes, in particular natural Waxes, such as bee or paraffin waxes, or synthetic waxes, such as polyalkenyl or polyethylene glycol waxes are suitable. Of course you can Silicone oil emulsions besides or alternatively to wax also other additives, in particular Paints and / or odors, for example. Enclosed in microcapsules Odorants, be added.

One particular advantage of the present method is that it re the dimensions of the substrate to be used extremely flexible and quickly from one to another substrate format and / or another Grammage strength converted can be. To do this only the applicator rollers and possibly intermediate rollers against such the desired one Length exchanged and the number of dosing nozzles by switching off or adding individual nozzles are adjusted, whereas the storage device remain unchanged can. In particular, the method is suitable both for substrate webs as well as for already tailored substrates.

One Another object of the present invention is a device for coating sheet-like substrates, which in particular to carry out the method according to the invention suitable is.

According to the invention the device at least one application device for order of the coating agent on the substrate, at least one metering device and at least one storage device of sponge-like, moisture-storing Material, wherein the memory device with the at least one Ordering facility possibly via an intermediate device fluid-transmitting is connected and the arranged at least one metering device is that of this coating agent on the storage device can be abandoned.

The at least one storage medium may consist of any sponge-like, moisture-storing material which has a sufficient liquid storage capacity to ensure a uniform distribution of liquid keit in the material. Suitable materials include, for example, felt, nonwoven, sponge rubber, foam or fiber, wherein the material preferably has a mean pore size of 1 .mu.m to 1 mm, more preferably from 50 .mu.m to 750 .mu.m, and most preferably from 100 to 200 .mu.m. In particular wool felt, for example those with a wool content of 90%, with a density according to DIN 612000 of 0.36 (F2) has proven to be a particularly suitable material for the storage medium.

According to one particular embodiment of the present invention, the device comprises two order, Additional, storage and metering devices, the two applicators, from the substrate, opposite to each other on both sides of the substrate are arranged, both application devices each with an additional device, the additional devices each with a Memory device and the memory devices each with a Dosing device liquid-transmitting are connected. About liquid-supporting In the present case, an arrangement of two devices is referred to one another such that during operation of the device, liquid from a device transferred to the other becomes.

Preferably the at least one metering device comprises one or more nozzles, particularly preferably one or more atomizer nozzles.

In Development of the inventive concept is proposed as at least an applicator means a roller, more preferably a roller with a lateral surface made of rubber, metal or steel, in particular with a lateral surface Rubber, and most preferably with a smooth outer surface comprises.

Provided an intermediate device is provided, this is preferably a roller, particularly preferably a roller with a lateral surface Rubber, Me tall or steel and most preferably with a lateral surface from a chrome alloy.

According to one preferred embodiment of present invention, the device has a control unit on which the rotational speed of the at least one application device and / or the feed cycle times of the at least one metering device and / or controls the feed stream of coating agent via the metering device. Alternatively, it is of course also possible, a Provide control device, which depends on the given Thickness of the coating to be applied to the substrate independently Rotational speed of the rollers and the coating agent supply cycle the nozzles regulates. in principle holds that the larger the desired Thickness of the coating to be applied, the longer the given rotational speed the applicator rolls the Zufuhrtaktzeiten the nozzles or the greater the the nozzles supplied Stream of coating agent.

One Advantage of the device according to the invention lies in the fact that these compact, structurally simple and inexpensive to produce is. In addition, this is universal, u.a. both for substrate webs as well as cut to size Substrates, and can be used by replacing the order and if necessary intermediate device and shutdown or addition of individual nozzles easy converted to other substrate formats become. Furthermore allows this one uniform coating of sheet-like substrates at any layer thickness. Another advantage of the device according to the invention lies in the fact that these are both integrated into the printing press as can also be used in isolation thereof. In the latter case is in contrast to the coating devices known from the prior art, which Device independent to operate from the speed of the printing press. Especially Due to the compactness of the device, this can be almost any be used anywhere. Moreover, the method according to the invention unlike devices with anilox rollers presupposing Procedure, without conversion the device used infinitely adjustable. Finally allowed the device according to the invention, since the amount of coating agent applied to the substrate not just about the rotational speed of the rollers, but also over the Metering device can be controlled, the top and bottom of the substrate with a different layer thickness of coating agent to provide.

Of Furthermore, the present invention relates to a coated sheet-like substrate, which with the method according to the invention available is, in particular coated paper or cardboard, which with a waxy silicone oil emulsion is coated. This paper is characterized by an excellent surface scratch resistance as well as aging resistance and is also color neutral, antistatic, moisturizing, haptic and yellowed Not. In particular, the increased Scratch resistance of the coated substrates is significant as smearing or blurring of the imprint the further processing, for example. By grooving, folding, sorting, stapling and the like, the paper reliable is prevented. Nevertheless, the paper remains writable or printable. by virtue of the antistatic properties of the paper thus obtained tends this less for sticking together with other paper sheets, which also means further processing, especially the sorting, relieved.

Other objects, features, advantages and applications of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. In this case, all described and / or illustrated Features alone or in any combination, the subject of the present invention, also regardless of their summary in individual claims or their dependency.

