EP1772257A2

EP1772257A2 - Embossing-laminating device, and multiply embossed product

Info

Publication number: EP1772257A2
Application number: EP06425692A
Authority: EP
Inventors: Mauro Gelli
Original assignee: Fabio Perini SpA
Current assignee: Fabio Perini SpA
Priority date: 2005-10-10
Filing date: 2006-10-09
Publication date: 2007-04-11
Also published as: EP1772257A3; ITFI20050212A1

Abstract

Described herein is an embossed multiply paper-sheet material, comprising at least one first ply and at least one second ply joined to one another by gluing, in which the first ply (V1) and the second ply (V3) have first protuberances and second protuberances (301 P, 101 P) oriented towards the inside of the weblike material, at least some of the first protuberances of the first ply corresponding to some of the second protuberances of the second ply. At least some of said first and second protuberances are elongated in longitudinal directions that intersect one another so that protuberances that correspond to one another are in mutual contact and glued in an intermediate area of their longitudinal development.

Description

Technical field

The present invention relates to improvements to so-called embossing and laminating devices, i.e., devices that perform embossing of two or more plies of paper and join them by means of glue application and lamination.
The invention also relates to improvements to embossed weblike materials, especially with a tissue-paper base, of the multiply type, i.e., comprising at least two plies joined to one another, typically and preferably by gluing.

State of the art

Embossing is one of the operations that are typically carried out on plies or sheets of tissue paper for the production of paper articles for cleaning and personal hygiene, or also for commercial or industrial use, such as, for example, toilet paper, paper wipes, paper napkins and handkerchiefs, and the like.
Embossing is an operation that is carried out for the dual purpose of improving the characteristics of aesthetic appearance and of increasing the functional characteristics, such as, in particular, softness, smoothness, absorbing capacity, or the thickness of the finished material.
Normally, a material made of tissue paper, such as paper wipes and toilet paper, is made up of two or more plies of paper that are embossed separately and then joined to one another via application of glue and lamination of the plies between counter-rotating rollers, which define between them a lamination nip.
Embossing is typically carried out by making each ply to pass between an embossing roller, equipped with protuberances, and a pressure roller with an outer surface coated with compliant material, typically rubber. The process is in this case referred to as "steel-rubber embossing" given that the embossing roller is typically made of steel. In some cases, embossing is carried out between two rollers made of steel or other hard material, one provided with protuberances and the other with corresponding recesses. The protuberances of the embossing roller generate corresponding protuberances or projections in the paper ply. The protuberances formed in the two outermost plies are oriented towards the inside of the finished product.
According to a possible technique (referred to as "tip-to-tip" technique), the two plies of the weblike paper material are joined together by bringing the protuberances of one ply to correspond with the protuberances of the other ply, after prior application of a glue on the protuberances of one of the two plies, or on at least part thereof. In practice, two embossing rollers that emboss two plies of paper separately by means of respective pressure rollers form between them a lamination nip, passing through which are the two embossed plies, before they are detached from the rollers themselves. In the lamination nip, the protuberances of one roller coincide with the protuberances of the other, and the distance between the rollers is such as to cause a localized compression of the plies in positions corresponding to said protuberances.
A tip-to-tip embosser for obtaining a product of this type is described in US-A-3,414,459 . The tip-to-tip embossing technique has undergone progressive improvements in order to solve particular problems that arise with this processing method. Described, for example, in US-A-5,096,527 is a technique for reducing the vibrations and wear in tip-to-tip embossing units. US-A-6,113,723 describes a distribution of protuberances having the purpose of increasing the gluing resistance via a particular arrangement of the protuberances. US-A-5,736,223 describes a method for the production of a paper product made in sheets comprising three plies of tissue paper.
US-A-5,173,351 , US-A-6,032,712 , US-A-6,245,414 , and US-A-6,053,232 describe embossing-laminating units that, by adopting particular measures, prevent a concentrated wear of the protuberances even when these do not coincide completely, but rather give rise to a correspondence over areas, between some of the protuberances of one roller with some of the protuberances of the other. US-A-3,961,119 describes a tip-to-tip embossing unit, in which two embossing rollers co-operating with one another are equipped with helical projections. The projections of one embossing roller present protrusions that mesh with cavities made in the helical projections of the opposed embossing roller.
According to a different technique, the two plies are embossed separately, each between one embossing roller and a counter-roller or pressure roller. The two plies are then glued to one another in such a way that the protuberances of one ply nest between the protuberances of the other. This type of embossing is referred to as "nested" embossing. The lamination of the two plies is obtained between one of the embossing rollers and a laminating roller, whilst the two embossing rollers do not come into contact with one another. Examples of embossing-laminating devices of this type are described in US-A-3,556,907 , US-A-3,867,225 , and US-A-5,339,730 .
US-A-5,686,168 describes a method of nested embossing, in which the plies are joined by lamination between two opposed embossing rollers.
The documents Nos. US-A-6,578,617 and US-A-6,470,945 described embossing units that can carry out an embossing according to both of the technologies illustrated above. In order to pass from an embossing of a tip-to-tip type to an embossing of a nested type, it is possible to modify the angular phase and/or axial position of the two embossing rollers.
The document No. US-A-6,261,666 describes a similar device for carrying out alternatively a tip-to-tip embossing or a nested embossing. Another similar device is described in US-A-6,109,326 .
Initially, embossing was obtained according to very simple geometrical patterns, with uniform distributions of frusto-conical or frusto-pyramidal protuberances. Said embossings mainly had a technical function, having the purpose of providing a product of adequate thickness and with a sufficient softness, as well as absorption capacity.
Currently, embossing is increasingly required to fulfill a dual purpose, namely both a technico-functional one and an aesthetic one. There have consequently been developed embossing patterns and embossing devices that will enable a product to be obtained that is pleasant from the aesthetic point of view and at the same time suitable for meeting the increasingly high aesthetic and commercial requirements demanded of these products. Embossing is no longer obtained only by means of elementary geometrical patterns, but envisages the combination of embossings that are more or less dense (sometimes micro-embossings) and embossed and possibly printed decorative patterns. Examples of complex embossings are described in US-A-6,136,413 ; US-A-5,846,636 ; and US-A-6,106,928 .
A new embossing technique that enables decorations to be obtained which are of particularly high quality and are readily interchangeable is described in US-A-6,755,928 and US-A-6,681,826 .
One of the problems that are encountered in embossing processes, in particular in the tip-to-tip technique, derives from the difficulty of aligning the protuberances of the two embossing rollers. This difficulty is particularly marked in the case of small protuberances and hence very fine and complex patterns.
A further problem that is encountered working with the tip-to-tip technique is represented by the lack of flexibility in the choice of the decorations in so far as, up to now, one embossing roller has always been opposed by just one other roller; i.e., the decorations are made so that one roller can work coupled just to one other very precise roller, which is not interchangeable. It is thus not possible to replace the pattern on one side of the multiply weblike material, without also changing the pattern on the other face.

