WO2008019702A1

WO2008019702A1 - Method and apparatus for producing a decorative multi-ply paper product and such a multi-ply paper product

Info

Publication number: WO2008019702A1
Application number: PCT/EP2006/008124
Authority: WO
Inventors: Ferdinand Hein; Thomas Heilemann
Original assignee: Sca Hygiene Products Gmbh
Priority date: 2006-08-17
Filing date: 2006-08-17
Publication date: 2008-02-21
Also published as: ATE529252T1; ES2371663T3; EP2051846A1; EP2051846B1

Abstract

The idea of the present invention is to provide a decorative embossing which is constituted of at least a first decorative embossing pattern (37) and a second decorative embossing pattern (38). In this context, the protuberances of the first decorative embossing pattern (37) on the embossing roll (31) have a larger height than the protuberances of the second decorative embossing pattern (38) on the embossing roll (31). Correspondingly, the bosses of the first decorative embossing imparted to at least one ply of the multi-ply paper product are larger than the bosses of the second decorative embossing imparted to the at least one ply of the multi-ply paper product. Because of this configuration, glue may only be applied on top of the bosses of the first decorative embossing so that ply bonding is only achieved at these sites or locations by means of the applied adhesive. Therefore, the first design elements corresponding to the first decorative embossing, and the second design elements corresponding to the second decorative embossing, are decoupled. A first design element, therefore, may be adapted to the required glued area in view of the ply bonding to be achieved as well as the properties to be achieved in regard of softness and bulk, etc., whereas the second design elements may substantially freely be varied.

Description

Method and apparatus for producing a decorative multi-ply paper product and such a multi-ply paper product

Technical Field

The present invention relates to the production of decorative multi-ply paper products, particularly tissue paper products and to such products. In particular, the present invention relates to multi-ply paper products having a decorative embossing and in which ply bonding between at least two plies is achieved by means of an adhesive.

Background of the Invention

Multi-ply paper products known in the art are generally used in toilet paper, kitchen towels, hand towels etc. It has become widely spread to provide such paper products with an appealing visual appearance to increase the sales of the products. In this context, design elements were imparted to at least one of the plies by means of embossing. Such an embossing is referred to as decorative or decoration embossing. It may also be referred to as design or decor embossing. The design elements of this embossing may be provided in the form of flowers, feathers, whales, dolphins, logos, trademarks, marks or the like. In addition, these paper products commonly comprise a further embossing imparted to the ply. This embossing may be referred to as background embossing or functional embossing.

Figure 1 depicts such a multi-ply paper product in a plan view. The paper product 10 comprises a decorative embossing in the form of feathers and a functional embossing 12 in the form of minute spots evenly distributed over the entire surface of the paper product. The two plies of the paper product are bonded by means of an adhesive. In particular, the plies are bonded at the locations of the feathers. Such a multi-ply paper product as shown in Figure 1 may for example be produced as described in US 6,287,676 B. In this reference, a functional embossing and a decorative embossing are imparted to the at least one ply of the multi-ply paper product by means of an embossing roll . The bosses of the decorative embossing pattern have a much larger height, i.e. the embossing has a larger depth, than the bosses of the functional embossing. The embossing roll is in contact with a glue application roll, which applies glue only on the top of the bosses of the decorative embossing pattern. Subsequently, the at least one embossed ply is brought together with another embossed ply and ply bonding is achieved at the locations of the decorative embossing bosses by means of the applied adhesive. At the location of the functional embossing bosses, no ply bonding is achieved. Similar methods are, for example, described in US 4,376,671 and US 4, 320,162 B.

The decorative embossing of such a multi-ply paper product has a great influence on the sales, because an appealing appearance does attract more customers. If the visual appearance is distinctive compared to the visual appearance of comparative products, there may even be a re-collection effect that a customer will recognize the paper product he/she bought the last time and will again purchase this product .

However, the possibilities to vary the design or decorative appearance of the paper product and particularly the decorative embossing are limited. This limitation, on the one hand, resides in the fact that such variations ought to be effected on standard machines because more complicated and customized machines compared with such standard machines are more expensive and, therefore, lead to a more expensive product. As such products, however, are disposable products, the costs of manufacture are one major factor for the sales. On the other hand, it is only known in the art to combine the plies at all of the decorative embossing locations by means of an adhesive, i.e. to apply the adhesive to all of the decorative embossing bosses. Hence, there exists the additional problem that the choice of the decorative embossing is closely related to the glued area. The glued area, however, has a large influence on the properties of the product, such as softness and bulk. As a consequence, the decorative embossing pattern is also limited by these properties, which ought not to be jeopardized for improving the visual appearance.

