Device for satinizing and embossing packaging foils

p0001The present invention relates to a device for satinizing and embossing packaging foils having at least three embossing rolls, according to the preamble of Patent Claim first

p0002However, it is also possible to provide an apparatus with two embossing rolls, such as according to the preamble of claim 2nd

p0003Such devices are known from <patcit id="pcit0001" dnum="EP1372946A"><text>EP-A-1372946</text></patcit> known of the same Applicant. The European patent application is a further development of the device according<patcit id="pcit0002" dnum="US6715411B"><text>US-B-6715411</text></patcit> of the same applicant. Two devices defined therein is common that the paper web first a first pair of rolls and then a second pair of rollers passes through, wherein the contact pressure is reduced by the use of three rollers and a better breaking of the paper portion of the film can be achieved.

p0004The surface structures of the embossing rolls, that is, the arrangements of the teeth, circular ribs or longitudinal ribs on the known rollers, the paper break symmetrical, whereby compared to the previously known prior art homogeneous refraction of the fibers results in two directions, and thereby finer embossings can be achieved , wrinkling in the logo area is prevented, a reduced tendency to tubing and curling can be found and good folding properties, or so-called Deadfoldeigenschaften, can be achieved.

p0005There are, however, appeared more problems with the slides on paper pad lately. The following are some of these issues are given that result from different, more recent paper properties:<ol><li>a) An influential and difficult to control component is the non-uniformity of the texture of the film, called in the cigarette industry innerliner, where the difficulties result from the fact that the variety of commercially available innerliner papers constantly increasing, without any unifying tendencies are visible. This means that depending on the region or requirements from the marketing area papers with a basis weight of 30 g / m² to 80 g / m²Metalized aluminum-laminated or surface-treated, for. Example, by printing in order to obtain a metal-like surface may be used. In the application of so-called shadow embossed, see for example<patcit id="pcit0003" dnum="US7036347B"><text>US-B-7036347</text></patcit> of the same applicant, very fine structures are produced, the material must be marked with the same quality regardless.</li><li>b) The mechanical properties of the films are strongly influenced by the pulp fibers, their morphological characteristics and their processing employed. therefore Outwardly similar films can differ greatly in their mechanical behavior. Considering this, it is desirable to obtain good results with inner liners of poor quality.</li><li>c) it is desirable for the industrial stamping of different films, to reduce dependence on their broad sensitivity range.</li><li>d) Another economic challenge is films of varying quality to shape such that visually distinguishes this when viewing similar embossed characters barely. same impressions can be very different in the present state of the art in both logos as well as shadow imprints on the eye, depending on the nature of the film.</li></ol>

p0006It is from this prior art, starting object of the present invention to provide a device for satinizing and embossing foils, with which the fibers of the paper backing of the film are more effectively broken, to give an aesthetically better overall picture after embossing, the practically independent is the nature of the paper backing of the film and to enable the proper embossing of fine structures. Such a device is defined in claim 1 or claim 2nd Further objects and advantages are defined in dependent claims.

p0007The invention is explained in more detail below with reference to drawings of exemplary embodiments.<dl id="dl0001"><dt>Fig. 1</dt><dd>shows, schematically and in a perspective view a device with an embossing roll having a homogeneous array of teeth which cooperates with two further embossing rollers,</dd><dt>Figures 2-5</dt><dd>each show a structure of the other two embossing rolls, in an enlarged detail,</dd><dt>Fig. 6</dt><dd>shows a variant of the structures of the further embossing rollers,</dd><dt>Figures 7 and 8</dt><dd>show further embodiments of the structures of the other embossing rollers, </dd><dt>Fig. 9</dt><dd>schematically shows a section through the three unsynchronised embossing rolls,</dd><dt>Fig. 10</dt><dd>schematically shows a section through the three synchronized embossing rolls,</dd><dt>Fig. 11</dt><dd>shows an enlarged detail of teeth of the first embossing roll with macro- and microstructures,</dd><dt>Fig. 12</dt><dd>shows in a still larger scale, different possible microstructures of the tooth surface of <figref idrefs="f0005">Fig. 11</figref>.</dd><dt>Fig. 13</dt><dd>shows a variant of <figref idrefs="f0005">Fig. 11</figref>With macro-structures and microstructures on the teeth, and</dd><dt>Fig. 14</dt><dd>shows a second embodiment of the invention, with two embossing rollers.</dd></dl>