Objects and summary of the invention

According to a first aspect, an object of the present invention is to provide an embossing and lamination device that will enable a more convenient adjustment and smaller difficulties of phasing between the embossing rollers.
According to a different aspect, an object of the present invention is to provide a tip-to-tip embossed multiply paper product that is easier to produce, with smaller difficulties in phasing of the machinery for its production.
An object of an improved embodiment of the invention is to provide a device that will enable production of an embossed multiply product alternatively according to the tip-to-tip technique or according to the nested technique.
A further object of the present invention is to provide rollers which, also in tip-to-tip operations, will enable interchangeability of one roller with the other; i.e., they will enable tip-to-tip operation between a first roller and a second interchangeable roller.
Basically, according to a first aspect, the invention relates to an embossing and laminating unit for the production of an embossed weblike material comprising at least two plies embossed separately and then coupled to one another, said unit comprising a first embossing roller with first embossing protuberances and a second embossing roller with second embossing protuberances, said embossing rollers defining a nip between them, passing through which are said at least two embossed plies, it being possible for said embossing rollers to be phased with respect to one another in such a way that, in said nip, at least some of the first protuberances correspond to at least some of the second protuberances in a tip-to-tip configuration. Characteristically, at least some of said first protuberances are elongated in a first longitudinal direction, and at least some of said second protuberances are elongated in a second longitudinal direction, said longitudinal directions being oriented in such a way that in the nip between said two rollers, the longitudinal directions of the first protuberances and of the second protuberances intersect.
With an arrangement of this type it is possible to obtain an embossed weblike material with at least two plies, in which the protuberances on the two plies arrange themselves in a tip-to-tip configuration, i.e., with the protuberances of one ply corresponding to the protuberances of the opposite ply, without the need for a precise phasing of the embossing rollers. There is in fact a tolerance in the axial and angular phasing of the embossing rollers that is all the greater, the greater the principal dimension (i.e., along the longitudinal extension) of the various protuberances. Protuberances elongated in non-parallel directions remain in tip-to-tip configuration even though they do not cross one another perfectly in the middle line when the two embossing rollers are not perfectly in phase.
There follows the possibility of obtaining a product of high quality, with tip-to-tip embossing, without the burdens of adjustment that usual tip-to-tip embossing units require.
According to an advantageous embodiment, the protuberances are made in such a way that they can be brought also into the nested configuration, preferably with an angular staggering instead of an axial staggering of the two rollers. This renders the design and construction of the supports of the rollers simpler.
According to a different aspect, the invention relates to a material made of a multiply embossed paper sheet, comprising at least a first ply and at least a second ply, joined to one another by gluing, in which said first ply and said second ply have first protuberances and second protuberances, oriented towards the inside of the weblike material, at least some of the first protuberances of the first ply corresponding to some of the second protuberances of the second ply, said material being characterized in that at least some of said first and second protuberances are elongated in longitudinal directions that intersect one another so that protuberances that correspond to one another are in mutual contact and glued in an intermediate area of their longitudinal development.
According to another aspect, the invention relates to an embossing and laminating unit for the production of an embossed weblike material comprising at least two plies embossed separately and coupled to one another, comprising a first embossing roller with first embossing protuberances and a second embossing roller with second embossing protuberances, said embossing rollers defining a nip between them, passing through which are said at least two embossed plies, said unit being characterized in that at least some of said first protuberances have a linear development and surround areas in which, in the said nip, protuberances of the second roller insert,. There are thus obtained weblike materials of large volume, i.e., very puffed up or swollen, and hence presenting a considerably high aesthetic quality, as well as characteristics of greater softness and absorption. By interspersing protuberances of the second ply between linear protuberances of the first ply, a resting surface is obtained that prevents collapsing of the swollen areas of the ply embossed with the linear embossings.
A further aspect of the invention regards a multiply embossed-paper sheet material, comprising at least a first ply and at least a second ply, joined to one another by gluing, in which said first ply and said second ply have first protuberances and second protuberances oriented towards the inside of the weblike material, said material being characterized in that said first protuberances have a linear development and surround areas of the first ply forming swellings projecting towards the outside of the sheet material.
Further advantageous characteristics and embodiments of the weblike material and of the embossing unit according to the invention are described in what follows with reference to some illustrative and non-limiting examples of the invention and are defined in the attached claims.