Summary of the Invention

Accordingly, it is the object of the present invention to provide a method and an apparatus for producing a decorative multi-ply paper product which enable a greater design variability by using standard equipment and to provide a multi-ply paper product being more attractive, however, still complying with the requirements regarding its properties, such as softness and bulk.

This object is solved by a method as defined in claim 1, an apparatus as defined in claim 6 as well as a multi-ply paper product as defined in claim 11. Embodiments of the present invention are named in the dependent claims.

The basic idea of the present invention is to provide a decorative embossing which is constituted of at least a first decorative embossing pattern and a second decorative embossing pattern. In this context, the protuberances of the first decorative embossing pattern on the embossing roll have a different height than the protuberances of the second decorative embossing pattern on the embossing roll. In particular, the protuberances of the first decorative embossing pattern are larger than that of the second decorative embossing pattern.

Correspondingly, the bosses of the first decorative embossing imparted to at least one ply of the multi-ply paper product are larger than the bosses of the second decorative embossing imparted to the at least one ply of the multi-ply paper product. I.e. the depth of the first decorative embossing is larger than the depth of the second decorative embossing pattern. Because of this configuration, glue may only be applied on top of the bosses of the first decorative embossing so that ply bonding is only achieved at these sites or locations by means of the applied adhesive. These locations may also be referred to as glue sites. Therefore, the first design elements corresponding to the first decorative embossing, and the second design elements corresponding to the second decorative embossing, are decoupled. A first design element, therefore, may be adapted to the required glued area in view of the ply bonding to be achieved as well as the properties to be achieved in regard of softness and bulk, etc, whereas the second design elements may substantially freely be varied.

The method according to the present invention for producing a decorative multi-ply paper product, particularly a tissue paper product, therefore, comprises the steps of: embossing at least one of the plies by means of an embossing roll having first protuberances to impart a first decorative embossing pattern and second protuberances to impart a second decorative embossing pattern, the first protuberances having a larger height than the second protuberances, applying glue on one side of the at least one ply only at sites corresponding to the tops of the first protuberances, and bringing together the one ply with at least one other ply, whereby ply bonding is achieved at the glue sites . Further, the present invention provides an apparatus comprising a decoration embossing unit having an decoration embossing roll having first protuberances to impart a first decorative embossing pattern to at least one ply and second protuberances to impart a second decorative embossing pattern to the at least one ply, the first protuberances having a larger height than the second protuberances; a glue application unit having a glue application roll being in contact with the decoration embossing roll for applying glue on one side of the at least one ply only at sites corresponding to the tops of the first protuberances; and a marrying roll for bringing together the at least one ply with at least one other ply, whereby ply bonding is achieved at the glue sites.

The multi-ply paper product of the present invention comprises at least two plies, at least one of the plies having a first decorative embossing pattern and a second decorative embossing pattern, the depth of the first decorative embossing pattern being larger than that of the second decorative embossing pattern, the two plies being bonded at the sites of the first embossing pattern only.

The decorative embossing pattern may also be referred to as design embossing. In contrast to a background or functional embossing as known in the art, the decorative embossing pattern may be defined as follows: In the decorative embossing pattern, the technical function which is to be fulfilled by the embossing is always combined with the function to improve the aesthetical appearance addressed to the sensation of a consumer. That is, a decorative embossing pattern in contrast to a background embossing pattern is generally not constituted by mostly small and simple embossing protrusions (dots) which are arranged in a row, but rather constituted of more or less complex shapes and motives or themes, respectively. Such forms or themes may be a particular picture or drawing, a word, and artistic shape, an object, a pictogram or an abstract geometrical arrangement for example. Possible designs are for example plants, animals, clouds, feathers, objects of daily life, scripts, logos, trademarks or marks. Preferably, the decorative embossing pattern is constituted by relatively long, straight (rectilinear) , curved or circular lines preferably having different thicknesses, wherein such lines may also be present in the form of closed structures. The lengths of such lines may be in the range from 0.5 to 10 cm, preferably in the range from 1 to 8 cm. In contrast, the background embossing pattern often comprises relatively small embossing protrusions (dots) having a diameter or an edge lengths of not more than 1 cm, preferably not more than 0.5 cm. Such a background embossing pattern ought to primarily achieve a technical function without addressing the aesthetical sensation of a consumer. The decorative embossing ought to primarily achieve an appealing design.

