EP3802098A1

EP3802098A1 - Method and machine for embossing and calending tissue paper and resulting product

Info

Publication number: EP3802098A1
Application number: EP19735397.2A
Authority: EP
Inventors: Mauro Gelli
Original assignee: Engraving Solutions Srl
Current assignee: VALMET ENGRAVING SOLUTIONS S.R.L.
Priority date: 2018-06-07
Filing date: 2019-06-04
Publication date: 2021-04-14
Also published as: WO2019234603A1; IT201800006097A1; CN112384362A; CN112384362B; BR112020024475A2

Abstract

A method is described for producing a multi-ply cellulose tissue paper web material, comprising at least a first ply (V1) and a second ply (V2) bonded to each other. The first ply (V1) is made to pass between an embossing roller (11) and a first pressure roller (17). The first embossing roller (11) is provided with embossing protuberances (57; 59; 101; 103) distributed according to first annular bands on a lateral surface of the embossing roller (11), between which there are interposed second annular bands without embossing protuberances. The first ply (V1) is embossed along longitudinal embossing bands (53; 102), and calendered along longitudinal calendering bands (51; 104), as a result of the co-action of the embossing roller (11) with the pressure roller (17).

Description

METHOD AND MACHINE FOR EMBOSSING AND CALENDING TISSUE PAPER AND RESULTING PRODUCT

DESCRIPTION

TECHNICAL FILED [0001] Disclosed herein are methods and machines for the production of multi-ply cellulose web material, for example and in particular web material made of tissue paper. Also disclosed are products made of multi-ply tissue paper.

BACKGROUND ART

[0002] An important production sector of paper articles relates to the production of so-called tissue paper, with which single- or multi-ply web materials, typically wound in rolls, are produced. Tissue paper is used for manufacturing toilet paper, paper towels and similar items.

[0003] To achieve several aesthetic and functional features, the tissue paper plies are subjected to embossing processes. This consists in the permanent deformation of the cellulose ply, to create embossing protuberances or protrusions thereon. The em bossing serves to achieve technical and functional features of the finished product, and in some cases also for aesthetic reasons.

[0004] In some cases, embossing is made to create, on the cellulose ply, limited ar eas of application of an adhesive, which serves to bond together two or more plies that constitute the finished multi-ply product. By embossing one or more plies, em bossed protrusions facing towards an opposite ply, i.e. towards the inside of the mul ti-ply material, are generated on the ply. The adhesive is applied to the head surface of the embossed protrusions.

[0005] In some cases, the embossing must therefore be configured so as to obtain an optimal adhesive distribution, to ensure correct bonding of the plies of a multi-ply web material, obtaining at the same time a soft product, therefore not excessively glued, and avoiding an excessive consumption of adhesive, which in any case consti tutes a consumable material that affects the total cost of the finished product. [0006] In some cases, embossing also has the purpose of increasing the overall thickness of the web material and/or of imparting certain features of resistance to crushing.

[0007] In some products, embossing has aesthetic and technical/functional purpos- es. The embossing pattern cannot be chosen as desired exclusively as a function of aesthetic needs, since it also performs technical functions and must respect certain constraints and limits.

[0008] In general, one or more plies of a multi-ply cellulose web material of tissue paper are also embossed in order to impart the desired features of softness and liquid absorption capacity, depending on the final use of the cellulose product.

[0009] There is therefore a continuous search for technical solutions that allow im proving the technical-functional aspects of the cellulose product, while imparting an aesthetically pleasing appearance thereto, as well as being pleasant to the touch, to promote and favor the penetration thereof on the market. SUMMARY

[0010] According to a first aspect, a method is provided for producing a multi-ply cellulose tissue paper web material, comprising at least a first ply and a second ply bonded to each other, wherein the first ply is fed between an embossing roller and a first pressure roller, wherein the embossing roller is provided with embossing protu- berances distributed according to first annular bands on a lateral surface of the em bossing roller, between which second annular bands without embossing protuberanc es are interposed. The first ply is embossed along longitudinal embossing bands by the embossing protuberances arranged along the first annular bands as a result of co action of the embossing roller with the pressure roller. Moreover, the ply is simulta- neously calendered along longitudinal calendering bands along the second annular bands, as a result of the co-action of the embossing roller with the pressure roller.

[0011] As will be shown below, calendering allows obtaining particular benefits in terms of softness of the cellulose material. Embossing may have technical and/or aes thetic functions, and may for example be useful for masking mechanical ply bonding areas between the plies, as described in greater detail below. [0012] In some embodiments, the pressure roller may have a rigid surface, provided with recesses or protuberances which mesh with protuberances of the embossing roller, and smooth annular bands which co-act with the second annular bands of the embossing roller. [0013] However, in preferred embodiments the pressure roller has a yieldable coat- ing, for example and preferably made of elastic material. In this case, the method may provide for the protuberances of the first embossing roller to be pressed against a yielding coating of the first pressure roller, so that the first ply is embossed as a re- sult of the penetration of the embossing protuberances of the first embossing roller into the yielding coating of the first pressure roller. Furthermore, the first ply is cal- endered along the longitudinal calendering bands by co-action of the first embossing roller with the surface of the yielding coating of the first pressure roller.

[0014] The plies may be bonded together by gluing, for example by performing a further embossing step of the first ply along the calendered longitudinal bands, in or- der to define areas for glue application.

[0015] In other embodiments, the plies may be bonded together by mechanical ply- bonding. As known to those skilled in the art, and as used herein, the term "mechani cal ply-bonding" defines a technique for bonding cellulose layers based on the appli cation of a strong pressure on the plies, so as to generate bonding or welding points between the cellulose fibers that form them.

[0016] According to another aspect, an embossing machine is provided, compris ing:

- a first embossing roller provided with embossing protuberances distributed according to first annular bands on a lateral surface of the embossing roller, between which second annular bands without embossing protuberances are interposed;

- a first pressure roller co-acting with the first embossing roller for embossing and calendering a first ply of web material;

- a first path for the first ply extending through a first embossing nip, between the first embossing roller and the first pressure roller.

[0017] According to a still further aspect, a multi-ply cellulose web material is pro- vided, comprising at least a first ply and a second ply bonded to each other, wherein the first ply comprises longitudinal calendering bands interposed between longitudi- nal embossing bands. The web material may be wound in rolls, preferably in rolls formed by sheets connected to one another by perforation lines, for example rolls of toilet paper, kitchen paper or other tissue paper products.

[0018] Further advantageous features and embodiments of the method, of the web material and of the machine object of the present disclosure are described hereafter with reference to exemplary drawings, and in the appended claims, which form an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention will be better understood by following the description and the accompanying drawings, which illustrate an exemplifying and non-limiting embodi- ment of the invention. More particularly, in the drawings:

Fig. 1, a diagram of an embossing machine in a first embodiment;

Fig. 2, a view of a portion of the lateral cylindrical surface of the first em bossing roller of the machine in Fig. 1;

Fig. 3, an enlargement of a portion of Fig. 9;

Figs. 4 and 5, enlarged sections along lines IV-IV and VV of Fig. 3;

Fig. 6, a view of a portion of the lateral cylindrical surface of the second embossing roller of the machine in Fig. 1;

Fig. 7, an enlargement of a portion of Fig. 6;

Fig. 8, an enlarged section according to the line VIII- VIII of Fig. 7;

Fig. 9, a view of a portion of the lateral cylindrical surface of the third em bossing roller of the machine in Fig. 1;

Fig. 10, an enlargement of a portion of Fig. 9;

Figs. 11 and 12, enlarged sections along lines XI-XI and XII-XII of Fig. 10; Fig. 13, a schematic section of a web product obtainable with the machine in Figs. 1 to 12;

Fig. 14, a diagram of an embossing machine in a further embodiment;

Fig. 15, a view of a portion of the lateral cylindrical surface of the first em bossing roller of the machine in Fig. 14;

