TISSUE PRODUCT AND METHOD AND APPARATUS FOR PRODUCING SAME

Abstract

A tissue product with at least four plies made of tissue paper base sheet or nonwoven comprises: a first outer ply and a second outer ply and at least two inner plies between the first outer ply and the second outer ply, wherein only one of the inner plies is un-embossed; the outer plies comprise a micro-embossing pattern; at least one of the outer plies comprises a décor embossing pattern; and at least two adjacent inner plies comprise the un-embossed inner ply and one micro-embossed inner ply; wherein the density of the micro-embossed protrusions of the micro-embossed inner ply is different to the density of further embossed protrusions of the micro-embossing pattern of the outer ply which is adjacent to the micro-embossed inner ply.

Claims

1. A tissue product with at least four plies made of tissue paper base sheet or nonwoven, comprising: a first outer ply and a second outer ply and at least two inner plies between the first outer ply and the second outer ply, wherein only one of the inner plies is un-embossed; at least one of the outer plies comprises a décor embossing pattern; at least two adjacent inner plies comprise the un-embossed inner ply and one micro-embossed inner ply; and the outer plies comprise a micro-embossing pattern, wherein either the density of the micro-embossed protrusions of the micro-embossed inner ply is different to the density of embossed protrusions of the micro-embossing pattern of the outer ply which is adjacent to the micro-embossed inner ply or the micro-embossed protrusions of the micro-embossed inner ply and the embossed protrusions of the adjacent outer ply are not in register with one another.

2. The tissue product according to claim 1, wherein at least one of the embossed plies comprises a double layer or plural layers.

3. The tissue product according to claim 1, wherein a portion of the outwardly facing main surface of the first outer ply is provided with a soft region surrounded by a décor embossing region; the soft region is provided with first micro-embossed protrusions; the décor embossing region comprises first embossed décor protrusions; and the first micro-embossed protrusions are essentially not adhesively bonded to an inner ply adjacent to the first outer ply.

4. The tissue product according to claim 1, wherein the density of the embossed protrusions of the micro-embossing pattern of the inner ply is different to the density of the protrusions of a second micro-embossing pattern of the second outer ply.

5. The tissue product according to claim 3, wherein the first micro-embossed protrusions of the first outer ply, and/or the embossed protrusions of the micro-embossing pattern of the micro-embossed inner ply and/or the protrusions of a second micro-embossing pattern of the second outer ply are arranged in a density from 30 to 200 dots/cm.sup.2.

6. The tissue product according to claim 4, wherein a middle ply adjacent to first outer ply is provided with a décor embossing region with further embossed décor protrusions which are in register with the first embossed décor protrusions.

7. The tissue product according to claim 1, wherein the un-embossed inner ply is adjacent to the first outer ply or second outer ply.

8. The tissue product according to claim 1, wherein at least three inner plies are provided and a first inner ply not adjacent to the first outer ply or second outer ply is provided with a micro-embossing pattern; and a second inner ply between the first inner ply and either the first outer ply or second outer ply is un-embossed.

9. The tissue product according to claim 8, wherein the micro-embossing pattern of the first inner ply extends essentially all over the surface of the first inner ply.

10. The tissue product according to claim 3, wherein less than 0.5% of the first micro-embossed protrusions are adhesively bonded to an inner ply adjacent to the first outer ply.

11. The tissue product according to claim 3, wherein the soft region surrounded by the décor embossing region covers between 25% and 90% of the outwardly facing main surface of the first outer ply.

12. The tissue product according to claim 1, the tissue product either comprising a stack of individual sheets or a roll with transversely extending weakening lines to subdivide the web into individual sheets.

13. The tissue product according to claim 12, wherein the embossing is in register with the dimensions of the individual sheets of the tissue product.

14. The tissue product according to claim 1, wherein the application of glue is restricted to an overall surface fraction of less than 12% of the tissue product.

15. The tissue product according to claim 3, wherein the soft region has an overall oval shape.

16. The tissue product according to claim 1, wherein the décor embossing region of the first outer ply further comprises second embossed décor protrusions with a smaller height than the height of the first embossed décor protrusions.