It is to be understood that, though only two decorative embossing patterns, the first and the second decorative embossing pattern, are named, there may also be provided more than two decorative embossing patterns, all of them having different heights.

In addition to these decorative embossing patterns, there may be provided a background embossing. This background or functional embossing is further suitable to provide the paper product with the required properties as regards the bulk and softness, for example.

Preferably, the height or depth of the first and second protuberances or decorative embossing patterns, respectively, resides within the range of 0.4 to 2.5 mm, preferably within the range of 0.4 to 2.0 mm. The difference in height or depth, respectively, is preferably larger than 0.2 mm, and more preferred, resides within the range of 0.4 to 0.8 mm.

One particularly preferred embodiment of the present invention is the use of colored glue for ply bonding. This leads to the advantage that the glued decorative embossing pattern will be colored, whereas the second embossing pattern, which is not laminated or provided with glue, remains uncolored. This further increases the design variability.

It will be apparent to the skilled person that the first and the second decorative embossing pattern may be varied in a large range. For example, the design elements imparted by the corresponding embossing patterns may be feathers, dolphins, waves, whales, logos, marks, trademarks, which may be provided in different sizes or in combination. In this context, various possibilities are conceivable so that the present invention ought to not be limited to the exact configuration of the design elements as long as at least two design elements having a different height/depth are provided, the multi-ply paper product being laminated at the sites or locations of one of the design elements and being unlaminated at the others .

Further embodiments, advantages and features of the present invention will become apparent from the following description of a preferred embodiment.

Brief Description of the Drawings

The following description of a preferred embodiment of the present invention refers to the appending drawings, in which:

Figure 1 shows a prior art multi-ply paper product in a plan view; Figure 2 schematically shows an apparatus according to one embodiment of the present invention;

Figure 3 is an enlarged view of the contact area between the decoration embossing roll and the glue application roll; and

Figures 4a and 4b show two multi-ply paper products according to the present invention in a plan view, wherein the design elements in the products are different.

Preferred Embodiment of the Present Invention

In Figure 2, there is shown an apparatus for producing a decorative three-ply tissue product. The apparatus shown in Figure 2 comprises a background embossing unit 20 and a ply bonding unit 30. The ply bonding unit 30 comprises a decoration embossing unit consisting of a decoration embossing roll 31 and a counter roll 32. The decoration embossing roll 31 may be a steel roll, whereas the counter roll 32 may be made of rubber. In addition, the ply bonding unit 30 also comprises a glue application unit. The glue application unit comprises a glue application roll 33 and a glue transfer roll 34. The glue transfer roll 34 and the glue application roll 33 are in contact with each other so that glue taken up by the glue transfer roll 34 from a glue bath will be transferred from the glue transfer roll 34 to the glue application roll 33. The decoration embossing roll 31 has embossing protuberances 37 and 38 shown in Figure 3. The first protuberances 37 have a larger height than the second protuberances 38. The height of either one of these protuberances 37 to 38 resides within the range of 0.4 to 2.5 mm. In this context, it is to mention that the height of the protuberances 37 will reside within the range of 0.8 to 2.5 mm, whereas the height of the protuberances 38 will reside within the range of 0.4 to 2.0 mm. The difference in height between the protuberances 37 and 38 should be larger than 0.2 mm and preferably resides within a range of 0.4 to 0.8 mm. In any case, the difference in height should be selected so that substantially no glue is applied to the tops of the second protuberances 38 in the glue application process. Therefore, the glue application roll 33 is arranged in contact with the upper surfaces (tops) of the first protuberances 37 to apply glue to the passing paper web only at these locations . No contact between the upper surfaces (tops) of the second protuberances 38 exists.

Furthermore, the ply bonding unit 30 comprises a marrying roll 35 for combining (bringing together) the plies.