p0008In the schematic representation of <figref idrefs="f0001">Fig. 1</figref> three embossing rolls R1, R2 and R3 shown, the embossing roll R1 is driven by a drive. 4 The embossing roll R1 is known per se and have been disclosed in various patents, also in the input documents cited. The driven embossing roll R1 has a surface structure with both axially and circularly homogenous grid individual teeth 5 by means of which the Satiniereffekt is achieved. This surface structure is called the basic grid GR. The teeth can pyramidal with different cross-sections may be formed as truncated pyramids or conical. In the case of pyramid-shaped teeth, these have a cross section in the form of a tetragonal parallelogram.

p0009The other two embossing rollers R2 and R3 can over the film 9 and by means of suitable surface structures by the first embossing roll R1, see <figref idrefs="f0004">Fig. 9</figref>are driven or by a known synchromesh 6, 7 and 8, see <figref idrefs="f0004">Fig. 10</figref>, In general, the film 9 is so guided by the embossing rolls, that the metallized or treated surface shows against the first embossing roll R1.

p0010However, it is also possible, instead of 2 or 3 to drive 1 embossing roller embossing roller and let the other embossing rollers run free. Instead synchronization via gears and a synchronization means of belts or electronic means is possible.

p0011In papermaking, the so-called flocculation is a key operation, which is that fiber suspensions exhibit a natural Flockungstendenz. This increases with increasing concentration of the fibers, resulting in an increase in consistency resulted. The observed in many innerliners density Faserflockung gives the paper a relatively high strength. The flakes are very unevenly distributed uniformly over the paper surface and it can no homogeneous, fine screen structures are achieved.

p0012Investigations have shown that the film with a uniform set of teeth by the embossing process in the running direction, ie in the longitudinal direction, tends to be shortened and slightly broadened in the transverse direction. This effect can be explained by the fact that the cellulose fibers are mainly aligned longitudinally. By crushing the fibers attract these naturally in width and only to a limited extent at length.

p0013To counteract this tendency, the surfaces were each embossing roll homogeneously with similar elevations and depressions according to prior art - provided, for example with pyramid-shaped teeth of different cross-sections such as quadrangle parallelograms, truncated pyramids or conical teeth, so that - with the basic screen. interaction with the other involved in the embossing process the embossing rolls is possible.

p0014Asymmetric structure elements in each, consisting of the same basic grid teeth were avoided in order to counter distortion of the embossed image. There were tested lately various alternatives to cope with the demands that have been placed by the different types of paper and paper grades.

p0015Investigations have shown that arranged through the use of embossing rollers with different structural elements, such as sprockets, circular, helically or along the embossing roller teeth whose height the same as that of the basic grid GR of the first embossing roll is not a very large improvement in the refractive, or neutralization of the by flocculation substructures of the paper backing was achieved. This can be explained by that, are better suited for the removal of randomly formed flakes, structures of the roller surface, which does not have the same basic grid GR. This applies both for the three-as well as for the two-roll arrangement.

p0016By using the rollers described below not only a better refraction and neutralize the paper backing with respect to wrinkling, tubing and curling is achieved, but in particular also an aesthetically much improved surface of the film, which gives this a sophisticated look. Finally allowed such a surface of the film a finer and more precise embossing of very fine structures, used in the manufacture of authentication and identification features, for example.

p0017As from <figref idrefs="f0004">Fig. 9 or 10</figref> apparent, the film 9 passes through the first pair of rollers R1 and R2 and then the roller pair R1 and R3. It follows that the film first passes through the assembly of different structures of a pair of rollers, and then by the surface structure of the second roller pair arrangement differently, ie to be treated inhomogeneous, resulting in a completely non-homogeneous treatment of the film, the surprising results shows.

p0018In <figref idrefs="f0001">Fig. 1</figref> is, as already mentioned, the embossing roll R1 provided with homogenous grid individual teeth 5 defining the basic grid GR. It may be pyramidal or conical teeth, which have a per se known flattening of min. 2%, preferably at least 5%, wherein the cross section of the pyramidal teeth has the shape of a quadrilateral parallelogram.