Figs. 16 and 17, enlarged sections along lines XVI-XVI and XVII-XVII of Fig. 15;

Fig. 18, a lateral view of a portion of the lateral cylindrical surface of the second embossing roller of the machine in Fig. 14;

Fig. 19, an enlarged section according to the line XIX-XIX of Fig. 18;

Fig. 20, a view of a portion of the lateral cylindrical surface of the third em bossing roller of the machine in Fig. 14;

Figs. 21 and 22, enlarged sections according to lines XXI-XXI and XXII- XXII of Fig. 20;

Fig. 23, a schematic section of a web product obtainable with the machine in Figs. 14 to 22;

Figs. 24, 25 and 26, schematic lateral views of further embodiments of an embossing machine;

Fig. 27, a web material N wrapped in a roll, obtainable with a machine as described herein; and

Figs. 28 to 31, summary flowcharts of methods of producing rolls of web material according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] Embossing machines for processing plies for the production of a multi-ply web material are described below. The embossing machine has an embossing roller which has annular bands on which embossing protuberances are provided, which are spaced apart from each other by annular zones, without embossing protuberances, which perform a calendering operation on the ply. In this way, a particularly soft cel lulose ply is obtained, which can then be subsequently processed to be bonded to one or more cellulose plies of various configurations, by means of gluing, mechanical ply-bonding, or other technique of reciprocal bonding of the plies.

[0021] Turning now to the illustrated embodiments, Fig. 1 schematically shows a first embodiment of an embossing machine 1 for the production of an embossed web material made of tissue paper. The machine 1 may comprise a first embossing unit 3 and a second embossing unit 5.

[0022] In the embodiment in Fig. 1, the first embossing unit 3 comprises a first em bossing roller 11, which may be provided with embossing protuberances defining an embossing pattern indicated as a whole with reference numeral 13. The first emboss- ing roller 11 is adapted to rotate around a respective rotation axis 11A in the direc- tion indicated by the arrow fl 1. The first embossing roller 11 can be driven in rota- tion by a respective motor, not shown. [0023] A distributor 15 to distribute a liquid substance can be associated to the first embossing roller 11 . The distributor can be adapted to distribute a water-based liq uid. For example, the distributor 15 can be adapted to distribute an ink. As used here in, the term“ink” indicates any liquid substance, preferably water-based, containing a pigment. Preferably, the distributor 15 distributes a liquid lacking glue. [0024] With the first embossing roller 11 co-acts a first pressure roller 17, adapted to rotate according to the arrow fl7 around a respective rotation axis 17A. The first pressure roller 17 can be provided with a lateral surface coated with a coating 17R, preferably made of elastically yielding material. The coating 17R can be made for example of rubber, synthetic rubber, or other suitable elastomeric material. The first embossing roller 11 and the first pressure roller 17 define a first embossing nip 21, through which passes a first path for a ply VI of web material, for example a ply of tissue paper. The ply VI can consist of a single layer or of a plurality of layers or plies of cellulose material. For example, the first ply VI can have grammage between 10 g/m² and 50 g/m², preferably between 12 g/m² and 30 g/m². [0025] The first pressure roller 17 and the first embossing roller 11 are pressed against each other so that the embossing protuberances 13 penetrate in the elastically yielding coating 17R of the pressure roller 17 imparting a permanent deformation to the ply VI of tissue paper that passes through the first embossing nip 21. The distrib utor 15 is adapted to apply the liquid substance on at least some embossed protru- sions formed on the ply VI by the embossing protuberances 13 of the embossing roller 11.

[0026] In the embodiment of Fig. 1, the second embossing unit 5 comprises a sec ond embossing roller 23, provided with embossing protuberances, which define an embossing pattern 25, and adapted to rotate around a rotation axis 23A according to arrow f23. The second embossing roller 23 can be driven in rotation by a motor, not shown. To the second embossing roller 23 is associated a distributor 26 of a liquid substance, for example adapted to apply a glue on embossed protrusions generated by the second embossing roller 23 on the first ply of tissue paper VI, as described below.

[0027] The second embossing roller 23 co-acts with a second pressure roller 27, adapted to rotate around a respective rotation axis 27A according to arrow f27. The second pressure roller 27 can be provided with a coating 27R made of an elastically yielding material, similar to the coating 17R of the first pressure roller 17. The sec- ond embossing roller 23 and the second pressure roller 27 form a second embossing nip 29 therebetween, through which the path of the first ply VI extends. In the sec- ond embossing nip, the first ply VI can be subjected to a second embossing opera- tion, i.e. mechanical deformation, by effect of the penetration of the embossing pro- tuberances 25 of the second embossing roller 23 in the elastically yielding coating 27R of the second pressure roller 27, which is pressed against the second embossing roller 23. [0028] In the embodiment shown in Fig. 1, the second embossing unit 5 comprises a third embossing roller 31, adapted to rotate according to arrow f3 l around a rota- tion axis3 lA, by means of a motor, not shown. The third embossing roller 31 is pro- vided with embossing protuberances defining an embossing pattern indicated as a whole with reference numeral 33. The third embossing roller 31 co-acts with a third pressure roller 35, adapted to rotate around a respective rotation axis35A according to arrow 35 The third pressure roller 35 can be provided with an elastically yielding coating 35R, similar to the coating 17R of the first pressure roller 17 and to the elas- tically yielding coating 27R of the second pressure roller 27. Between the third em bossing roller 31 and the third pressure roller 35 an embossing nip 37 is defined, whereat the embossing protuberances 33 of the third embossing roller 31 press against the elastically yielding coating 35R of the third pressure roller 35 and pene- trate in said coating 35R, so as to emboss a second ply of tissue paper V2, which is fed along a respective feed path. The second ply of tissue paper V2 can have an overall grammage between 10 g/m² and 50 g/m², preferably between 12 g/m² and 30 g/m². The ply V2 can be single or multiple, i.e. it can in turn be made up of two or more layers or plies.

[0029] The path of the second ply of tissue paper V2 extends around the third pres- sure roller 35 and around the third embossing roller 31 and from there towards the second embossing roller 23. After being embossed between the third embossing roll- er 31 and the third pressure roller 35, the second ply V2 detaches from the third em bossing roller 31 and follows the path towards the second embossing roller 23. The path of the ply VI and the path of the ply V2 join in a laminating nip 38, defined be- tween the second embossing roller 23 and a laminating roller 39, adapted to rotate around a respective rotation axis39A according to arrow f39. The laminating roller 39 can be coated with an elastically yielding material, for example an elastomer, a natural or synthetic rubber, preferably having greater hardness than the hardness of the coating 17R of the first pressure roller 17 and of the coating 27R of the second pressure roller 27. In other embodiments, the laminating roller 39 can have a rigid cylindrical surface. The term“rigid” means, in this context, a surface that does not undergo detectable compression deformations at the pressure that is generated be- tween the embossing protuberances 25 of the second embossing roller 23 and the laminating roller 39.

[0030] In some embodiments, the laminating roller 39 is mounted idle and driven in rotation by pressure with the embossing roller. In other embodiments, the laminating roller 39 can be motorized.

[0031] In the laminating nip 38, the second ply V2 is pressed against the first ply VI to cause the mutual gluing of the plies, as described in more detail below.

[0032] Figs. 2 to 12 described below illustrate possible embodiments of the em bossing protuberances of the first and second embossing rollers 11 and 23 and of the respective embossing protuberances generally indicated with reference numeral 13 and 25 in Fig. 1. Fig. 13 schematically shows a product obtainable with the emboss ing rollers and respective protuberances shown in Figs. 2 to 12.