As previously mentioned, the apparatus shown in Figure 2, also comprises a background embossing unit 20. This background embossing unit 20 consists of three embossing roll pairs, a steel embossing roll and a rubber counter roll. The embossing rolls in Figure 2 are referred to by the acronym ST for the steel roll and the counter rolls are referred to by the acronym R for rubber roll. The embossing rollers ST of the background embossing unit also have protuberances (not shown) , which are evenly distributed over the entire peripheral surface of the embossing rolls ST. These protuberances form an embossing pattern which may be referred to as background embossing. The definition of such an embossing pattern may be found above.

In contrast to the embossing pattern imparted by the background embossing unit, the protuberances of the decoration embossing roll 31 of the ply bonding unit 30 are decoration embossing protuberances. I.e., these protuberances 37 and 38 impart a decorative embossing pattern to the ply passed through the embossing unit 30, 32. These embossing patterns may be referred to as decorative embossing patterns a definition of which may also be found above.

In the following, the operation of the apparatus shown in Figures 2 and 3 will be described.

Three plies 40a, 40b and 40c are passed through the background embossing unit. In this context, each ply 40 a-c passes through a nip between a corresponding embossing roll ST and its associated counter roll R. In the nip between the embossing roll and the counter roll, there is imparted a background embossing to each of the plies 40 a-c, which is adapted to obtain the desired properties of the final product. For example, the background embossing may be a so- called "spot embossing" being constituted by a plurality of evenly distributed minute spots. As the provision of a background embossing is known in the art, no further explanation will be provided.

The three plies are then further transported to the downstream ply bonding unit. The ply 40a and the ply 40b are guided via guide rollers to the counter roll 32 and enter the nip between the counter roll 32 and the decoration embossing roll 31. In this nip, a decorative embossing pattern is imparted to these plies, wherein the first protuberances 37 impart a first decorative embossing pattern and the second protuberances 38 impart another second decorative embossing pattern. As the two plies are together passed through the nip a mechanical ply bonding is achieved between these plies . Then the combined plies 40a and 40b, which were pressed in between the protuberances 37 and 38, at the locations of the tops of the protuberances 37 contact the glue application roll 33. The glue used in the glue application unit may preferably be colored glue, such as for example blue glue. The glue is then applied by means of the glue application roll 33 on the ply 40b and only at sites (locations) of the tops of the first protuberances 37. The application of the glue is more clearly visible from Figure 3 in which the passing plies, however, have been omitted for clarity reasons. The transportation direction of the plies, yet, is depicted by the arrows B (which also depict the rotation direction of the glue application roll 33 and the decoration embossing roll 31) .

Then, the two plies 40a and 40b are further transported to a nip between the decoration embossing roll 31 and the marrying roll. The ply 40c is also passed through this nip between the embossing roll 31 and the marrying roll 35. The ply 40c, as a consequence, is bonded to the combined plies 40a and 40b at the glue sites, i.e. the sites (locations) where the glue has been applied to the ply 40b. Therefore, ply bonding is achieved between the ply 40c and the combined plies 40a and 40b.

Subsequently, the combined plies 40a, 40b and 40c leave the ply bonding unit 30, as shown by the arrow A, as finished ply 40. It is to be noted that the term "plies" in regard of the apparatus and method means a web constituted by these plies, i.e. each of the plies is present in the form of a web. In contrast, in the multi-ply paper product, the plies may be separate sheets, which may be connected to each other by means of a perforation, for example. As a consequence, after the combined ply 40 leaves the ply bonding units 30, the web may be cut in two separate sheets or provided with a perforation. This, however, is known by the person skilled in the art so that no detailed explanation of this process and the corresponding apparatus is necessary.