17. A device for manufacturing a tissue product according to claim 1, comprising: a first engraved roll running against a first anvil roll, wherein the first engraved roll is configured to emboss the first outer ply; a glue application device adjacent to the first engraved roll, and a marrying roll cooperating with the first engraved roll; a second engraved roller running against a second anvil roll, wherein the second engraved roll is configured to emboss the second outer ply; a third engraved roll running against a third anvil roll, wherein the third engraved roll is configured to emboss one of the inner plies; wherein the device further comprises means to direct at least one un-embossed inner ply towards the first engraved roll downstream of the nip between the first engraved roll and the first anvil roll; and there is a gap between the first engraved roll and the second engraved roll, wherein the gap is configured such that the embossed first outer ply and the embossed second outer ply pass through the gap.

18. The device according to claim 17, wherein the first engraved roll has a repeating pattern of embossing protrusions with décor embossing regions surrounding regions provided with micro-embossing protrusions.

19. The device according to claim 17, further comprising an additional embossing roll and an cooperating anvil roll for embossing one of the inner plies.

20. The device according to claim 17, further comprising a perforating device to generate transversely extending weakening lines to subdivide the web into individual sheets.

21. The device according to claim 17, further comprising a stacking device to form stacks of individual sheets of the tissue product.

22. The device according to claim 17, further comprising a winding device to form rolls of the perforated or un-perforated tissue product.

23. A method for manufacturing a tissue product according to claim 17, the method comprising: (a) directing a first outer ply into the nip between a first engraved roll running against a first anvil roll; (b) directing an inner ply into the nip between a third engraved roll running against a third anvil roll to form an embossed inner ply; (c) feeding the embossed inner ply and an un-embossed inner ply towards the first engraved roll downstream of the first anvil roll, wherein either the un-embossed inner ply or the embossed inner ply comes into contact with the embossed first outer ply; (d) directing a second outer ply into the nip between a second engraved roll running against a second anvil roll to form an embossed bottom ply; (e) feeding the embossed second outer ply towards the first engraved roll and into the gap between the first engraved roll and the second engraved roll upstream of the marrying roll; and (f) joining the plies in the nip between the first engraved roll and the marrying roll.

24. The method according to claim 23, wherein an un-embossed ply is brought in direct contact with the embossed first outer ply or second outer ply.

25. The method according to claim 23, further comprising the additional step of directing a second inner ply into the nip between a fourth roll running against a fourth anvil roll.

26. The method according to claim 23, wherein in step (a) either two first outer plies or two second outer plies are embossed together.

27. The method according to claim 23, wherein in step (a) and/or step (d) the outer ply is embossed in two separate steps which is a first pre-embossing step to provide the micro-embossing pattern followed by a second décor embossing step to provide the decor embossing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0097] In the drawings, some embodiments of the invention are shown.

[0098] FIG. 1 schematically shows a cross-sectional view of a first product embodying the invention;

[0099] FIG. 2 schematically shows a top view of a product according to the invention;

[0100] FIG. 3 schematically shows a process for manufacturing a product according to FIG. 1;

[0101] FIG. 4 schematically shows a cross-sectional view of a third product embodying the invention;

[0102] FIG. 5 schematically shows a process for manufacturing a product according to FIG. 6; and

[0103] FIG. 6 schematically shows a process for manufacturing a further alternative product; and

DESCRIPTION OF PREFERRED EMBODIMENTS

[0104] In the following description of exemplary, preferred embodiments, the same reference numerals will be used for the same or similar elements.

[0105] FIG. 1 shows an example of a multi-ply tissue product according to the invention. The tissue product 1 has a first outer ply 4 which is a top ply, and a second outer ply 2 which is a bottom ply. In the following, reference will be made to top ply and bottom ply, respectively, although there is no definition as to which of the outer plies is supposed to be the top ply.

[0106] The top ply 4 and the bottom ply 2 are both provided with an embossing pattern including micro-embossed protrusions 8. However, it is also possible to provide the top ply and/or the bottom ply as so-called structured plies, for example manufactured by means of a Through Air Drying Process.