p0019In <figref idrefs="f0001">Fig. 1</figref> are also the surface structures of the embossing rollers R2 and R3 by the letters A - Z symbolizes - J, and Q, respectively. When comparing<figref idrefs="f0001">Fig. 1</figref> With <figref idrefs="f0001">FIG. 2</figref> It can be seen that the designation R2A denotes the surface structure of the embossing roller A R2, and R3Q the surface structure Q on embossing roll R3, etc.

p0020In <figref idrefs="f0001">FIG. 2</figref> is a possible surface structure of the embossing rolls specified R2 and R3. The surface structure of the roll surface A of R2 according<figref idrefs="f0001">FIG. 2</figref> is defined by longitudinal ribs 10, which are interrupted by thunderstorms structural elements in the form of rows of teeth 11, with the row of teeth 11 is composed of individual teeth 5 and the teeth have in the present example, a truncated pyramid-shaped design. The surface of R2, therefore, does not consist of uniform longitudinal ribs, as known from the prior art, but from the longitudinal ribs, which are interrupted by circular rows of teeth, wherein the height of these structural elements is not the same as the basic grid GR.

p0021The structure Q of the third embossing roll R3 here consists of uniformly arranged circular ridges 12, as in accordance with embossing rolls prior art is known per se.

p0022The longitudinal, transverse or helical structure elements have a cross section which tapers towards the outside and has a flattened portion, wherein the dimensions of the structural elements and the intermediate grooves correspond to the dimensions of the teeth 5 of the first, driven embossing roll R1, wherein all of the teeth engage into the grooves between the ribs.

p0023In <figref idrefs="f0002">Fig. 3</figref> it is shown that the surface structure B of the embossing roller R2 having the interrupted longitudinal ribs 10, and double rows of teeth 13, it being understood that there can be three or more rows of teeth, which interrupt the longitudinal ribs 10th The embossing roll R3 has the same surface structure as Q according<figref idrefs="f0001">FIG. 2</figref> on.

p0024In <figref idrefs="f0002">Fig. 4</figref> it is shown that the embossing roll R2 the same surface structure as according to A <figref idrefs="f0001">FIG. 2</figref> comprising, while the embossing roller R3, a surface structure comprising R wherein circular ribs 14 are interrupted by longitudinally disposed rows of teeth 15, the tooth rows of individual teeth 5 are made.

p0025In the illustration according to <figref idrefs="f0003">Fig. 5</figref> , the embossing roll R2 the surface structure B as in <figref idrefs="f0002">Fig. 3</figref> , while the embossing roller R3, a surface structure S, whereby the circular ribs 14 are interrupted by a double longitudinal rows 16, whereby these rows are composed of individual teeth fifth

p0026Already from the description of <figref idrefs="f0001 f0002 f0003">Figures 1 to 5</figref> it appears that a wide variety of variations are conceivable. Thus, it is of course possible to provide not only structural elements in the form of single or double rows of teeth, but also triple or multiple rows of individual teeth, between which the longitudinal or circular ribs are arranged.

p0027Moreover, it is understood that both the dimensions of the individual teeth and the spaces between the rows of teeth and the longitudinal or circular ridges may vary in their dimensions and intervals, provided that they are dimensioned and arranged such that they are always engaged, or with the rasterized teeth of the embossing roll R1 can be brought rollingly. Of course, any combination of the indicated types of rolls of the two embossing rolls is possible.

p0028While in the <figref idrefs="f0001 f0002 f0003">Fig. 1 - 5</figref> Surface structures are shown, in which the structural elements are arranged orthogonally to the longitudinal axis of the rollers are in the <figref idrefs="f0003">Fig. 6</figref> and <figref idrefs="f0004">8th</figref> Surface structures illustrated in which the existing of individual teeth or continuous rib structure elements are arranged helically.