[0033] More particularly, Fig. 2 shows a plan view of a portion of the lateral sur face of the first embossing roller 11. In this embodiment, the first embossing roller 11 comprises an embossing pattern with annular bands. In some embodiments, the cylindrical lateral surface of the first embossing roller 11 comprises annular bands 51 of greater width, spaced apart from one another and separated by annular bands 53 of smaller width, where width means the dimension of the annular band in the axial di- rection, i.e. parallel to the rotation axis of the first embossing roller 11.

[0034] The annular bands 53 may have an embossing pattern of shape substantially different from the annular bands 51. In some embodiments, the width of the annular bands 51 is equal to or greater than three times, preferably equal to or greater than four times, the width of the annular bands 53.

[0035] In some embodiments, in each annular band 51 the embossing roller 11 has a smooth surface, free of embossing protuberances. The substantially cylindrical sur face is indicated with reference numeral 55.

[0036] In the annular bands 53, an embossing pattern is arranged which can be formed by the combination of one or more different series of embossing protuber ances.

[0037] In the embodiment shown in Figs. 2 to 4, the embossing pattern of the annu lar bands 53 comprises a first series of embossing protuberances 57 and a second se ries of embossing protuberances 59. Preferably, the embossing protuberances 57 of the first series are discrete protuberances, i.e. discontinuous and separate from each other. In the embodiment of Figs. 3 and 4, the embossing protuberances 57 of the first series of embossing protuberances have a truncated-pyramidal shape with an ap proximately square or rectangular base, but the possibility of using different shapes, for example truncated cones with a circular or elliptical cross section or truncated pyramids with a triangular, pentagonal, hexagonal base, etc., is not excluded. In Fig. 4, H57 indicates the height of the protuberances 57.

[0038] In some embodiments, the embossing protuberances 59 can be linear protu berances, i.e. with a longitudinal dimension much greater than the width thereof, in a plan view, i.e. in a view according to Fig. 2. For example, in some embodiments the embossing protuberances 59 can define a continuous pattern, meaning that each pro tuberance extends throughout the entire development of the cylindrical surface of the embossing roller 11. In the embodiment of Fig. 2, for example, in each annular band 53 the embossing protuberances 59 have a continuous fretted pattern, and define a sequence of squares aligned according to the diagonal thereof, extending over the en- tire circular development of the respective annular band 53. The embossing protu berances 57 are distributed inside and outside the squares defined by the embossing protuberances 59.

[0039] In some embodiments, as shown in the section in Fig. 4, the protuberances 59 have a height H59 greater than the height H57 of the protuberances 57.

[0040] In some embodiments, the head surface of the protuberances 59 may be flat, i.e. smooth. In other currently preferred embodiments, as shown in Figs. 2 and 4, each embossing protuberance 59 has a body 59.1 terminating with a front or head surface, from which small embossing tips 59.2 extend. For example, the size of the tips 59.2 can be such that on the width of each protuberance 59 more tips 59.2 can be arranged, for example three tips 59.2 aligned in the direction of the width of the pro- tuberances 59, as shown by way of example in Fig.4.

[0041] In some embodiments, the body 59.1 of the protuberances 59 has a height H57, and the difference between heights H59 and H57 is given by the height of the tips 59.2.

[0042] In some embodiments, the difference between the height H59 and the height H57 can be between about 0.1 and about 0.5 mm, preferably between about 0.2 and about 0.4 mm.

[0043] Fig. 5 shows a section along the line V-V in Fig. 2, in which a portion of the cylindrical surface 55 and the adjacent protuberances 57 are visible. As can be seen in Fig. 5, the cylindrical surface 55 is lowered, i.e. it has a smaller diameter, with re- spect to the embossing protuberances 57, for the purposes to be clarified below.

[0044] Fig. 2 shows two dashed and dotted lines T. These lines represent the posi- tion in which the web material obtained from the embossing machine 1 is cut to pro- duce single finished rolls, as will be described below. In substance, the annular bands 53 are positioned, with respect to the final web material, so that the embossing made by them is located near, but not superimposed on, the longitudinal edge of the web material wound in roll. More details on this aspect will be explained below.

[0045] Figures 6, 7 and 8 show a plan view of a portion of the cylindrical surface of the second embossing roller 23 and a possible embodiment of the embossing pattern 25. In the illustrated embodiment, the embossing protuberances which define the embossing pattern 25 consist of a series of embossing protuberances 61. [0046] The embossing protuberances 61 can be protuberances of simple geometric shape, dot-shaped, for example having a truncated pyramidal or truncated-conical shape, as shown in the illustrated example. H61 (Fig. 8) indicates the height of the protuberances 61. Preferably, the height H61 of the protuberances 61 is equal to or slightly greater than the height of the protuberances of the embossing pattern 13 of the first embossing roller 11, i.e. H61 is equal to or greater than H59. In some em bodiments, the height H61 is from about 0.1 to about 0.5 mm greater than H59. Pref erably, the height H61 is from about 0.2 to about 0.4 mm greater than H59.

[0047] The protuberances 61 are preferably distributed according to annular bands, as shown in Fig. 6. More particularly, on the embossing roller 23 annular bands 63 are provided, in which an embossing pattern is provided, generally indicated with 25 in Fig. 1, consisting of protuberances 61, interspersed with bands 65, without protu- berances 61. The annular bands 63 are in phase with the annular bands 51 of the first embossing roller 11, in such a way that the embossing protuberances 61 make an embossing of the ply VI in longitudinal bands interposed between longitudinal bands decorated with embossing made by protuberances 57 and 59. The bands 65 of the embossing roller 23 preferably have a smooth cylindrical surface 62.

[0048] Since the height H61 of the embossing protuberances 61 of the embossing roller 23 is greater than the height H57, H59 of the embossing protuberances of the embossing roller 11, the glue distributor 26 will apply glue only on the surface of the ply VI, which is on the embossing protuberances 61, in the annular bands 63.

[0049] In some embodiments, the embossing protuberances 61 can be distributed with a density comprised, for example, between about 10 about 100 protuberanc- es/cm², preferably between about 15 and about 80 protuberances/cm² and even more preferably between about 20 and about 60 protuberances/cm².

[0050] Figs. 9 to 12 show an embodiment of the embossing protuberances forming the embossing pattern 33 of the third embossing roller 31. In some embodiments, the embossing roller 31 has an embossing pattern divided into annular bands, similarly to the embossing pattern 13 and to the embossing pattern 25 of the first embossing roll- er 11 and of the second embossing roller 23. In Fig. 9, reference numeral 71 indicates first annular bands interspersed with second annular bands 73. The annular bands 71 and 73 are in phase with the annular bands 51 and 53, respectively, of the first em bossing roller 11, and with the annular bands 63, 65, respectively, of the second em bossing roller 23.

[0051] In some embodiments, in the annular bands 71 there is provided a respective series of embossing protuberances 75, having a height H75 (Fig. 11). The height H75 can be approximately equal to the height H61 of the protuberances 61 (Fig. 8).

[0052] The embossing protuberances 75 are preferably dot-shaped, for example with a truncated pyramidal or truncated cone shape and of small dimensions. In some embodiments, the head surfaces 75.1 may have a circular shape with a diameter comprised, for example, between about 0.1 and about 2 mm, preferably between about 0.5 mm and about 1.5 mm, for example equal to about 0.9-1.1 mm.

[0053] In some embodiments, the head surface 75.1 of the protuberances 75 can be between about 0.5 mm² and 2 mm².

[0054] In some embodiments, the embossing protuberances 75 can be distributed with a density comprised, for example, between about 10 about 100 protuberanc es/cm², preferably between about 15 and about 80 protuberances/cm² and even more preferably between about 20 and about 60 protuberances/cm².

[0055] A series of embossing protuberances 77 is arranged in the annular bands 73. The protuberances 77 (Figs 10 and 12) can have a height H77, preferably less than the height H75 of the protuberances 75. In some embodiments, the height H77 can be equal to the height H57 of the protuberances 57 arranged in the annular bands 53 of the embossing roller 11.