In the single figure is one for carrying out the method according to the invention suitable device according to a embodiment shown.

The device shown in the figure 1 is used for double-sided coating in particular of printed paper, adhesive paper or cardboard with a silicone oil emulsion as a coating agent, in which the substrate to be coated 2 either in the form of a paper or board web or already in cut form can be used.

The device 1 includes two rubber rollers 3 as an applicator, between the lateral surfaces of the substrate, eg. By means of digital printing printed paper, is performed. To ensure adequate pressure of the rollers on the substrate 2 to ensure are the two rolls 3 preferably biased with a spring of suitable restoring force or in a to the thickness of the substrate to be coated 2 adjusted distance from each other. The promotion of the substrate 2 through the two rollers 3 is done either by one or both rollers 3 be driven by a motor at a corresponding speed, or by passing the substrate through the rollers 3 pushed or pulled by an external drive. Of course it is also possible, both rolls 3 manually with a hand crank or the like. Preferably, the lateral surface of both rolls 3 smooth, since such compared to those with a rough surface, such as. Anilox rollers, more robust because less susceptible to wear, are. But it is of course also possible, although less preferred, rollers 3 to use with a rough surface.

At each of the substrate to be coated 2 opposite sides of the applicator rolls 3 each are a metal roller 4 arranged as an intermediate device such that the latter of the applicator rolls 3 be driven and coating agent on the applicator rolls 3 can transfer. Also, the lateral surfaces of both intermediate rolls 4 are preferably smooth.

At about the 90 ° angle to the applicator rolls 3 offset are two memory devices 5 arranged in felt, which have approximately the shape of a cuboid and by means of a holder 6 with the two intermediate rollers 4 fluid-transmitting connected. It was a 90% wool felt with a density according to DIN 61200 of 0.36 (F2) used. Below the two storage devices 5 each is a drip pan 7 provided, which from the storage devices 5 dripping down coating takes up. Preferably, this is in the drip pan 7 collected coating agent to the storage vessel 11 returned, so that a circulation of the coating agent is achieved.

At each of the intermediate rollers 4 opposite sides of the storage devices 5 are a total of 15 linearly arranged side by side and in the holder 6 integrated nozzles 8th provided, whose atomizer heads via the supply lines 9a as well as those with one pump each 10 provided central supply lines 9b with a storage vessel 11 are connected.

Furthermore, the coating device has 1 via a control unit, not shown here, which both by means of a pump 10 the amount of over the nozzles 8th to the storage devices 5 fed coating agent and the rotational speed of the applicator rolls 3 controls. Preferably, the control device is equipped with three regulators, via which the rotational speed of the rollers 3 , the feeding times of the nozzles 8th and the feed stream of coating agent to the die heads 8th can be adjusted continuously. Of course, it is also possible to provide a control device which, depending on the predetermined thickness of the on the substrate 2 To be applied coating automatically the rotational speed of the rollers 3 and the coating agent supply stroke of the nozzles 8th regulates. In principle, the greater the desired thickness of the coating to be applied, the longer the given speed of application of the applicator rolls 3 the feed clocks of the nozzles 8th or the larger the nozzles 8th supplied stream of coating agent. alternatively or additionally, it is also possible to increase the amount of coating agent over the distance of the storage devices 5 to the additional rollers 4 to control.

At the first start-up of the coating device 1 becomes the storage vessel 11 filled with the coating agent, preferably a wax-containing silicone oil emulsion, and turned on the control unit, which via an electrical signal drive the applicator rolls 3 and thus controls their rotational speed. By the rotation of the applicator rollers 3 become the respective adjacent intermediate rolls 4 also set in rotation. The pump 10 promotes via the supply lines 9a . 9b Silicone oil emulsion from the storage vessel 11 over the nozzle heads 8th in the two storage devices 5 made of felt, in which the coating agent is absorbed. As soon as the rivers storage capacity of the storage devices 5 is exceeded, the coating agent from the storage devices 5 on the intermediate rolls 4 and from there to the applicator rollers 3 transfer. The latter in turn bring the coating agent onto the substrate 2 on. The control unit also controls the supply flow of coating agent to the nozzles 8th and / or the feed clock times of the nozzles 8th , thereby ensuring that the surfaces of the applicator rolls 3 depending on their rotational speed always with that for achieving the desired layer thickness on the substrate 2 required amount of coating agent are wetted.

It is with the device according to the invention 1 of course also possible, at the same time two or more different coating agents on the substrate 2 apply. In this case, the device points 1 two or more pre-storage containers 11 and a corresponding number of central supply lines 9b on, the latter via supply lines 9a each with some of the nozzles provided 8th are connected. When two coating agents are used, for example, coating agent A is applied to the storage device via the even-numbered nozzles and the coating agent B via the odd-numbered nozzles 5 given up.