p0029In <figref idrefs="f0003">Fig. 6</figref> is for the embossing roll R2 has a surface structure G shown in which, in the longitudinal ribs 10 as according <figref idrefs="f0003">Fig. 5</figref> Structural elements 17 helically and, for example, are arranged at an angle of 45 ° to the longitudinal axis, which in turn consist of rows of teeth with individual teeth fifth

p0030The counter roll R3 has a surface structure X, which is a mirror image of the structure G, but structural elements 18 of two rows of teeth 5 and at an angle of, for. Example, 45 ° to the longitudinal axis of the embossing roller are arranged. As in the<figref idrefs="f0002">FIGS. 3, 4</figref> and <figref idrefs="f0003">5</figref> shown, the embossing roller R3 with surface structure X likewise rings 12, which are broken by the structural elements of the eighteenth

p0031In <figref idrefs="f0004">Fig. 7</figref> is for embossing rolls R2 a surface structure H illustrated, the structure elements are not made of rows of individual teeth, but out of circular ridges 19, wherein the distances between the individual fins is variable and no longitudinal ribs are present. The embossing roll R3 has the surface structure of Y consisting of longitudinal ribs 20th Here too, results in the interaction of the embossing rollers R2 and R3 is a non-homogeneous refractive the paper fibers.

p0032according to the embossing rolls <figref idrefs="f0004">Fig. 8</figref> are analogous to the embossing rolls in accordance with <figref idrefs="f0003">Fig. 6</figref> to see by being provided as structural elements helically disposed ribs 21, but without intervening longitudinal or transverse ribs, the spacings between the individual ribs can be variable, too. The ribs 22 of the embossing roller R3, which result in the surface structure Z are arranged in this example, close to tightly and helically. Here is a cooperation of the two embossing rolls R2 and R3 is a non-homogeneous characteristics and thus a maximum refraction of the paper fibers.

p0033Based on these embodiments, a very large number of variations are possible, both in terms of the distances between the individual webs and with respect to the angle of the circumferential webs. Combinations of the types illustrated are possible, ie that individual by circular, longitudinal or helical paths can consist of individual teeth. Moreover, it is for a skilled person that the teeth do not necessarily have to be rectangular or square pyramids, which are flattened at the top, it can also conical, preferably flattened teeth, be.

p0034In certain paper grades only a two-roll device it is sufficient, according to <figref idrefs="f0006">figure 14</figref> to use. Analogously are all surface structures previously described for the two-roll device, the driven embossing roll R31 having a basic grid GR1, which is the basic grid GR analog. The teeth 35 have as a variant to a rhombic cross section and the sides with respect to the longitudinal axis can be at an arbitrary angle beispielswe, ise be arranged rotated by 45 °. This results in a good synchronization of the two rolls.

p0035The second roller R2 always has a non-homogeneous surface structure, such as according to A, B, G, H, Y; R, S, X. The second roll, if the first embossing roll comprises a toothing as with R1, either driven by the shaping of the teeth and ribs over the film or by synchronizing means.

p0036The embossing rollers described and illustrated are, as shown, suitable for the optimum satining packaging foils, in particular of cigarette paper. If logos are desired, these are, as known from the prior art, preferably mounted on the embossing roll R1 to the basic grid GR or GR1. This is done by, teeth are removed at the point where the logo is to be built, so that the metallized or treated surface of the film, which comes to lie there, is not changed during the passage and remains shiny.

p0037As mentioned above input, the surface of which is particularly fine by the treatment of the film according to the invention, so in addition to logos authentication and identification features can be influenced, which are particularly tamper-proof and have a very fine structure. In addition to these surface structure is also particularly suitable for so-called shadow embossing which will be described.

p0038Authentication and identification features and shadow imprints can eg according <patcit id="pcit0004" dnum="US7036347B"><text>US-B-7036347</text></patcit> of the same applicant are produced or by means of embossing rolls, which in the <patcit id="pcit0005" dnum="EP1437213A"><text>EP-A-1437213</text></patcit> are disclosed by the same applicant.

p0039In the <figref idrefs="f0005">Figures 11 - 13</figref> is an example of an in <patcit id="pcit0006" dnum="EP1437213A"><text>EP-A-1437213</text></patcit> Macro-structure and micro-structuring said surface processing of the individual teeth and of the tooth bottom of the driven embossing roll R1 is shown.

p0040In <figref idrefs="f0005">figure 11</figref> are six teeth 5S1 to 5S6 drawn, wherein the microstructures are shown hatched. The teeth are truncated pyramid with a rectangular ground plan, with the side edges parallel, and aligned perpendicular to the longitudinal axis of the roll and the pyramids are flattened.