[0056] In some embodiments, the size of the head surface 77.1 of at least some, and preferably of most of the protuberances 77 is greater than the head surface 75.1 of the protuberances 75. For example, the head surface of the embossing protuberances 77 can be between about 2 mm² and about 9 mm², preferably between about 3 mm² and about 5 mm².

[0057] Due to the size of the protuberances of the various embossing rollers 11, 23, 31, and in particular of the heights of these protuberances, the distributor 15 applies a colored liquid on the ply VI at the head surfaces of only the tips 59.2 which have an overall height H59 greater than the protuberances 57 and the body 59.1 of the protu- berances 59.

[0058] Likewise, the glue distributor 26 applies the glue C on the ply VI at the pro- tuberances 61. In the laminating nip 38, the protuberances 61 are pressed against the laminating roller 39 causing mutual bonding of the plies VI and V2 due to the glue applied to the ply VI at the protuberances 61.

[0059] Fig. 13 schematically shows a section of a portion of web material N, which is obtained at the outlet of the laminating nip 38. The section is taken in a transition zone between the two longitudinal bands of the web material N which correspond to the annular bands 53, 65, 73 and respectively 51, 63, 71.

[0060] The embossed protrusions obtained with the embossing protuberances de- scribed above are indicated on the plies VI and V2. Each embossed protrusion is in dicated with the letter "P" followed by a reference which corresponds to the refer ence numeral indicating the corresponding embossing protuberance of the embossing roller that generated it. Therefore, on the ply VI in the longitudinal band 51/63/71 which was processed by the corresponding annular bands 51, 63 and 71 of the em bossing rollers 11, 23, 31 there are embossed protrusions P57 and P59.1/P59.2 formed by the embossing protuberances 57 and 59.1/59.2 of the embossing roller 11. The head surfaces of the embossed protrusions P59.2 can be decorated with a colored liquid L applied by the distributor 15. Furthermore, again in the longitudinal band 51/63/71 of the ply VI there are embossed protrusions P61, formed by the embossing protuberances 61 of the embossing roller 23. These embossed protrusions P61 are provided with adhesive C through which the ply VI is bonded to the ply V2.

[0061] In the longitudinal band 51/63/71, on the ply V2 there are embossed protru- sions P75, formed by the embossing protuberances 75 of the embossing roller 31. The embossed protrusions P75 nest randomly between the embossed protrusions P61. The head surfaces of the embossed protrusions P61 are glued by the adhesive C in the spaces between the embossed protrusions P75. In the longitudinal bands 53/65/73, the ply V2 has embossed protrusions P77, formed by the embossing protu- berances 77 of the embossing roller 31.

[0062] The embossing patterns described for the embossing rollers 11, 23, 31 have a phase in the axial direction (i.e. in the direction of the rotation axis of the emboss- ing rollers), meaning that the annular bands 51, 63 and 71 are aligned with each other so as to process the same longitudinal bands of the plies VI, V2. Likewise, the annu- lar bands 53, 65 and 73 are consequently aligned in axial direction and aligned to process the corresponding longitudinal bands of the plies VI, V2. Vice versa, the embossing patterns of the various rollers do not need to be in phase in the tangential direction, i.e. it is not necessary to have a correspondence in the machine direction (feed direction of the plies VI, V2) of the embossing patterns of the various emboss- ing rollers. [0063] The result obtained on the web material N from the embossing patterns de- scribed so far with reference to Figs. 1 to 13 is the following. In the longitudinal bands 53; 65; 73 of the web material N, a decoration is obtained from the combina- tion of embossed protrusions P59.1, P59.2 and P57. The head surfaces of the em bossed protrusions P59.2 can be decorated with a colored liquid or ink. The decora- tion can be formed by very small points, the size of the head surfaces of the tips 59.2. The embossed protrusions P77 generated on the ply V2 by the protuberances 77 of the third embossing roller 31 are in phase with the embossed protrusions P59.1, P59.2, P57 and can provide a support against crushing of the decorative embossed protrusions P59.1, P59.2. P57, so that the decoration is not damaged when the web material N is wrapped to form a roll.

[0064] The glue C which bonds the two plies VI, V2 is applied according to spots in the bands 51; 63; 71. At the band 51, the ply VI was calendered between the em bossing roller 11 and the pressure roller 17. In fact, in the annular bands 51 the em bossing roller 11 is smooth and has a smaller diameter than the diameter of the cylin- drical surface on which the head surfaces of the protuberances 57 and of the tips 59.2 lie. Consequently, when the pressure roller and the embossing roller 11 are pressed against each other at the embossing nip 21, in the areas corresponding to the annular bands 53 the protuberances 57, 59 penetrate the elastically yielding coating 17R of the pressure roller, causing the embossing, i.e. the permanent deformation of the ply VI, while at the annular bands 51 the ply VI is calendered as a result of the pressure between smooth and opposite cylindrical surfaces of the embossing roller 11 and the pressure roller 17. [0065] The longitudinal bands of the ply VI thus calendered are then embossed by the protuberances 61 of the embossing roller 23.

[0066] Therefore, the longitudinal bands 51/63/71 of the web material N are "longi tudinal calendering bands", meaning that along said bands at least one ply (VI) has been calendered before being possibly embossed. The calendering operation is per formed on the single or multiple ply, which will constitute the outer ply of the fin ished product. In the embodiments described below, the possibility is also provided that the calendered bands of the ply VI are not subsequently embossed. The longitu dinal bands of calendering are interposed between "longitudinal embossing bands" 53; 65; 73, so called since the large embossing with a predominantly decorative ef fect, generated by the first embossing roller 11, are made along them.

[0067] Overall, the longitudinal calendered bands of the ply VI are smoother and softer to the touch, attenuating the hardening and stiffening effect caused by the ap plication of adhesive. In this way, an effective bonding of the plies VI, V2 and a product of high softness is obtained.

[0068] In different embodiments, not shown, between the first ply VI and the sec ond ply V2, a third ply may be inserted, which may be smooth or embossed. For ex ample, the third ply can be guided around the roller 49 (Fig. 1).

[0069] Fig. 14 schematically shows a further embodiment of an embossing ma- chine, indicated as a whole with reference numeral 100, for the production of an em bossed multi -ply web material N made of tissue paper. The machine 100 comprises elements and components corresponding to those of the machine 1 in Fig. 1, which are marked with the same reference numerals and which will not be described again.

[0070] The main difference between the machine 100 and the machine 1 consists in that the third embossing roller 31 of the second embossing unit 5 is placed adjacent to the second embossing roller 23. In this way it is possible, for example, to maintain the phase between the embossing roller 31 and the embossing roller 23 to couple the plies VI and V2 in a tip-to-tip arrangement, rather than nested, as shown in Fig. 13. As is known to those skilled in the art, in a tip-to-tip arrangement the embossing pro- tuberances of the roller 31 are at least in part at the embossing protuberances of the roller 23 and correspondingly the embossed protrusions formed on the plies VI, V2 by the embossing rollers 23, 31 will be found in tip-to-tip position. In the nip formed between the embossing rollers 23 and 31, the embossing protuberances 25 of the em bossing roller 23 and the embossing protuberances 33 of the embossing roller 31 can be pressed against each other, so as to press the plies VI and V2 together and cause lamination and bonding thereof. It is therefore possible to eliminate the laminating roller 39.