[0107] In the example according to FIG. 1, two inner plies 17, 18 are provided. The second inner ply 18 adjacent to the bottom ply 2 is un-embossed which means that the second inner ply 18 is not embossed by means of a contact with an embossing roll before it is fed to the final ply-bonding.

[0108] The first inner ply 17 between the second inner ply 18 and the top ply 4 is micro-embossed in order to increase the bulk of the tissue product 1.

[0109] The height h3 of the embossed protrusions 8a of the top ply 4 can be different to the height h1 of the embossed protrusions 8b of the bottom ply 2. Further décor embossed protrusions 9 are provided in the top ply 4. At the décor embossed protrusions 9 with a higher height h2, the ply bonding between the top ply 4 and the second middle ply 17 is generated by means of glue which is applied towards the top surfaces of the décor embossed protrusions. Typical depths of the engraved embossing patterns are between 0.4 mm and 2.0 mm. Since the application of glue is restricted to an overall surface fraction of less than 12%, preferably less than 2.5% of the tissue product, the softness of the product can be increased.

[0110] The application of glue can also be performed on the flat ply.

[0111] Both the top ply 4 and the bottom ply 2 can consist of more than one single layer of tissue web material, for example of a double layer of tissue material.

[0112] As can be seen in FIG. 1, the embossed protrusions 19 of the first middle ply 17 and the embossed protrusions of the adjacent top ply 4 are not in register with one another. This increases the bulk and absorbency of the tissue product 1 because the protrusions 19, 8a cannot nest one into the other which would reduce the thickness of the tissue product.

[0113] Also the provision of different densities of the embossed protrusions 19 of the inner ply 17 and the embossed protrusions 8a of the adjacent outer ply 4 avoid the nesting of the embossed protrusions which increases the bulk and the absorbency of the tissue product.

[0114] In FIG. 2, a top view of a single sheet 20 of the tissue product 1 is shown. The sheet 20 according to FIG. 2 has a soft region 22 with an overall oval shape. Such a shape essentially harmonizes with the rectangular shape of individual sheets so that a relatively large surface area of each sheet can be covered by the soft region. However, the soft region can be circular or rectangular as well. The soft region 22 covers at least 25% and up to 90% of the surface area of the sheet 22.

[0115] Further, a décor embossing region 24 is provided which comprises embossed décor protrusions 26. The embossed décor protrusions can be provided with different shapes, and especially different heights. Besides the embossed décor protrusions 26, second embossed décor protrusions 28 can be provided with a smaller height than the height of the first embossed décor protrusions 26.

[0116] When the embossing is in register with the dimensions of the individual sheets of the tissue product, this has the advantage that each sheet has exactly the same embossing pattern. The soft region can be arranged centered on each individual sheet, and the individual embossing patterns can be arranged such that an undesired nesting of adjacent plies can be prevented.

[0117] The soft region 22 is provided with micro-embossed protrusions 23 which are essentially not adhesively bonded to an inner ply adjacent to the top ply.

[0118] A density of such micro-embossed protrusions 8a (see FIG. 1) above 100 dots/cm.sup.2 and even up to 200 dots/cm.sup.2 has not been feasible for a long time. Only with the option to manufacture embossing rolls using 3D-printing, it has become possible to generate embossing rolls with such a high density of embossing projections on its circumferential surface.

[0119] The claimed technology works for any densities of the embossed protrusions but it is more efficient if the density is high. It has been found that a higher density of the embossed protrusions contributes to the perceived softness of the product. Further, the absorbency performance also increases with the density of the embossed protrusions.

[0120] FIG. 3 schematically shows the device for manufacturing a product according to FIG. 1. The top ply 4, bottom ply 2, first inner ply 17 and the second inner ply 18 are directed into the device 30.

[0121] The central element of the device 30 is the embossing roll S1 which is an engraved steel roll. The top ply 4 which can also be provided as a double layer is directed into the nip between the embossing roll S1 and a counter roll 32 in order to emboss the top ply or top plies 4. After having been embossed, the first middle ply 17 joins the top ply. Before joining the top ply 4 at the embossing roll S1, the first middle ply 17 is micro-embossed in the nip between the engraved steel embossing roll S3 and the counter roll 34.

