EP2007946B1 - Method for producing a non-slip coating - Google Patents

Description

The invention relates to a process for the production of an antislip coating on a roll-formable or sheet-shaped carrier, in particular for improving the processing properties of the carrier for subsequent processing steps, wherein a cover layer of slip-resistant material is applied to at least one of the two surfaces of the carrier, according to Preamble of claim 1.

Processes of this type are used in particular when web-shaped or sheet-shaped materials are fed to subsequent automated plant sections in which further processing takes place. In particular, a printing process can be involved, in which the carrier is provided with a single- or multi-colored printing layer. An example of an application would be, for example, the production of a packaging material, for which at first a carrier, for example a paper web, is unwound from a supply roll and printed in one or more colors before it is finally fed to further processing steps such as cutting or gluing operations, or even just storage. For a trouble-free processing of the paper web, it is necessary for this that the paper web has certain processing properties, such as a surface texture, which ensures good handling in mostly automated transport and processing processes. Thus, for example, the paper web is provided with a cover layer of anti-slip material to increase the coefficient of friction, hereinafter also referred to as friction coefficient or slip angle, of the wearer. Various anti-slip materials are known, such as paints, which are applied in liquid or pasty form on one or both surfaces of the carrier and must subsequently harden or dry out before further processing of the carrier can take place. In order to achieve the best possible friction properties, according to the prior art, the entire surface to be coated of the Carrier provided with a cover layer. This also appears advantageous because this cover layer protects underlying print layers from abrasion of paint, and also gives the material an optically appealing gloss.

The anti-slip materials used for the coating, however, are expensive, so that the advantage of improved processing properties is associated with higher costs. In addition, paints applied over the entire surface can often be very poorly adhered to planned splices, since the adhesive can be poorly connected to the covering layer. Therefore, it is often attempted to provide the wearer at the planned splice with a cover layer. However, it must be ensured in this case that the usually automated gluing done exactly at these recessed surface areas of the carrier, which sometimes causes difficulties. This in turn leads to higher costs, higher complaint risk, and higher waste risk. Finally, the drying time required after application of the cover layer reduces the overall processing speed. Measures for a faster drying, such as an increase in the drying temperature, in turn entail higher energy expenditure.

In the DE 203 02 310 U1 It is proposed to facilitate the use of everyday goods, such as writing or other documents, blankets as documents for place settings on dining tables and the like, by preventing slippage of these objects on a substrate. This is achieved by using a polypropylene adhesive material as anti-slip material which has residual tack after curing. The adhesive material is applied as a surface pattern.

In the DE 202 06 101 U1 an antislip device is proposed for application on solid ground, in which an anti-slip coating is laminated on a signal band transparent.

In the DE 202004017840 U1 a plastic sheet is described which comprises a planar, flexible plastic carrier, and a plastic coating applied to the coating of plastic, wherein the coating forms a structured surface.

The DE 199 38 828 A1 describes a paper or plastic bag with anti-slip coating of a grid-like or planar coating with a plastic material having a comparatively high coefficient of friction. The order of the coating can be single-point or grid-like manner. The aim of the anti-slip coating is to avoid the slipping of palletized stacks.

The JP 03241092 describes a method for producing a slip-resistant coating on corrugated cardboard using a lacquer layer. The goal of such a coating is again an improved shelf life of the material.

Also the US 4,421,805 refers primarily to improving the stackability of transport sacks by preventing their mutual slippage by means of a layer based on a polyamide resin. This layer can be applied over the entire surface or even in the form of a grid.

The DE 203 11 507 U1 relates to flat, non-slip material in the form of mats or rolls, which is intended as a backing for securing heavy goods. The coating should not be tacky, which is achieved by applying a slightly tacky film-forming organic monomer or polymer in the form of a suspension or paste of "expandable microcapsules" in a solution, suspension or emulsion of the monomer or polymer to the mats becomes. The mats are initially available in the form of endless rolls, which after the coating accordingly be tailored. The coating is preferably partial area, for example in the form of strips.