Brief description of the drawings

A better understanding of the invention will emerge from the ensuing description and the annexed drawings, which show practical non-limiting embodiments of the invention. More in particular, in the drawings:

Figure 1 a schematic side view of an embossing-laminating device on which the present invention can be applied;
Figure 2 shows a development in the plane of a first embossing pattern of one of the two embossing rollers;
Figure 3 shows a development in the plane of a second embossing pattern for the other of the two embossing rollers;
Figures 2A and 3A show schematic sections according to the lines IIA-IIA and IIIA-IIIA of Figures 2 and 3, respectively;
Figure 4 shows the superposition of the plies embossed in tip-to-tip mode with the patterns of Figures 2 and 3;
Figure 5 shows the superposition of the plies embossed in nested mode with the patterns of Figures 2 and 3;
Figures 4A and 5A show schematic local sections according to the lines IVA-IVA and VA-VA of Figures 4 and 5, respectively;
Figure 6 shows an alternative to the pattern of Figure 2;
Figure 6A shows an enlargement of a detail of Figure 6;
Figure 7 shows an alternative to the pattern of Figure 3;
Figure 7A shows an enlargement of a detail of Figure7;
Figures 8 and 9 show variants to the pattern of Figure 6;
Figure 10 shows an alternative pattern for the protuberances of the two embossing rollers;
Figure 10A shows a cross section according to the line XA-XA of Figure 10;
Figure 10B shows a cross section according to the line XA-XA of Figure 10 in a modified embodiment;
Figure 11 shows a schematic perspective view of a weblike material made of two plies obtained with rollers etched according to the pattern of Figures 10 and 10A;
Figure 12 shows a variant of the pattern of Figure 10;
Figure 13 shows a schematic view of a weblike material formed by two plies embossed and coupled using the etchings of Figure 12;
Figure 14 shows a variant of the pattern of Figure 13;
Figure 14A shows an enlarged detail of Figure 14;
Figure 15 shows a pattern of etching for a second roller designed to co-operate with a roller etched according to the pattern of Figure 14;
Figure 15A shows an enlarged detail of Figure 15;
Figure 16 shows a pattern alternative to the pattern of Figure 15;
Figure 16A shows an enlarged detail of Figure 16;
Figures 17 and 18 show an alternative embodiment for the patterns of etching of a pair of rollers according to the invention;
Figure 19 shows, in an enlarged detail, the superposition of the two patterns of Figures 17 and 18;
Figures 20 and 21 show a development in the plane of portions of a cylindrical surface of two embossing rollers in a different embodiment;
Figure 20A shows a local and very enlarged cross section according to the line A-A of Figure 20;
Figure 22 shows an enlarged detail of the superposition of the embossing patterns of the two rollers represented in Figures 20 and 21;
Figure 22A shows a very enlarged local cross section according to the line B-B of Figure 22; and
Figure 23 shows a schematic plan view of protuberances similar to those of Figure 20, but with a continuous and completely closed configuration.