[0071] Figs. 15 to 22 show details of the embossing patterns 13, 25, 33 of the em bossing rollers 11, 23, 31. Similar to what has been described with reference to Figs. 2 to 12, also in the embodiment of Figs. 15 to 22 the embossing patterns comprise annular bands with different distributions and shapes of the embossing protuberanc es. The annular bands of the embossing patterns of the various embossing rollers are aligned with one another, i.e. in phase. In practice, the various annular bands of the different embossing rollers are aligned with each other in the transverse direction, parallel to the axes of rotation of the embossing rollers. [0072] Figs. 15 to 17 show details of the embossing pattern 13 of the embossing roller 11. In some embodiments, annular bands are provided on the embossing roller 11 which are spaced apart in the direction of the rotation axis 11 A and indicated with reference numeral 102. Embossing protuberances 101 and 103 are distributed in the annular bands 102. [0073] Between two successive embossing bands 102 there is provided a band 104 without embossing protuberances, in which the embossing roller 11 has a smooth cy lindrical surface 120.

[0074] In the illustrated embodiment, different annular bands 102 contain emboss ing protuberances 101 and 103 of different shapes. Figs. 16 and 17 illustrate exem- plary and non-limiting embodiments of embossing protuberances 101 and 103, re spectively.

[0075] The embossing protuberances 101 and 103 can have heights H101 and H103. In the example shown, the heights H101 and H103 are equal to each other. In general, the protuberances 101 and 103 define decorative patterns. The embossing protuberances can have continuous head surfaces, as shown for the embossing protu berance 101 in Fig. 16, or discontinuous head surfaces, as shown for the embossing protuberance in Fig. 17. In practice, the embossing protuberances 103 have a body 103.1 with a head surface 103.2, from which tips 103.3 extend, which define discon tinuous front surfaces, i.e. point-like surfaces.

[0076] On the areas of the ply VI embossed by the protuberances 101, 103, the dis- tributor 15 can apply a colored liquid. The shape of the protuberances 103 is such that the coloring of the ply VI at these protuberances is discontinuous, that is, point like or pixel-like, instead of a full color. Fig. 15 shows two strips or bands with pro tuberances 101 and two strips or bands 102 with protuberances 103. This is by way of example only, it being understood that the distribution of the full and pixelated front surface protuberances can be different. For example, only protuberances 101 with a full front surface, or only protuberances 103 with a pixel -like surface can be provided. Or the protuberances 101 and 103 can both be present in all the bands 102, with alternate arrangements in any desired sequence. In general, although in the illus trated embodiment each band 102 comprises protuberances 101 or 103 all equal to each other, this is not necessary. For example, decorative protuberances of different shapes may be seen in each band 102.

[0077] The height H101 and H103 of the protuberances 101 and 103 can be for ex ample between about 0.1 mm and about 1 mm, preferably between about 0.5 mm and about 0.9 mm, for example around about 0.6- 0.8 mm. [0078] In general, the height of the protuberances 101 and 103 is sufficiently lim ited to almost completely penetrate the elastically yielding coating 17R of the pres sure roller 17. In this way, in the bands 104 without embossing protuberances the ply VI is calendered between the smooth cylindrical surface 120 of the embossing roller 11 and the smooth cylindrical surface of the coating 17R of the pressure roller 17. Calendering contributes to obtaining a particularly smooth cellulose material, as de scribed above. This is particularly appreciated when the user perceives it on the ex ternal side of the product.

[0079] The embossing roller 23 can have an embossing pattern 25 consisting of protuberances of simple geometric non-decorative shape, for example truncated cone or truncated pyramidal, therefore substantially dot-shaped. Preferably, the embossing roller 23 has annular bands provided with micro-embossing protuberances, indicated with reference numeral 105 in Figs. 18 and 19. Fig.19 is an enlarged section along the line XIX-XIX of Fig. 18.

[0080] As shown in Fig. 18, the protuberances 105 are distributed in annular bands 106, spaced apart from each other by annular bands 108 without embossing protu- berances. The annular bands 106 are aligned in the machine direction, that is, in the direction of advancement of the ply VI, with the annular bands 104, while the annu- lar bands 108 without protuberances 105 are aligned in the machine direction with the annular bands 102. In this way, the protuberances 105 emboss the ply VI in the bands that have been previously calendered between the embossing roller 11 and the pressure roller 17, while the longitudinal bands embossed by the embossing protu- berances 101, 103 remain intact and do not undergo any embossing process in the embossing nip 29.

[0081] In some embodiments, the embossing protuberances 105 may have an ap- proximately truncated conical or truncated pyramidal shape. The protuberances 105 can have a height H105, preferably greater than the height H101 and the height H103 of the protuberances 101 and 103 of the embossing roller 11. In this way, the crush ing of the decorations obtained on the ply VI by means of the embossing roller 11 is avoided. For example, the protuberances 105 may have a height from about 0.5 mm to about 2 mm greater than the heights H101 and H103, preferably from about 0.7 mm to about 1.3 mm and more preferably about 1 mm greater than the height H101 and at height H103.

[0082] The protuberances 105 may have a density between about 10 and about 80, preferably between about 30 and about 60 protuberances/cm² in the bands 106.

[0083] The glue distributor 26 is arranged to apply glue on the deformed and em bossed portions of ply VI from the embossing protuberances 105.

[0084] The third embossing roller 31 can have a pattern of embossing protuberanc es 33 configured as shown in Figs. 20 to 22. Also, in this case the embossing pattern 33 is according to annular bands. In annular bands 112 there are embossing protuber ances 107 of greater dimensions than the embossing protuberances 109 arranged in side annular bands 114. The annular bands 114 are aligned with the annular bands 104 of the embossing roller 11 and with the annular bands 106 of the embossing roll- er 23. The annular bands 112 are, on the other hand, aligned with the annular bands 102 of the embossing roller 11 and with the annular bands 108 of the embossing roll- er 23.

[0085] In some embodiments, the protuberances 107 arranged in the annular bands 112 have a large-sized head surface, i.e. for example, with an area ranging from about 20 to about 100 mm². They can be of simple geometric shape, for example truncated cone or truncated-pyramidal as shown in the figure. The base of the trun cated-pyramidal pyramids may be hexagonal, as illustrated by way of example, or of another polygonal shape, for example square, rectangular, triangular, pentagonal, oc- tagonal, etc.

[0086] Advantageously, the head surface and the pitch between the protuberances 107 is such that the ply V2 embossed by these protuberances 107 forms embossed protrusions, facing towards the inside of the resulting web material N, which form a support for the embossed protrusions obtained from the protuberances 101, 103, without the need for a phasing, that is, of a synchronization in the tangential direc- tion, i.e. in the machine direction, of the embossing rollers.

[0087] The protuberances 107 may have a small height H107, so as not to increase the thickness of the ply V2 excessively. For example, the height H107 can be be- tween about 0.1 and about 1 mm, preferably between about 0.2 and 0.7 mm, even more preferably between about 0.3 and 0.5 mm.

[0088] The protuberances 109 can be dot-shaped protuberances, having a simple geometric shape, for example a truncated pyramidal or truncated-conical shape. The height H109 of the protuberances 109 can be between about 0.4 and about 1.2 mm, preferably between about 0.6 and about 1 mm, even more preferably between about 0.7 and 0.9 mm. In some embodiments, the height H109 can be substantially equal to the height H105 of the protuberances 105.

[0089] In some embodiments, the distribution density of the protuberances 109 may be approximately equal to the density of the protuberances 105. For example, the protuberances 109 may have a density between about 10 and about 80, preferably be- tween about 30 and about 60 protuberances/cm² in the bands 114. [0090] In advantageous embodiments, the protuberances 109 and the protuberances 105 are arranged according to a tip-to-tip arrangement, so that the adhesive C applied to the ply VI at the protuberances 105 glues the ply VI against areas of the ply V2 embossed by the embossing protuberances 109. In the nip between the embossing rollers 23 and 31 there can be a rolling pressure between the protuberances 109 and the protuberances 105, to obtain mutual adhesion of the two plies VI, V2.

[0091] Fig. 23 shows a schematic section of a portion of web material N obtained by the machine 100. The plies VI, V2 have embossed protrusions, each of which is marked in Fig. 23 with the letter "P" followed by a number corresponding to the ref- erence numeral indicating the embossing protuberance of the respective embossing roller which has formed the respective embossed protrusion.