p0041Tooth 5S1 has a microstructure 20 on the flattened portion of the tooth as well as a microstructure 21 on one or both transversal sides of the tooth, and tooth 5S4 has the same surface structure 20 and a microstructure 22 on one or both longitudinal side ( n) on the tooth. The tooth base ZG, a microstructure 23 having along the longitudinal side of the teeth or with a microstructure 24 on certain lengths or with a microstructure 25 transverse thereto.

p0042Tooth 5S2 has on one or both longitudinal sides with a microstructure 26 that extends over the whole page, and tooth 5S3 has a microstructure 27 that extends over the whole surface of the flattened portion. The teeth 5S5 exhibit only narrow microstructure 28 on the amount of long side, while tooth 5S6 is unchanged. Assuming can be mounted of course a variety of microstructures that arise as great a variety of patterns on the film.

p0043In the <figref idrefs="f0005">Figures 12A - 12D</figref> are on and given to the teeth a few examples of possible straight or curved microstructures in a stronger magnification. In<figref idrefs="f0005">12A</figref> there is shown a positive grid structure in cross-section, wherein the individual webs 30 have a spacing of a few microns. This structuring may be at any one of microstructures 20, 21, 28 or 29 are, however, also be applied to the tooth surface, eg in the microstructures 23, 24 or 25th

p0044In <figref idrefs="f0005">figure 12B</figref> is indicated a negative grid structure in cross section, the depressions 31 also have a spacing of several 100 nm to several microns of each other.

p0045In <figref idrefs="f0005">figure 12C</figref> indicated in a perspective view a possible positive micro-structure by means of grid-like, curved ridges 32nd

p0046In <figref idrefs="f0005">figure 12D</figref> indicated in a perspective view a possible negative microstructure by means of grid-like, curved grooves 33rd This structure is suitable, for example, to find 24 or 25 use in the microstructure.

p0047It is starting evident from these few examples that a very large range of variation both of microstructures, or distribution of the microstructures on the individual teeth and on the tooth bottom or only on the tooth bottom alone, as well as the nature of the microstructures itself is possible. This depends on the current level of technology for the production from these structures, the production of microstructures, in particular also finds application in the manufacture of electronic chips and known from there. With such fine microstructures, the use of suitable methods such as lacquer or etching techniques plays an important role. Such microstructure produces a diffraction of light when irradiated.

p0048The teeth of <figref idrefs="f0005">figure 13</figref> have both a macro-structure and micro-structuring. Is understood to macro-structure, the change in the tooth geometry, which produces character during embossing, whose appearance changes depending on the viewing angle and / or type and / or location of the illumination source. This geometrically modified teeth shape more or less the metal surface of the film. This macro-structure, a microstructure be superimposed to give special effects to the shadow embossing.

p0049In <figref idrefs="f0005">figure 13</figref> one recognizes three geometrically unmodified teeth 5S1, 5S4 and 5S6, however with microstructures as in <figref idrefs="f0005">figure 11</figref> and geometrically modified teeth 5M1, 5M2 and 5M3, the "M" for macro-structure is. Tooth 5M1 exhibits a greater flattening than a regular tooth such as 5S1, being on the flattened part of a microstructure 20 is attached.

p0050Tooth 5M2 only has a larger flattening and is otherwise unchanged, while the tooth has been 5M3 halved in width. Of course, the teeth 5M2 and 5M3 microstructures exhibit. Also in the embodiment according to<figref idrefs="f0005">figure 13</figref> the tooth can be processed basic and same microstructure 23 as in <figref idrefs="f0005">figure 11</figref> and a microstructure 25 having.

p0051From the representation of <figref idrefs="f0005">figure 13</figref> results in an even greater variety of possibilities for change of teeth in order to obtain a very large variety of embossing patterns. Here also only the structures of the tooth base can be used alone for embossing.

p0052It should be clarified that all the teeth are provided with macrostructures and microstructures to change the metallized or treated surface of the film, in contrast to the tooth gaps at the location of logos, which do not alter the surface of the film.

p0053From the description of the surface structures of the rolls as well as macro-structures and microstructures of the teeth is apparent in that the embossing rollers are made of metal.