Detailed description of preferred embodiments of the invention

Figure 1 shows a diagram of an embossing-laminating unit, designated as a whole by 2, comprising a first embossing roller 1 and a second embossing roller 3, rotating about respective axes of rotation 1A and 3A. f1 and f3 indicagte the directions of rotation. Defined between the two embossing rollers is a nip G, passing through which are two plies of tissue paper V1 and V3, separately embossed by the rollers 1 and 3, respectively. Embossing is obtained by causing each of the plies to pass between the respective embossing roller 1 or 3 and a corresponding pressure roller 5 or 7, where 5A and 7A designate the axes of rotation. The rollers 5 and 7 are coated with a layer of yielding material, for example rubber or the like, in which protuberances with which the embossing rollers 1 and 3 are equipped penetrate, said protuberances being hereinafter designated as a whole by 1 P and 3P in Figure 1. Possible configurations of these protuberances will be described in detail in what follows.
In a way known per se, the two rollers 1 and 3 can be phased so as to bring the protuberances 1 P and 3P into a tip-to-tip configuration or else into a nested configuration. In the first condition, in the lamination nip G at least some of the protuberances of the roller 1 correspond to protuberances of the roller 3, and the distance between the rollers 1 and 3 is such that a pressure is exerted between the protuberances sufficient to cause lamination and gluing together of the plies V1 and V3. In the second condition, the protuberances 1P are interspersed between the protuberances 3P. In this case, the mutual adhesion between the two plies V1 and V3 is obtained by lamination between the embossing roller 1 and a laminating roller 13. Designated by Nn and Npp are the two alternative paths of the weblike material N formed by the two plies V1 and V3, said paths being different according to whether the material is processed with the tip-to-tip technique (path Npp) or else with the nested technique (path Nn).
Designated as a whole by 17 is a glue-dispensing unit, which applies a glue on the radially most projecting surfaces of the ply V1 embossed by the roller 1, when said ply is still engaged to the surface of said roller 1.
Adjustment of the rollers 1 and 3 in order to operate in the tip-to-tip condition or in the nested condition can be obtained in a way known per se, via adjustment of the angular phase between the two rollers 1 and 3, or else via mutual displacement in the axial direction, or else with the two movements combined with respect to one another. The mechanical members and, in particular, the supports for the rollers 1 and 3 that enable this adjustment are in themselves known and will not be described in detail herein.
Figures 2 and 3 show a development in the plane of a portion of the cylindrical surface of the two embossing rollers 1 and 3 in a first possible embodiment. Since the protuberances made on these rollers correspond, as regards shape and distribution, to the protuberances that are formed on the plies V1 and V3, Figures 2 and 3 are basically plan views of portions of the plies V1 and V3.
In Figures 2, 2A, 3, and 3A, for reasons of simplicity, as regards the protuberances only the boundaries of the respective front surfaces are shown, it being understood that said protuberances normally have the shape of a truncated cone, i.e., they thin out in the centrifugal radial direction, as is shown in the sections of Figures 2A and 3A.
With reference to Figure 2, which represents, for example, a portion developed in the plane of the embossing roller 1, the protuberances comprise a first series of alignments of protuberances 101P distributed according to helices about the axis of the roller 1. The protuberances 101 P are elongated in the direction of the respective alignments 101A formed by them. In the example illustrated, the alignments 101A of protuberances 101P are arranged in pairs and intersect one another to form rectangular areas within which protuberances 103P of smaller dimensions are arranged. The protuberances 103P have, in particular, a smaller cross section than the protuberances 101 P and also a smaller height. Figure 2A shows a local schematic and enlarged cross-sectional view according to the arrow IIA-IIA of Figure 2. In said cross-sectional view, it may be noted how the height H of the protuberances 101 P is greater than the height h of the protuberances 103P.
In the intersections between the alignments 101A of protuberances 101 P, further protuberances 105P having an irregular shape and height h, equal to the height of the protuberances 103P, are located.
Figure 3 shows a development in the plane of the surface of the embossing roller 3 with the respective protuberances, which correspond as regards shape and distribution to the protuberances that said roller forms on the ply V3. The protuberances on the roller 3 are distributed with a first series of alignments 301A of elongated protuberances 301 P having substantially the same shape (in this example) as the protuberances 101P of the roller 1. However, unlike the protuberances 101 P, the protuberances 301 P are oriented with their major dimension orthogonal to the direction of the alignments 301A of which they form part.
As a result of the above, in the lamination nip G, when the two rollers 1 and 3 are adjusted for tip-to-tip operation, the protuberances 101 P and the protuberances 301 P that correspond to one another, i.e., that find themselves the ones in front of and the others within said nip, arrange themselves with their own major dimensions orthogonal to one another, as will be described more fully with reference to the subsequent Figure 4.