The multi-ply paper product, which may be obtained by the above-described apparatus and method, is depicted in two alternatives in Figures 4a and 4b. The multi-ply paper product shown in Figures 4a and 4b are provided with a background embossing pattern 12, which is imparted by means of the background embossing unit 20. In addition, there is provided a decoration embossing pattern 11a to Hd. In the product shown in Figure 4a, the first decorative embossing pattern Ha has the form of a whale, whereas the second decorative embossing pattern Hb has the form of two waves. The first decorative embossing pattern Ha is imparted by means of the first protuberances 37. Accordingly, the plies are bonded by means of glue (adhesive) only at the locations of the decorative embossing pattern Ha, whereas the plies are unlaminated at the remaining positions, particularly the second decorative embossing pattern Hb. As colored glue, for example blue glue, is used, the whale will have a blue appearance, whereas the waves remain white as the rest of the multi-ply paper product. In the multi-ply paper product as shown in Figure 4b, the first decorative embossing pattern has the form of dolphins and the ply bonding is only achieved at the sites of these design elements forming the first decorative embossing pattern Hc. In addition, there is provided a second decorative embossing pattern Hd in the form of a trademark. This second decorative embossing pattern Hd is imparted by the second protuberances 38 of the embossing roll 31. Accordingly, if again blue glue is used, the dolphins Hc will appear blue, whereas the mark/trademark Hd will have a white appearance as the paper itself. It ought to be noted that in case the color of the paper is different than white, the second decorative embossing pattern will have this color as will the first decorative embossing pattern if no colored glue is used, which, however, is preferred.

It is to be further noted that the above-described embodiment is only one preferred embodiment of the present invention and that various modifications are possible within the scope of the following claims. For example, there may be processed less than thee, i.e. two or more than three plies. In addition, it is also conceivable to provide more than only- two decorative embossing patterns, wherein more than the two embossing protuberances 37, 38 were present. In this case, all of the protuberances should have a different height, wherein the difference between the highest protuberances and the height to the next highest protuberances ought to be larger than 0.2 mm and preferably between 0.4 and 0.8 mm.

Claims

1.- Method for producing a decorative multi-ply paper product, particularly a tissue paper product, comprising the steps of: embossing at least one of the plies by means of an embossing roll having first protuberances to impart a first decorative embossing pattern and second protuberances to impart a second decorative embossing pattern, the first protuberances having a larger height than the second protuberances , applying glue on one side of the at least one ply only at sites corresponding to the tops of the first protuberances, and bringing together the one ply with at least one other ply, whereby ply bonding is achieved at the glue sites.

2. Method as set forth in claim 1, wherein an additional background embossing is imparted to the at least one ply.

3. Method as set forth in claim 1 or 2 , wherein the height of the first and second protuberances resides within the range 0.4 to 2.5 mm.

4. Method as set forth in any one of the preceding claims, wherein the difference in height is larger than 0.2mm and preferably resides within the range of 0.4 to 0.8mm.

5. Method as set forth in any one of the preceding claims, wherein colored glue is applied.

6. Apparatus for producing a decorative multi-ply paper product, particularly a tissue paper product, comprising a decoration embossing unit having a decoration embossing roll having first protuberances to impart a first decorative embossing pattern to at least one ply and second protuberances to impart a second decorative embossing pattern to the at least one ply, the first protuberances having a larger height than the second protuberances; a glue application unit having a glue application roll being in contact with the decoration embossing roll for applying glue on one side of the at least one ply only at sites corresponding to the tops of the first protuberances; and a marrying roll for bringing together the at least one ply with at least one other ply, whereby ply bonding is achieved at the glue sites.

7. Apparatus as set forth in claim 6, further comprising a background embossing unit upstream of the decoration embossing unit and having a background embossing roll having third protuberances .

8. Apparatus as set forth in claim 6 or 7 , wherein the height of the first and second protuberances resides within the range 0.4 to 2.5 mm.

9. Apparatus as set forth in any one claims 6-8, wherein the difference in height is larger than 0.2mm and preferably resides within the range of 0.4 to 0.8mm.

10. Apparatus as set forth in any one of claims 6-9, wherein the glue application unit is adapted to apply colored glue.

11. Multi-ply paper product, particularly made of tissue paper, comprising at least two plies, at least one of the plies having a first decorative embossing pattern and a second decorative embossing pattern, the depth of the first decorative embossing pattern being larger than that of the second decorative embossing pattern, the two plies being bonded at the sites of the first embossing pattern only.

12. Product as set forth in claim 11, further comprising a background embossing pattern.

13. Product as set forth in claim 11 or 12, wherein the depth of the first and second decorative embossing pattern resides within the range 0.4 to 2.5 mm.

14. Product as set forth in any one of claims 11-13, wherein the difference in depth is larger than 0.2mm and preferably resides within the range of 0.4 to 0.8mm.

15. Product as set forth in any one claims 11-14, wherein the first decorative embossing pattern is colored.