The EP 1 407 831 A2 is concerned with the production of sealing wax layers on films or film composites, for example by means of gravure printing. The films can also be made of paper, and serve as for the production of a flexible packaging material. Furthermore, systems for such a packaging material are described, in which an unwinding device, a laminating station, a printing station, a Drucküberlackbeschichtungsstation, a sealing layer station and one of these after orderly Aufwickelstation be used. The EP 1 407 831 A2 proposes, with regard to the sealing layer station, a method for producing a partial-surface sealing layer by means of electrostatic coating methods.

It is therefore the object of the invention to provide methods which avoid these disadvantages. Furthermore, it would be desirable if the coefficient of friction of the sheet or sheet material could be optimized for the particular subsequent processing operation, which is currently only possible by using different slip resistant materials, or by using a slip resistant material with e.g. varying viscosity, would be conceivable. These objects are achieved by the features of claim 1.

Claim 1 relates to a method for producing a slip-resistant coating on a roll-formable or arcuate carrier for improving the frictional processing properties of the carrier for subsequent processing steps, such as cutting, punching or folding processes, wherein on at least one of the two surfaces Carrier a cover layer of paint is applied, which is printed only over part surfaces of the surface of the carrier, and before applying the cover layer is a one- or multi-color printing on the surface of the carrier. According to the invention is provided that the cover layer is applied in a grid shape. It has surprisingly been found that the slip angle of a material compared to a full-surface coating with the cover layer is substantially higher when the coating of the surface is not entirely. Thus, not only the slip angle can be increased, which is often a multiple request of the packaging industry, for example, but at the same time also expensive material for the production of the covering layer can be saved.

In detail, Applicant's observations indicate that the slip angle initially increases from full surface coverage of the support when the coverage ratio, that is the ratio between the areas covered by the cover layer and the total area of the surface of the support concerned, is from 100% to lower percentages is reduced. Upon further reduction of the cover ratio, a maximum value of the slip angle which is greater than the slip angle with full-surface coating is finally passed through. After passing through this maximum value, finally, the expected behavior sets by the slip angle decreases, the smaller one selects the faces of the surface of the carrier, which are provided with the cover layer. At a certain masking ratio, ultimately the same slip angle will arise as with the completely covered surface. In this situation, however, there is already a considerable saving in slip-resistant material for the cover layer. As the coverage ratio is further reduced, the slip angle eventually falls below that value and subsequently decreases more and more until it reaches the value corresponding to the slip angle of the uncoated substrate.

The subsequent processing steps mentioned in claim 1 may be steps for processing the coated carrier, such as cutting, punching or folding processes.

For grid-like application of the covering layer, there are several methods of printing technology which are well-known to the person skilled in the art and with which the slip-resistant material can be applied to the surface of the support in the form of a grid. By varying the grid, the above-mentioned cover ratios can be ensured, as will be described in more detail. The masking ratio is also referred to below as a "percentage of the grid" in the context of a grid.

Claim 2 exploits the observation that by varying the cover ratio of the slip angle of the material can be selectively changed. Namely, according to claim 2, the ratio between the partial areas covered by the covering layer and the total area of the respective surface of the carrier is selected depending on the desired friction value (slip angle) of the surface. Thus, the friction value of the web or sheet material can be adjusted to the respective subsequent processing operation.

Claim 3 provides that the layer thickness of the covering layer is selected as a function of the desired friction value of the surface. If, for example, the impression of a closed covering layer is necessary for the sake of gloss, then one can choose the covering ratio higher, but at the same time reduce the layer thickness. So you can get the visual impression of a closed cover layer, but still achieve a significant saving due to the reduced thickness.

Claim 4 proposes to use as support paper, cardboard, textiles, aluminum foils, plastic films or composite films of at least two of the aforementioned materials.

• Fig. 1 einen schematischen Querschnitt entlang der Linie A-A von Fig. 4 eines Abschnittes eines erfindungsgemäßen Werkstoffes bestehend aus einem Träger, einer Druckschicht und einer Abdeckschicht,
• Fig. 2 eine schematische Darstellung des Werkstoffes von Fig. 1 von oben gesehen für ein erstes Abdeckverhältnis,
• Fig. 3 eine schematische Darstellung des Werkstoffes von Fig. 1 von oben gesehen für ein zweites Abdeckverhältnis, und
• Fig. 4 eine schematische Darstellung des Werkstoffes von Fig. 1 von oben gesehen für ein drittes Abdeckverhältnis.