On the surface of the roller 3 there are moreover provided, in the square areas defined by the intersections of the alignments 301A, protuberances 303P having a cross section substantially equivalent to that of the protuberances 103P, but having the same height as the protuberances 301 P. Figure 3A is a schematic and very enlarged cross-sectional view according to the line IIIA-IIIA of Figure 3, in which said difference of dimensions may be noted. It is to be understood that the various figures are indicative and not in scale.
Finally, the reference number 305P designates protuberances of an irregular shape which are arranged in the areas of intersection between the alignments 301A and which also have a height H. Consequently, all the protuberances 301 P, 303P and 305P of the roller 3 have the same height H, i.e., they are as high as the protuberances 101 P of the roller 1.
The alignments 101A and 301A are designed so as to form meshes of equal dimensions. In other words, the median lines of the alignments 101A and 301A, designated by L1 and L3, define on the two rollers 1 and 3 equal lattices.
When the two rollers 1 and 3 provided with protuberances as illustrated in Figures 2, 2A, 3, and 3A are phased so as to operate in tip-to-tip configuration, the protuberances of the roller 1 are superimposed on the protuberances of the roller 3 according to the pattern illustrated in Figure 4. Said Figure illustrates, basically, the superposition of the protuberances obtained on the two plies V1 and V3 laminated in the nip G and glued. Gluing occurs by applying glue on those protuberances on the roller 1 that have a greater radial development 101 P, with height H. Since these protuberances 101 P are arranged according to a lattice defined by the helical lines L1 that is the same as the lattice according to which the protuberances 301 P are arranged, in the lamination nip G mutual contact will be obtained and pressure exerted between protuberances 101P and 301 P. However, unlike what occurs in traditional embossing devices, these protuberances that come into mutual contact, albeit having the same shape, are oriented at 90° with respect to one another so that contact and gluing between the two plies V1 and V3 occurs only in the restricted area of intersection between said protuberances, designated I in Figure 4. It emerges clearly from the figure that a possible slight error of phasing (whether axial, circumferential or both) between the two rollers 1 and 3 does not entail any problem of lamination and gluing, thanks to the elongated shape and to the mutual orientation at 90° between the protuberances 101 P and 301 P of the two rollers 1 and 3. A phasing error (that falls, as order of magnitude, within the longitudinal dimension of the protuberances 101 P, 301 P) simply causes a translation of the area of intersection I along the development of the protuberances, but the mutual contact between said protuberances and hence the lamination between the plies V1 and V3 is in any case obtained.
The protuberances 103P, 105P, 303P, 305P have the function of preventing the two plies V1 and V3 from collapsing in the areas where there is no mutual contact between the protuberances 101P and 103P. An error in phasing of the rollers can entail staggering between these protuberances, which, on the other hand, does not cause any drawback in terms of mutual gluing of the plies.
The ply V1 that receives the glue over the entire front surface of the protuberances 101 P is glued, hence, on a surface that is much greater than the one that will in effect be used for gluing to the ply V3. It follows that, in the finished product, the ply V3 will be softer to the touch and the ply V1 will be stiffer and more absorbent on account of the greater amount of glue. In addition, if a colored glue is used, the ply V1 will be also colored on the entire protuberances 101 P, whilst the ply V3 will be practically colorless or colored only on account of leakage of glue in positions corresponding to the areas of intersection I between protuberances 101 P and 301 P.
There follows a difference between the plies both in technico-functional terms and in aesthetic terms resulting from the different orientation of the protuberances that, on the two plies, give rise to mutual gluing. Figure 4A shows a schematic enlargement of a cross section according to line IVA-IVA of Figure 4 of the weblike material N=V1+V3.
The arrangement and shape of the protuberances 101 P, 103P, 105P, 301 P, 303P, 305P on the two rollers 1 and 3 is such that, with an appropriate phasing of said rollers, it is possible to bring the protuberances into a nested position, i.e., to bring the protuberances of one of the rollers in positions corresponding to the empty spaces between the protuberances of the other. As has been mentioned, said phasing can be obtained with axial displacement or else angular displacement of the rollers. Figure 5 shows the superposition (obtained by radial sliding of one roller with respect to the other) in the nested configuration of the protuberances of the two rollers and hence of the two plies V1 and V3 embossed thereby. Figure 5A shows a highly enlarged local cross section according to the line VA-VA of Figure 5 of the weblike product obtained by coupling the embossed plies V1 and V3.
Figures 6, 6A, 7 and 7A show a modified configuration of the protuberances of the embossing rollers 1 and 3. Reference numbers that are the same designate parts that are the same as or equivalent to those of the previous figures. In particular, Figure 6 shows a development in the plane of a portion of the embossing roller 1, i.e., a portion of the ply V1 embossed by said roller. Designated by 101P are the elongated protuberances arranged according to the alignments 101A along the lines L1; designated by 103P are the protuberances of smaller dimensions arranged in the square areas defined by the alignments 101A; finally, designated by 105P are the protuberances of irregular shape arranged in the areas of intersection between the alignments 101A of protuberances 101P. Figure 6A shows the detailed enlargement of Figure 6.