1

coater

2

substratum

3

applicator roll

4

intermediate roll

5

memory device

6

bracket

7

drip tray

8th

jet

9a

Jet supply line

9b

central supply line

10

pump

11

Storage jar

Claims (24)

Process for coating a sheet-like substrate ( 2 ), in particular paper, adhesive paper, cardboard, textiles or films, with a coating agent, in particular with a silicone oil emulsion, in which the coating agent is applied by means of at least one application device (US Pat. 3 ) on the substrate ( 2 ) is applied, characterized in that the coating agent by means of a metering device ( 8th ) to at least one memory device ( 5 ) from sponge-like, moisture-storing material and from there optionally via an intermediate device ( 4 ) to the at least one order device ( 3 ) is transmitted. Method according to claim 1, characterized in that the at least one memory device ( 5 ) consists of felt, pulp, sponge rubber, fleece or foam. Method according to claim 1 or 2, characterized in that the material of the memory device ( 5 ) has a mean pore size of 1 .mu.m to 1 mm, more preferably from 50 .mu.m to 750 .mu.m, and most preferably from 100 to 200 .mu.m. Method according to one of the preceding claims, characterized in that the coating means by means of two, seen from the substrate, from each other oppositely arranged applicators ( 3 ) on both sides of the substrate ( 2 ) is applied, wherein the coating agent the two applicators ( 3 ) optionally via an intermediate device ( 4 ) each of a storage device ( 5 ) of sponge-like, moisture-storing material onto which the coating agent is applied via a metering device ( 8th ) is fed continuously or discontinuously, is supplied. Method according to one of the preceding claims, characterized in that the at least one metering device ( 8th ) one or more nozzles ( 8th ). A method according to claim 6, characterized in that the at least one metering device ( 8th ) one or more atomizer nozzles ( 8th ). Method according to one of the preceding claims, characterized in that as an application device ( 3 ) A roller, more preferably a roller with a lateral surface of rubber, metal or steel, is used. Method according to one of the preceding claims, characterized in that as an application device ( 3 ) A roller is used with a smooth outer surface. Method according to one of the preceding claims, characterized in that as intermediate device ( 4 ), a roller, particularly preferably with a lateral surface of rubber, metal or steel and very particularly preferably with a lateral surface of a chromium alloy, is used. Method according to one of the preceding claims, characterized in that as substrate ( 2 ) Paper, adhesive paper or cardboard is used. Method according to one of the preceding claims, characterized in that as Be coating agent is at least one wax-containing silicone oil emulsion is used. Method according to one of the preceding claims, characterized in that a paint and / or Odorants containing silicone oil emulsion is used. Method according to one of the preceding claims, characterized in that the substrate ( 2 ) is used in the form of a web. Device for coating a sheet-like substrate ( 2 ), in particular of paper, adhesive paper, cardboard, textiles or films, with a coating agent, in particular for carrying out a method according to one of claims 1 to 13, comprising at least one application device ( 3 ) for applying the coating agent to the substrate ( 2 ) and at least one metering device ( 8th ), characterized in that it further comprises at least one memory device ( 5 ) of sponge-like, moisture-storing material, which with the at least one application device ( 3 ) possibly via an intermediate device ( 4 ) is connected in a fluid-transmitting manner and the at least one metering device ( 8th ) is arranged such that from this coating agent to the memory device ( 5 ) can be abandoned. Apparatus according to claim 14, characterized in that the at least one memory device ( 5 ) consists of felt, pulp, sponge rubber, fleece or foam. Apparatus according to claim 14 or 15, characterized in that the material of the memory device ( 5 ) has a mean pore size of 1 .mu.m to 1 mm, more preferably from 50 .mu.m to 750 .mu.m, and most preferably from 100 to 200 .mu.m. Device according to one of the preceding claims, characterized in that the device ( 1 ) two order ( 3 ), Additive- ( 4 ), Storage- ( 5 ) and metering devices ( 8th ), the two applicators ( 3 ), from the substrate ( 2 ) seen opposite each other on both sides of the substrate ( 2 ), both applicators ( 3 ) each with an additional device ( 4 ), the additional facilities ( 4 ) each with a memory device ( 5 ) and the memory devices ( 5 ) each with a metering device ( 8th ) are connected fluid-transmitting. Device according to one of the preceding claims, characterized in that the at least one metering device ( 8th ) one or more nozzles ( 8th ). Device according to one of the preceding claims, characterized in that the at least one metering device ( 8th ) one or more atomizer nozzles ( 8th ). Device according to one of the preceding claims, characterized in that the at least one application device ( 3 ) comprises a roller, particularly preferably with a lateral surface made of rubber, metal or steel and very particularly preferably with a smooth lateral surface. Device according to one of the preceding claims, characterized in that it comprises at least one intermediate device ( 4 ), which preferably comprises a roller, particularly preferably a roller with a circumferential surface made of rubber, metal or steel and very particularly preferably with a lateral surface made of a chromium alloy. Device according to one of the preceding claims, characterized in that it comprises a control unit which controls the rotational speed of the at least one application device ( 3 ) and / or the feed cycle times of the at least one metering device ( 8th ) and / or the feed stream of coating agent via the metering device ( 8th ) controls. Coated sheet-like substrate available with a method according to one of claims 1 to 13. Coated sheet-like substrate according to claim 23, characterized in that as a coating agent a silicone oil emulsion is used.