The invention will be explained in more detail below with reference to the accompanying drawings. This show the

• Fig. 1 a schematic cross section along the line AA of Fig. 4 a section of a material according to the invention consisting of a carrier, a printed layer and a covering layer,
• Fig. 2 a schematic representation of the material of Fig. 1 seen from above for a first covering ratio,
• Fig. 3 a schematic representation of the material of Fig. 1 seen from above for a second covering ratio, and
• Fig. 4 a schematic representation of the material of Fig. 1 seen from above for a third covering ratio.

In the Fig. 1 is a schematic representation of a material according to the invention shown, which consists of a support 1, optionally a printing layer 2, and a cover layer 3. The carrier 1 may be, for example, a paper web, a paper sheet, a cardboard, a textile, an aluminum foil, a plastic foil, a composite foil of at least two of the aforementioned materials or the like. In any case, the carrier 1 is unwound from a roll or arcuate, and is thus suitable to be fed in the course of automated processing processes subsequent processing steps.

The print layer 2 can also consist of several color layers, for example if several color planes are applied in the course of printing on the carrier 1.

As already mentioned, it is necessary for a trouble-free processing of the carrier 1 in subsequent processing steps that the carrier 1 has certain processing properties, such as a surface finish, which ensures good handling in mostly automated transport and processing processes. Therefore, the carrier 1 is provided with a cover layer 3 of anti-slip material to increase the coefficient of friction of the carrier 1. In the Fig. 1 is shown approximately that only the upwardly oriented surface of the carrier 1 or the printing layer 2 is provided with a covering layer 3, but not the downwardly oriented surface of the carrier 1. However, both surfaces of the carrier 1 with a printing layer 2 and / or or a cover layer 3 may be provided.

Various anti-slip materials are known, such as paints, which are applied in liquid or pasty form on one or both surfaces of the carrier 1, and subsequently harden or dry before further processing of the carrier 1 can take place. These paints are colorless, glossy or matt-drying materials, which are applied either as a printing varnish by the printing press, or as an aqueous-based dispersion varnish by a separate printing varnish, on the support 1 and the print layer 2. In the context of printing processes, varnishing usually represents the last printing phase and not only improves the appearance of a printed product, but also increases the abrasion resistance of the printing inks of the printing layer 2, especially with matt paper. Not least, these varnishes also have an anti-slip effect. which is exploited in the case of a subsequent processing of the printed product. In a conventional manner, the entire surface of the carrier 1 to be coated is provided with a covering layer 3 in order to achieve the best possible friction properties. The cover layer 3 also has the purpose of protecting the underlying print layer 2 from abrasion of paint.

According to the invention, however, it is provided that the covering layer 3 is applied only over partial surfaces of the surface of the carrier 1. As already mentioned, the slip angle of a material is significantly higher in comparison to a full-surface coating with the cover layer 3, if the coating of the surface is not entirely done. In a preferred manner, the application of the cover layer 3 is approximately grid-shaped, wherein the shape of the grid is in principle immaterial. Depending on the application, different raster shapes may prove suitable wherein the selection of the optimal grid shape represents a common task for the skilled person. By varying the grid different Abdeckverhältnisse can be ensured. In the Fig. 2 to 4 is a simple example of a grid shown, which consists of individual grid points 4, which are arranged in a regular arrangement over the surface 5 of the carrier 1 and the printing layer 2. A raster point 4 is a printable image element which can be applied at different distances from each other or in different sizes. That in the Fig. 2 to 4 The grid shown by way of example would correspond approximately to a frequency-modulated raster, ie a raster in which the surface 5 is divided into raster dots 4 of the same size, the variation of the percentage of the raster, ie the coverage ratio, over the number of dots in the area (the frequency ) he follows. The screen dots 4 could also be arranged stochastically. In contrast, the surface 5 could also be divided into a fixed number of halftone dots 4 (eg "24-frame": 24x24 dots per cm ² ) and the variation of the percentage of the grid over the size of the dots (the amplitude) , in which case one also speaks of an amplitude-modulated raster. These two types of grid can also be combined. In the Fig. 2 to 4 schematically a raster form is shown, each with different percentages. In the Fig. 2 is shown as a grid with a relatively low coverage ratio. For example, if 30% of the total surface area of the surface 5 covered with grid points 4, so we speak of a "30% grid". In the Fig. 3 the number of grid points 4 has been increased and represents eg a "50% grid". The Fig. 4 Finally, schematically represents a "70% grid". However, all other types of raster shapes and Abdeckverhältnissen are conceivable.