[0092] In the illustrated example, the ply VI has, in longitudinal bands marked 102/108/112, and corresponding to the annular bands 102, 108 and 112, embossed protrusions P103 with frontal tips or pixels P103.3, on which a dye can be applied by the distributor 15. In front of the embossed protrusions P103, the ply V2 has em bossed protrusions P107 formed by the embossing protuberances 107 and which form a support for the embossed protrusions P103. The embossed protrusions P103, P103.3 and P107 form longitudinal decorations.

[0093] In the longitudinal bands 114/106/104, which correspond to the annular bands 114, 106 and 104, the ply VI has embossed protrusions P105 formed by the embossing protuberances 105, which are glued at the head by means of glue C to the head of embossing protrusions P109 formed in the same annular band in the ply V2 by the embossing protuberances P109.

[0094] The longitudinal bands 114, 104, 106 are particularly soft and absorbent thanks on the one hand to the calendering performed by the first embossing roller 11 and the first pressure roller 17, and on the other hand to the micro-embossing per formed by the embossing protuberances 105 of the second embossing roller 23.

[0095] In some embodiments, a third intermediate ply can be provided and inserted between the plies VI and V2. The third ply can be smooth. In other embodiments, the third ply can be embossed together with the ply VI, that is, it can follow the same path thereof. In other embodiments, the third ply can be embossed together with the second ply V2. In still other embodiments, the third ply can be micro-embossed in dependently of the plies VI and V2, for example in a further embossing unit indicat- ed with a broken line in Fig. 14, where the third ply is indicated with V3.

[0096] In other embodiments, the third embossing roller 31 can be provided with micro-embossing protuberances 109 on the entire surface, instead of only in the an nular bands 112, eliminating the protuberances 107 of hexagonal shape (in the exam ple). In this case, the micro-embossing formed by the protuberances 109 can define the areas of mutual bonding between the plies VI and V2, at the protuberances 105, and at the same time it can form support areas for the decorative embossed protru- sions P103, formed by the protuberances 103 or similarly by the protuberances 101 (Figs. 15-17).

[0097] Fig. 24 shows a diagram of a further embossing machine 200 for the pro duction of a multi-ply cellulose web material N formed by embossed and bonded plies VI, V2. Same numbers indicate parts identical or equivalent to those illustrated in the above embodiments. In this embodiment, the embossing machine 200 com prises a first embossing unit 3, which can be made like the embossing unit 3 in Fig. 1 or Fig. 14.

[0098] The embossing machine 200 in Fig. 24 has a second embossing unit 5 which is provided only with an embossing roller 31 with embossing protuberances general- ly indicated with reference numeral 33, co-acting with a pressure roller 35, while the embossing roller 23 and relative members coa-acting therewith are lacking.

[0099] In some embodiments of the embossing machine 200, the plies VI and V2 are bonded together by mechanical ply-bonding rather than by gluing. For this pur pose, a series of mechanical ply-bonding wheels 201 can be provided, which are pressed against the embossing roller 11. The mechanical ply-bonding wheels 201 can have a smooth edge and can co-act with embossing protuberances arranged accord ing to bands on the embossing roller 11. For example, the embossing roller 11 can be provided with an embossing pattern as shown in Fig. 2 or preferably as shown in Fig. 15. The mechanical ply-bonding wheels 201 can be arranged at the bands 53, so as to co-act with the head surfaces of the embossing protuberances 59 or 101 and/or 103 described above. Preferably, the embossing protuberances of the embossing roller 11 have, in this case, small-sized tips which project from the head of larger- si zed protu- berances, as shown specifically in Figs. 3 and 4 for the protuberances 59, and in Figs. 15 and 17 for the protuberances 103. In this way, a high localized pressure is ob- tained, which facilitates bonding by mechanical pressure. The embossing wheels 201 can have a smooth cylindrical peripheral surface.

[0100] When the embossing machine 200 is provided with a distributor 15 of a liq uid colored or colorless substance, this can favor mechanical bonding, thanks to the water applied to the ply VI in the areas on which the pressure by the mechanical ply- bonding wheels 201 is applied. [0101] With the machine 200 shown in Fig. 24, a web material N is obtained in which the mechanical ply-bonding lines are generated at the decorations obtained on the ply VI by the protuberances arranged according to bands on the embossing roller 11. These protuberances, possibly in combination with corresponding embossing protuberances 77 of the roller 31 as shown in Fig. 10 or 107 of Fig. 20, serve to mask and conceal the mechanical deformations generated by mechanical ply-bonding. In practice, therefore, the finished product does not have, as is the case with web mate rials bonded by mechanical ply-bonding of the prior art, bulges in the longitudinal bands in which the mechanical ply-bonding is carried out.

[0102] In this way, a higher quality, aesthetically improved product is obtained, which also has a more uniform thickness, with consequent technical advantages in the subsequent processing steps.

[0103] In the embodiment shown in Fig. 24 the ply V2 is embossed, for example with a continuous micro-embossing or with bands as described for the ply V2 in the above embodiments. In other embodiments, vice versa, the ply V2 can be smooth. For this purpose, it is possible, for example, to provide that the embossing roller 31 remains distanced from the pressure roller 35, or that the unit consisting of the rollers 31 and 35 is not present.

[0104] While in Fig. 24 mechanical ply-bonding is performed with preferably smooth mechanical ply-bonding wheels, which act against the embossing roller 11, in other embodiments an independent mechanical ply-bonding unit can be provided, separate from the embossing unit 3 and therefore from the embossing roller 11. Fig. 25 shows an embodiment of this type. Equal numbers indicate parts that are identical or equivalent to those already described with reference to the above figures, and in particular to Fig. 24. In the diagram in Fig. 25, the machine is generally indicated with reference numeral 300, the mechanical ply-bonding wheels are indicated with reference numeral 301 and co-act with a counter-roller 303. The counter-roller 303 and the mechanical ply-bonding wheels 301 are separated from the embossing roller 11, in the sense that they are not in contact therewith. The embossing roller 11 can be configured as in one of the embodiments described so far. The embossed ply VI in the embossing nip 21 between the embossing roller 11 and the pressure roller 17 is detached from the embossing roller 11 and fed into the mechanical ply-bonding nip formed between the mechanical ply-bonding wheels 301 and the counter-roller 303. Into this nip also the ply V2 can be fed, which can be embossed in the embossing nip 37, or smooth. One or the other or both plies VI, V2 can be formed by a single layer or by several superposed layers. [0105] The mechanical ply-bonding wheels 301 can have a smooth edge, or a knurled edge, or can be provided with small protuberances, so as to reduce the area of contact with the counter-roller 303. In this way, a higher pressure is obtained, with the same thrust between mechanical ply-bonding wheels 301 and counter-roller 303, and therefore a more effective bonding between the plies. [0106] In Fig. 25 the colored liquid distributor 15 has been omitted, but it is to be understood that a distributor 15 can be provided in the embossing machine 300 as well, for example to generate a colored decoration and/or to humidify the cellulose material which forms the ply VI and therefore improve the bond obtained by me chanical pressure. [0107] Fig. 26 shows a further embodiment of an embossing machine, indicated as a whole with reference numeral 400. The structure of this machine is similar to that of the embossing machine 1 in Fig. 1. Equal numbers indicate parts identical or cor responding to those already described. In particular, the embossing rollers of the two embossing units 3, 5 can be configured as described with reference to Fig. 1, or al- ternatively as described with reference to Fig. 14.