[0122] After the top ply top plies 4 and the first middle ply 17 have been joined at the embossing roll S1, glue is applied towards the first middle ply 17 by means of a glue application device 36. Since the embossing roll S1 has micro-embossing protrusions of a smaller height and décor embossing protrusions of a higher height, the glue is only applied towards the first middle ply 17 at the décor embossing protrusions with the higher height.

[0123] The second middle ply 18 is un-embossed and fed towards the embossing roll S1 downstream of the glue application device 36. The second middle ply 18 is directed into the gap between the embossing roll S1 and a second embossing roll S2 which also runs against the counter roll 38. The second embossing roll S2 is also an engraved steel roll with a micro-embossing pattern. In the nip between the second embossing roll S2 and the counter roll 38, the bottom ply 2 is embossed. However, the embossing roll 52 can additionally also be provided with décor embossing protrusions. The second middle ply 18 joins first middle ply 17 and the bottom ply 2 and becomes sandwiched between these two.

[0124] After leaving the gap between the embossing roll S1 and the second embossing roll S2, the multi-ply structure is directed into the nip between the embossing roll S1 and a driven marrying roll M1 where the final ply bonding takes place. Downstream of the marrying roll M1, the multi-ply tissue product 1 according to the invention can be directed to a perforating unit 40 at which the tissue product 1 receives perforation lines which are provided at regular intervals in a direction perpendicular to the longitudinal direction of the multi-ply tissue product 1.

[0125] Downstream of the perforating unit 40, the tissue product 1 can either be wound to a roll or folded to become a stack of individual sheets.

[0126] The embodiment according to FIG. 4 is very similar to that according to FIG. 1. As will be appreciated, the position of the inner plies 17 and 18 between the top ply and the bottom ply is reversed to that according to FIG. 1. The corresponding device 30 according to figure distinguishes over that according to FIG. 3 in that the position where the un-embossed middle ply 18 is directed toward the embossing roll S1 is different to that according to FIG. 3. In the device 30 according to FIG. 5, the un-embossed middle ply 18 is directed towards the embossing roll S1 downstream of the nip between the embossing roll S1 and the counter roll 32 in which the top ply 4 is embossed, but upstream before the micro-embossed middle ply 17 is joined. The application of glue at the glue application device 36 is towards the embossed middle ply 17. As in the preceding examples of FIGS. 3 and 5, the bottom ply 2 joins the other plies downstream of the glue application device 36 and runs through the nip between the embossing roll 52 and the counter roll 39, and the gap between the embossing roll S1 and the embossing roll S2. The ply bonding of all plies is carried out like in the devices as discussed above in the nip between the embossing roll S1 and the driven marrying roll M1.

[0127] A further possible process is shown with reference to the device 30 according to FIG. 6. In the device 30 according to FIG. 6, the embossed middle ply 17 consists of two layers which are embossed together in the nip between the embossing roll S3 and the counter roll 34. Between the embossed middle plies 17 and the top ply 4, the un-embossed middle ply 18 is provided. Accordingly, like in the embodiment of FIG. 5, the un-embossed middle ply 18 is directed toward the embossing roll S1 downstream of the nip between the embossing roll S1 and the counter roll 32 in which the top ply 4 is embossed, but upstream of the position at which the micro-embossed middle plies 17 are joined. The application of glue at the glue application device 36 is towards the embossed middle plies 17. As in the preceding examples of FIGS. 3 and 5, the bottom ply 2 joins the other plies downstream of the glue application device 36 and runs through the gap between the embossing roll S1 and the embossing roll S2. The ply bonding is carried out like in the devices as discussed above in the nip between the embossing roll S1 and the driven marrying roll M1.

[0128] All products according to the invention have in common that they have an improved caliper, strength and softness. The advantageous provision of a micro-embossed soft region on the top ply can further make the product both aesthetically pleasing and soft.