Figure 7 is the development in the plane of a portion of the corresponding roller 3, i.e., the roller designed to co-operate with the roller 1 configured as in Figure 6. The distribution of protuberances corresponds to the distribution of protuberances on the ply V3 embossed by the roller 3. Reference numbers that are the same designate parts that are the same as those of Figure 3. Figure 7A shows an enlarged detail of Figure 7.
Figures 8 and 9 show developments in the plane of a portion of the cylindrical surface of the embossing roller 1 with a configuration of the protuberances modified with respect to the one illustrated in Figure 6. The rollers configured as illustrated in Figures 8 and 9 co-operate with a roller 3 configured as in Figure 7. Reference numbers that are the same designate parts that are the same as or equivalent to those illustrated in Figure 6. In these two examples of embodiment some of the protuberances 103P arranged in the square areas generated by the intersection of alignments 101A have a circular front surface, whilst others have a lobed front surface.
In addition, in the example of Figure 8, arranged in the areas of intersection of the elongated protuberances 101 P are lobed protuberances with two different shapes. The elongated protuberances 101 P are of two different dimensions, with different lengths in the direction of the principal axis.
As in the example of Figures 2 to 5, also with the etched patterns of Figures 6 to 9 it is possible to get the embossing rollers 1 and 3 to work in the tip-to-tip mode or in the nested mode, thanks to the fact that the protuberances of both of the rollers are configured in such a way that, with appropriate phasing of the rollers, the protuberances of one roller are no longer superimposed on the protuberances of the other, but rather fall in the empty areas between adjacent protuberances. Phasing in one way or the other is obtained, preferably, with an angular staggering of one roller with respect to the other, avoiding the need for any axial staggering, which requires provision of complex supports for at least one of the two embossing rollers.
When the two rollers 1 and 3 are phased to work in the tip-to-tip operating mode, also using the protuberances illustrated in Figures 6 to 9 the advantage is obtained of eliminating the need for accurate adjustments, since (as in the example described previously) the shape and orientation of the elongated protuberances 101P and 301 P is such as to guarantee mutual contact even when the two rollers are only roughly phased. It follows that, with a combination of rollers like the ones described, it is possible to maintain one roller (for example the roller 3 that embosses the bottom ply of the final composite product) and alternate various rollers 1 in order to modify the appearance of the multiply product, the latter being characterized by the top ply, albeit maintaining the dual possibility of producing tip-to-tip or nested rolls. It is also possible to operate in an opposite way, maintaining the top roller fixed and rendering the bottom roller interchangeable, for example in order to maintain the appearance of the roll but modify the technical characteristics thereof, such as thickness or absorbing power.
Figures 10, 10A, 10B, and 11 show a further embodiment of the protuberances on the embossing rollers 1 and 3. Figure 10 shows a portion developed in the plane of the cylindrical surface of one or the other of the rollers 1, 3, which in this case are identical to one another. Figure 10A shows a cross section according to the line XA-XA of Figure 10.
The rollers are surface etched with grooves 402, which define protuberances 401 P with elongated development. The grooves 402 are arranged in sets of six to form square areas of sides A x B. The grooves 402 are oriented with their major dimension according to one or the other of the two directions designated by X and Y in Figure 10. The directions X and Y can correspond to the machine direction and to the cross direction (i.e., respectively, the circumferential direction and the axial direction of the rollers), or else can be inclined, for example and preferably at 45°, with respect to the machine direction and hence with respect to the axis of the respective rollers.
Basically, with these groves, defined on each of the two rollers are "tiles", each of which is formed by a protuberance with quadrangular development along the sides A, B and a series of internal protuberances orthogonal and parallel to said sides. The quadrangular protuberance defines a closed surface of dimensions A x B. The protuberance with quadrangular development could be eliminated, in which case the quadrangular surface A x B would not be delimited by a protuberance but would be defined by bringing up to one another the side-by-side arranged protuberances 401 P formed by grooves 402.
Arranging these two rollers staggered with respect to one another, in such a way that in the lamination nip G each tile A, B with protuberances 401 P aligned in the direction Y will come to coincide with a corresponding tile A, B of the opposite roller with protuberances 401 P aligned according to the direction X, the weblike material N that is obtained has a configuration represented schematically in the perspective view in Figure 11.