[0108] The main difference between the embossing machine in Fig. 26 and the em- bossing machines in Figs. 1 and 14 consists in that in Fig. 26, bonding between the plies VI, V2 is performed by means of a mechanical ply-bonding unit comprising mechanical ply-bonding wheels 401 co-acting with a counter-roller 403. The glue dispenser can therefore be omitted. The ply VI can thus in this way be embossed in the embossing nip 29 without receiving adhesive, but solely to impart other tech nical-functional features to the product, for example a greater thickness and/or a greater absorption capacity. The plies VI and V2 are then mechanically ply-bonded by the ply-bonding wheels 401 and by the counter-roller 403, which can preferably be made as already described with reference to the mechanical ply-bonding unit 301, 303 in Fig. 25.

[0109] In all the embodiment of Figs. 24 to 26, the embossing roller 11 and the pressure roller 17 generate on the ply VI embossed bands (usually narrower) sepa rated by bands (usually wider than the previous ones) in which the cellulose material of the ply VI is calendered between a smooth cylindrical surface of the embossing roller 11 and the smooth cylindrical surface of the coating 17R of the pressure roller 17.

[0110] Fig. 27 shows a schematic representation of a roll R made of wound web material N. A portion of the web material is unwound to show how it is formed by sheets F connected to one another along perforation lines LT, by a perforating unit known per se. Bl and B2 indicate the longitudinal edges of the web material N ob tained by cutting a log by means of a log saw for dividing the log into individual rolls R. As mentioned above, the cut can be made at the dotted lines T shown in Figs. 2 and 15. In this way, the bands 53, 65, 73 decorated by the protuberances of the em bossing roller 11 are located at a certain distance from the edges Bl, B2. If the web material N is obtained by gluing the plies VI, V2 (and possibly other plies V3, etc. which constitute it), the adhesive can be applied on embossing protuberances gener ated by the embossing roller 23 up to the edges Bl, B2, and up to the perforation lines LT, so that the plies are effectively bonded to one another along the edges of each sheet F. If, on the other hand, the plies are bonded together by mechanical ply- bonding, the ply junction area can be a certain distance from the edges Bl, B2 as it happens in the products of the prior art, but (contrary to the known products), the mechanical ply bonding lines do not negatively influence the aesthetic and functional features of the finished article. In all cases, the outer ply is the calendered one. [0111] Figs. 28 to 31 show summary and illustrative block diagrams of methods described herein.

[0112] While the invention has been described in terms of various specific embod- iments, it will be apparent to those skilled in the art that various modifications, changes and omissions are possible without departing from the spirit and scope of the claims. Moreover, unless otherwise specified, the order or sequence of any process step or method can be varied or re-arranged according to alternative embodiments.

[0113] Furthermore, innovative aspects of the methods described herein are defined in the following clauses:

[0114] Clause 1 :

A method for producing a multi-ply cellulose web material of tissue paper, comprising the following steps:

- feeding a first ply into an embossing nip, between a first embossing roller and a first pressure roller (17)

- embossing the first ply (VI) in the first embossing nip (21) along longitu- dinal embossing bands (53; 102) extending in the longitudinal direction of the first ply (VI) and calendering the first ply (V2) in longitudinal calen dering bands (51; 104) interposed between the longitudinal embossing bands

- bonding the first ply (VI) to a second ply (V2) and forming a multi-ply web material (N)

- forming a roll (R) with the web material (N).

[0115] Clause 2:

A method for producing a multi-ply cellulose web material of tissue paper, com prising the following steps:

- feeding a first ply into a first embossing nip (21), between a first embossing roller (11) and a first pressure roller (17)

- embossing the first ply (VI) in the first embossing nip (21) along longitudinal embossing bands (53; 102) extending in the longitudinal direction of the first ply (VI) and calendering the first ply (V2) in longitudinal calendering bands (51; 104) interposed between the longitudinal embossing bands - bonding the first ply (VI) to a second ply (V2) and forming a multi -ply web material (N)

- winding the web material in a log

- dividing the log into rolls (R) by cutting lines arranged at longitudinal calen dering bands.

[0116] Clause 3

- embossing the first ply (VI) in the first embossing nip (21) along longitudinal embossing bands (53; 102) extending in the longitudinal direction of the first ply (VI) and calendering the first ply (V2) in longitudinal calendering bands (51; 104) interposed between the longitudinal embossing bands

- embossing the first ply (VI) in a second embossing nip (38) between a sec ond embossing roller (23) and a second pressure roller (27) along the longitu dinal calendering bands (51; 104) and applying a glue on embossed protru sions (P61; P105) formed in the calendering bands

- bonding by gluing the first ply (VI) to a second ply (V2) and forming a mul ti-ply web material (N)

- winding the web material in a log

- dividing the log into rolls (R) by cutting lines arranged at longitudinal calen dering bands

[0117] Clause 4

- embossing the first ply (VI) in the first embossing nip (21) along longitudinal embossing bands (53; 102) extending in the longitudinal direction of the first ply (VI) and calendering the first ply (V2) in longitudinal calendering bands (51; 104) interposed between the longitudinal embossing bands - bonding the first ply (VI) to a second ply (V2) by mechanical ply bonding along the longitudinal embossing bands (53; 102) and forming a multi -ply web material (N)

- forming a roll (R) with the web material (N). [0118] Clause 5:

An embossing machine (1; 100; 200; 300; 400), comprising:

- a first embossing roller (11) provided with embossing protuberances (57; 59;

101; 103) distributed according to first annular bands on a lateral surface of the embossing roller (11), between which there are interposed second annular bands without embossing protuberances;

- a first pressure roller co-acting with the first embossing roller for embossing and calendering a first ply (VI) of web material;

- a first path for the first ply (VI) extending through a first embossing nip (21), between the first embossing roller (11) and the first pressure roller (17). [0119] Clause 6:

An embossing machine according to clause 5, further comprising a mechanical ply bonding unit.

[0120] Clause 7:

An embossing machine according to clause 5, comprising a second embossing roller (23) co-acting with a second pressure roller (27) and defining therewith a second embossing nip (29), through which the path of the first ply (VI) extends; and wherein the second embossing roller (23) comprises embossing protuberanc- es (61; 105) arranged in line with the annular bands without embossing protuber ances of the first embossing roller (11). [0121] Clause 8:

Embossing machine according to clause 7, comprising a glue distributor (26) co- acting with the second embossing roller (23) for applying a glue (C) on embossed protrusions of the first ply (VI) formed by the second embossing roller (23).

[0122] Clause 9:

Embossing machine according to clause 7 or 8, further comprising a third em bossing roller (31), co-acting with a third pressure roller (35) and defining a third embossing nip (37) therewith, through which a feed path of the second ply (V2) extends, said feed path of the second ply (V2) converging with the feed path of the first ply (VI) downstream of the second embossing nip (29).

[0123] Clause 10:

Embossing machine according to clause 9, wherein the third embossing roller

(31) has first annular bands provided with embossing protuberances (75) ar ranged in phase with the annular bands provided with protuberances (61) of the second embossing roller (23).

[0124] Clause 11 :

Embossing machine according to clause 10, wherein the third embossing roller (31) comprises second annular bands, interposed between the first annular bands, wherein the second annular bands are provided with embossing protuberances (77) of larger cross-sectional dimensions than the embossing protuberances (75) arranged in the first annular bands, the second annular bands of the third emboss- ing roller (31) being in phase with the annular bands without embossing protu- berances (61) of the second embossing roller (23).

[0125] Clause 12:

Embossing machine according to one or more of the clauses 5 to 11, further comprising a distributor of a liquid co-acting with the first embossing roller (11), adapted to apply a liquid on embossed protrusions generated on the first ply (VI) by the first embossing roller (11).

[0126] Clause 13:

Embossing machine according to one or more of the clauses 5 to 12, comprising a path for a third ply (V3) of web material, which path of the third ply converges towards the path of the first ply (VI) downstream of the first embossing roller (11).