For the application of the grid point 4 are the expert several well-known methods from the printing available, with which the slip-resistant material applied to the surface 5 of the support 1 in the form of a grid can be. The choice of the optimum printing method will depend on the properties of the substrate 1 or the printing layer 2, the requirements of the subsequent processing steps, the nature of the slip-resistant material, or simply the cost issue. Depending on the application, the person skilled in the art will thus opt for different high-speed, flat, gravure or through-printing methods, such as flexographic printing, offset printing, screen printing or even thermal printing processes. The subject invention can be realized in any case with all these printing methods.

If a carrier 1 made of a specific material is used, for example a paper sheet, then this carrier 1 has, after printing with the printing layer 2, a certain friction value (slip angle). This slip angle is smaller than the slip angle that results in full-surface painting with the cover layer 3. For full-surface, grid-shaped painting with the cover layer 3 is a "100% grid". As already mentioned, starting from such a full-area coating of the carrier 1 or the print layer 2, the slip angle initially increases when the percentage of the grid is reduced, for example to a 70% grid (FIG. Fig. 4 ). With further reduction of the cover ratio, finally, for example, at a 50% grid ( Fig. 3 ) pass through a maximum value of the slip angle, which is greater than the slip angle with full-surface coating. After passing through this maximum value, finally, the expected behavior sets by the slip angle decreases, the smaller one selects the faces of the surface 5 of the carrier 1, which are provided with the cover layer 3. At a certain masking ratio, ultimately the same slip angle will arise as with the completely covered surface. For a 24-grid this would be the case for a 30% grid (schematized in Fig. 2 ). In this situation, however, there is already a considerable saving of slip-resistant material for the cover layer 3 of about 70%. With further reduction of the cover ratio of falls Finally, slip angle below this value and subsequently decreases more and more until it assumes the value corresponding to the slip angle of the uncoated carrier 1 or the pressure layer 2.

By varying the cover ratio, therefore, the slip angle of the painted printing unit can be selectively changed. It is only necessary to choose the ratio between the partial areas covered by the covering layer 3 and the total area of the relevant surface 5 of the carrier 1 as a function of the desired friction value (slip angle) of the surface 5. Thus, the friction value of the sheet or sheet material according to the invention can be adapted to the respective subsequent processing operation.

With the method according to the invention or the material according to the invention, it is thus possible to reduce the amount of slip-resistant material used for the coating, which results in a considerable cost reduction. Furthermore, bonding operations are easier to carry out because, due to the raster, the adhesive, e.g. Glue, a compound to the carrier 1, e.g. Paper, build, and so can achieve the necessary adhesive properties. This in turn leads to lower costs, as well as lower complaints and spoilage. Finally, due to the smaller amounts of material required for the cover layer 3, the required drying time can be reduced, which increases the overall processing speed. Measures for faster drying, such as an increase in the drying temperature or the like, are no longer or to a reduced extent necessary.

Claims (4)

1. Method for producing a non-slip coating on a carrier (1) which is in the form of a sheet or can be unwound off a roll, for improving the friction-related treatment characteristics of the carrier (1) for subsequent treatment steps, such as for example cutting, stamping or folding processes, a covering layer (3) consisting of lacquer being applied to at least one of the two surfaces (5) of the carrier (1), the lacquer being printed on only over partial areas of the surface (5) of the carrier (1), and prior to the application of the covering layer (3), a single-coloured or multicoloured printing process takes place on the surface (5) of the carrier (1), characterised in that the covering layer (3) is applied in the form of a grid.
2. Method according to claim 1, characterised in that the ratio between the partial areas covered by the covering layer (3) and the total area of the respective surface (5) of the carrier (1) is selected as a function of the desired friction value of the surface (5).
3. Method according to one of claims 1 to 2, characterised in that the layer thickness of the covering layer (3) is selected as a function of the desired friction value of the surface (5).
4. Method according to one of claims 1 to 3, characterised in that the carrier (1) used is paper, cardboard, a textile material, an aluminium foil, a plastics material film, or a composite sheet made of at least two of the aforementioned materials.

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