Basically, the two plies V1 and V3 have protuberances, once again designated by 401 P, oriented towards the inside of the ply, arranged in sets, and defining a sort of slats or strips arranged to form square areas corresponding to the tiles A, B with orientation of the protuberances 401 P in the two directions X and Y so that in each square area defined by respective and opposed tiles A, B of the two rollers 1, and 3, the protuberances 401 P of one ply are arranged at 90° with respect to the protuberances of the opposed ply 401 P. Each protuberance 401 P of one of the two plies intersects, then, each of the protuberances 401 P of the corresponding square are in the other of the two plies.
If, as in the example illustrated, each square area has seven protuberances or projections, each of these will be in contact in seven points with the corresponding protuberances 401 P of the opposed ply. A high density of gluing points, very close to one another, is thus obtained, which prevent collapsing, i.e., squeezing, of the plies when the weblike material N is wound into a roll. In practice, on each of the two plies V1, V2, the protuberances 401 P facing the inside of the weblike material define, on the two surfaces of the weblike material itself, projections having the shape corresponding to the shape of the grooves 402 of the embossing rollers, said projections on the plies V1 and V2 being again designated 402.
Figure 10B shows a cross section similar to that of Figure 10A, but in an improved embodiment. In this case, it may be noted that the edges at the base and at the distal end of each protuberance 401 P are rounded off and are designated 401A and 401 B, respectively. By rounding off these edges, a similar rounded off configuration of the protuberances is obtained on the embossed weblike material. Rounding-off of the base edges 401A means that the projections 402 on the ply V1 or V3 of the weblike material will be without any sharp edges facing the outside of the weblike material so that this has a smoother appearance without any asperities and hence more pleasant to the touch. The provision of rounded-off edges 401 B does not contribute significantly to the tactile characteristics of the embossed product, but increases appreciably the mechanical strength thereof. This rounded-off conformation of the base and end edges of the protuberances of the embossing rollers can be adopted also in all the other embodiments described, to achieve the same or similar advantages.
On account of the way the embossing-laminating unit 2 is formed, the glue is applied on the protuberances 401 P of just one of the two plies V1 and V3. On this ply, hence, there will be obtained a large amount of glue over all the linear protuberances 401 P and in particular along quadrangular protuberances facing the inside of the weblike material and surrounding each tile of size A x B. Instead, the opposed ply will receive glue only in the approximately square areas of mutual contact between the protuberances 401 P of the two plies V1, V3 in the points of intersection.
If the glue used is colored, this provides a striped decorative effect on the glued ply, with a tiled pattern corresponding to the one visible in Figure 10.
Figure 12 shows a development in the plane of a portion of the cylindrical surface of the rollers 1, 3 in an embodiment slightly modified with respect to the one illustrated in Figures 10 and 10A. Reference numbers that are the same designate parts that are the same as or equivalent to those of the previous example. Designated by MD and CD are, respectively, the machine direction and the cross direction, i.e., the direction of feed of the weblike material (hence the circumferential direction of the rollers 1, 3) and the direction according to which the axes of the embossing rollers 1, 3 are oriented, respectively.
As compared to the embodiment of Figures 10 and 10A, in this case the protuberances 401 P have a curved profile. The sides of the protuberances have a concave pattern: consequently, each protuberance 401 P no longer has the shape of an approximately rectangular strip, but rather has a front surface of variable width, namely, minimum at the center of the protuberance and maximum at the end. The protuberances moreover have a rounded-off cross section so that, on the embossed plies, protuberances will be generated without any sharp edges. As in the case of Figure 10B, also in this embodiment the base and end edges 401A, 401 B of the protuberances 401 P of the embossing rollers can be rounded off for the purposes described above.
Figure 13 shows in a development in the plane a portion of the weblike material N formed by the two plies V1 and V3 superimposed on one another and glued. The discrete areas Z1 represent the points of intersection between the protuberances 401 P of the two plies V1 and V3. These areas are hence those at which gluing of the plies to one another occurs. Designated by Z2 are, instead, areas in which there is a presence of glue applied on the ply V1, but without contact with the ply V3. In these areas, then, there is no mutual gluing of the plies, but a decoration of the glued ply is obtained, in particular when the glue is colored.
The non-rectilinear conformation of the sides of the protuberances 401 P gives rise to a particular decorative effect with variation of the areas glued, as may be noted in Figure 13.
Also in this case, as in the examples of embodiment described previously, the axial and/or angular phasing of the two rollers 1 and 3 is much simpler as compared to a normal embossing-laminating unit of the tip-to-tip type.