Claims

1. A method for producing a multi-ply cellulose tissue paper web ma- terial, comprising at least a first ply (VI) and a second ply (V2) bonded to each oth er, wherein the first ply (VI) is fed between an embossing roller (11) and a first pres- sure roller (17), wherein the embossing roller (11) is provided with embossing protu- berances (57; 59; 101; 103) distributed according to first annular bands on a lateral surface of the embossing roller (11), between which there are interposed second an nular bands without embossing protuberances; and wherein the first ply (VI) is em bossed along longitudinal embossing bands (53; 102), and calendered along longitu- dinal calendering bands (51; 104), as a result of co-action of the embossing roller (11) with the pressure roller (17).

2. The method of claim 1, wherein the protuberances of the first em bossing roller are pressed against a yielding coating (17R) of the first pressure roller (17), the first ply (VI) being embossed as a result of penetration of the embossing protuberances (57; 59; 101; 103) of the first embossing roller (11) in the yielding coating (17R) of the first pressure roller (17); and wherein the first ply is calendered along the longitudinal calendering bands through co-action of the first embossing roller with the surface of the yielding coating (17R) of the first pressure roller (17).

3. The method of claim 1 or 2, comprising the step of applying a liq- uid to embossed protrusions (P59; P101; P103) formed in the first ply (VI) by the embossing protuberances (57; 59; 101; 103) of the first embossing roller (11) by means of a distributor (15) co-acting with the first embossing roller (11).

4. The method of claim 3, wherein said liquid is a colored liquid.

5. The method of one or more of the preceding claims, wherein the second ply (V2) is bonded to the first ply (VI) by gluing.

6. The method of one or more of the preceding claims, wherein the first ply (VI) and the second ply (V2) are bonded together by mechanical ply bond ing.

7. The method of one or more of the preceding claims, further com- prising the step of embossing the first ply (VI) along the longitudinal calendering bands.

8. The method of claim 7, wherein the step of embossing the first ply (VI) along the longitudinal calendering bands (51; 104) comprises the step of pass- ing the second ply (VI) between a second embossing roller (23) and a second pres- sure roller (27).

9. The method of claim 7 or 8, further comprising the steps of: apply- ing a glue (C) to embossed protrusions (P61; 105) formed on the first ply (VI) in the longitudinal calendering bands (51; 104); and gluing the first ply (VI) to the second ply (V2) by means of said glue (C).

10. The method of one or more of the preceding claims, further com prising the step of embossing the second ply (V2) before bonding to the first ply (VI).

11. The method of claim 10, wherein the step of embossing the second ply (V2) comprises the step of generating embossed protrusions (P75; P109) on lon- gitudinal bands (71; 114) of the second ply (V2) aligned with the longitudinal calen dering bands (51; 104) of the first ply (VI).

12. The method of claim 11, wherein the first ply (VI) and the second ply (V2) are bonded together by gluing along the longitudinal calendering bands (51; 104) through glue (C) applied on embossed protrusions (P61; P105) of the first ply (VI) positioned in the longitudinal calendering bands (51; 104), which are combined in a nested configuration or in a tip-to-tip configuration with embossed protrusions (P75; P109) of the second ply.

13. The method of one or more of the preceding claims, wherein the second ply (V2) is embossed along longitudinal bands aligned with the embossed longitudinal bands (53: 102) of the first ply, with formation of embossed protrusions (P77; P107) that are positioned facing the embossed protrusions (P57; P59; P101; P103) formed in the first ply (VI) along the longitudinal embossing bands.

14. A multi-ply cellulose web material, comprising at least a first ply (VI) and a second ply (V2) bonded to each other, wherein the first ply (VI) compris- es longitudinal calendering bands (51; 104) interposed between longitudinal emboss- ing bands (53; 102).

15. The web material of claim 14, comprising a coloring on embossed protrusions (P59; P101; P103) of the first ply (VI).

16. The web material of claim 14 or 15, wherein the first ply (VI) and the second ply (V2) are bonded to each other by gluing.

17. The web material of one or more of claims 14 to 16, wherein the first ply (VI) and the second ply (V2) are bonded to each other by mechanical ply bonding.

18. The web material of claim 17, wherein the first ply (VI) and the second ply (V2) are bonded to each other by mechanical ply bonding along the longi tudinal embossing bands.

19. The web material of one or more of claims 14 to 18, wherein the longitudinal calendering bands are provided with embossed protrusions (P61; P105).

20. The web material of claim 19, wherein the embossed protrusions (P61; P105) along the calendering bands have a smaller transverse dimension than embossed protrusions (P57; P59; P101; P103) arranged along the embossing bands of the first ply (VI).

21. The web material of claim 19 or 20, wherein the first ply (VI) is glued to the second ply (V2) through glue (C) applied to head surfaces of the em- bossed protrusions (P57; P59; P101; P103) arranged along the embossing bands of the first ply (VI).

22. The web material of one or more of claims 19 to 21, wherein the second ply (V2) comprises longitudinal bands comprising embossed protrusions (P75; P109) arranged in a nested or a tip-to-tip configuration with respect to the em- bossed protrusions (P57; P59; P101; P103) arranged along the embossing bands of the first ply (VI).

23. The web material of one or more of claims 14 to 22, wherein the second ply comprises embossed longitudinal bands, arranged at the embossed longi- tudinal bands of the first ply (VI) and along which there are arranged embossed pro- trusions (P77; P107) forming a support for embossed protrusions (P57: P59) ar ranged along the longitudinal embossing bands of the first ply.

24. The web material of claim 23, when dependent at least on claim 22, wherein the embossed protrusions (P77; P107) of the second ply (V2) arranged at the embossing bands of the first ply (VI) have a larger transverse dimension and a lower density than the embossed protrusions (P75; P109) arranged in nested or tip-to-tip configuration with respect to the embossed protrusions (P57; P59; P101; P103) ar ranged along the embossing bands of the first ply (VI).

25. The web material of one or more of claims 14 to 24, comprising a third intermediate ply (V3) between the first ply (VI) and the second ply (V2), said third ply being smooth or preferably embossed, in particular micro-embossed.

26. An embossing machine (1; 100; 200; 300; 400), comprising:

- a first embossing roller (11) provided with embossing protuberances (57; 59;

- a first pressure roller (17) co-acting with the first embossing roller for em bossing and calendering a first ply (VI) of web material;

- a first path for the first ply (VI) extending through a first embossing nip (21), between the first embossing roller (11) and the first pressure roller (17).

27. The embossing machine of claim 26, further comprising a mechan ical ply bonding assembly, preferably comprising mechanical ply bonding wheels positioned in line with the first annular bands of the first embossing roller (11).

28. The embossing machine of claim 26 or 27, comprising a second embossing roller (23) co-acting with a second pressure roller (27) and defining therewith a second embossing nip (29), through which the path of the first ply (VI) extends; and wherein the second embossing roller (23) comprises embossing protu berances (61; 105) arranged in line with the annular bands without embossing protu berances of the first embossing roller (11), and preferably comprising annular bands without embossing protuberances, in line with the annular bands provided with em- bossing protuberances of the first embossing roller (11); and preferably comprising a glue distributor (26) co-acting with the second embossing roller (23) to apply glue (C) to the first ply (VI) at the embossing protuberances of the second embossing roller (23).

29. The embossing machine of claim 28, further comprising a third embossing roller (31), co-acting with a third pressure roller (35) and defining there- with a third embossing nip (37), through which a feed path of the second ply (V2) extends, said feed path of the second ply (V2) converging with the feed path of the first ply (VI) downstream of the second embossing nip (29); wherein the third em- bossing roller (31) preferably has first annular bands provided with embossing protu- berances (75) arranged in line with the annular bands provided with protuberances (61) of the second embossing roller (23) and preferably second annular bands, inter calated between the first annular bands, wherein there are preferably provided em bossing protuberances of transverse dimension larger than the embossing protuber- ances of the first annular bands, and positioned in alignment with the annular bands without embossing protuberances of the second embossing roller (23).