In fact, it is not necessary to bring protuberances of small dimensions to coincide with one another, but rather a rough alignment between one tile A, B of one roller with the corresponding tile A, B of the opposed roller is sufficient. The protuberances 401 P of the two rollers within each tile A, B defines (as clearly visible in Figure 13) a plurality of points of gluing in tip-to-tip configuration.
Figure 14 shows a modified embodiment of the pattern illustrated in Figure 12. Figure 14A shows a highly enlarged detail of Figure 14. Reference numbers that are the same designate parts that are the same as or equivalent to those of Figure 12.
In this case, combined to the pattern obtained with the protuberances 401 P arranged in tiles of sides A, B described above, is a decoration represented by a plurality of square areas 404 arranged in a repetitive way and within which curvilinear protuberances 406 are obtained, which form complex decorations.
In this case, unlike what occurs with the pattern of Figure 12, the two rollers 1 and 3 will not be identical to one another, but will differ as regards the configuration of the protuberances 406 and hence the decorative patterns 404 formed by these, once again in order to prevent the need for a precise alignment, i.e., a precise phasing, between the two rollers 1 and 3. If the etching pattern on the roller 1 is the one represented in Figures 14 and 14A, for example, the roller 3 will present an etching of the type shown in Figures 15 and 15A, where the latter shows an enlarged detail of the former. Reference numbers that are the same designate parts that are the same as or equivalent to those of Figures 14 and 14A. The decorations are designated by 404X, and the corresponding protuberances that form them by 406X. The use of protuberances 406 and 406X of different shapes for the two rollers and with a development elongated in directions different from one another enables a tip-to-tip correspondence to be obtained also between these protuberances, without the need for a precise phasing between the rollers 1 and 3. A pair of rollers made with etchings as represented in Figures 14, 14A and 15, 15A, as likewise a pair of rollers made with a pattern of the type illustrated in Figure 12 or in Figure 10 can work only in tip-to-tip configuration on account of the linear development of the protuberances 401 P.
Figure 16 shows a modified embodiment of the roller 3, and Figure 16A shows an enlargement of a detail of Figure 16. The protuberances designed as in Figures 16, 16A can be made on the roller 3 and can co-operate with the protuberances of the roller 1 made as in Figures 14, 14A. In this case, the pair of rollers thus configured can work in tip-to-tip mode or alternatively in nested mode.
In fact, as may be noted in Figures 16, 16A, made on the roller 3 are square areas of size A x B containing alignments L4 and L6 of protuberances of an oval shape, instead of a rectilinear shape. The protuberances 401 P of the opposed roller 1 can, in this way, be interspersed between protuberances 405P of the roller 3. Designated by 404Y are, moreover, decorations formed by distributions of protuberances 406Y, which will come to correspond to the decorations 404 formed by the protuberances 406 illustrated in Figures 14 and 14A.
The protuberances 405P can have, as illustrated in Figure 16A, variable dimensions between the central area and the end of each alignment in order to follow the transverse dimension of the cavities 402 between the linear protuberances 401 P of the roller 1.
In the foregoing description, rollers with etchings arranged according to relatively simple patterns have been illustrated. However, the principle underlying the invention can be implemented also in more complex forms to obtain products with even very elaborate patterns. An example of embodiment of this type is illustrated in Figure 17, 18, and 19.
Figures 17 and 18 illustrate developments in plane of portions of the cylindrical surfaces of the two embossing rollers 1 and 3, respectively. The roller 1 (Figure 17) has a distribution of protuberances similar to that of Figures 2, 6, 8, and 9. On the other hand, in the square areas defined between the lines L1 along which the elongated protuberances 101P are aligned, combinations of intermediate protuberances are arranged, designated once again by 103P, which define wordings and patterns (in the example illustrated a Christmas pattern). In Figure 18 intersecting alignments of protuberances may once again be noted, oriented in a way different with respect to the protuberances of the roller 1. The effect that is obtained by bringing these two rollers to co-operate in a tip-to-tip configuration is shown in Figure 19, where the two patterns are superimposed on one another. Basically, Figure 19 shows an enlarged detail of a development in the plane of the two plies V1, V3 embossed with the rollers 1, 3. It may be noted in Figure 19 how almost all the protuberances of one ply will come to correspond to almost all the protuberances of the other ply. The orientation of the protuberances and their elongated shape means that the correspondence between protuberances of one ply and protuberances of the other will be obtained without any precise phasing between the two rollers, as has already been described in the examples of the previous figures.
Figures 20 to 22 show a further embodiment of the invention. Figure 20 shows a portion developed in the plane of the cylindrical surface of a first embossing roller, designated by 1. It has a series of protuberances 501 having linear development. Characteristically, in this case, the protuberances 501 are configured and arranged so as to enclose partially depressed surface portions 502. By way of example, in the pattern designated by 501X are two symmetrical linear protuberances, which delimit an intermediate surface 502X. Designated by 501Y is a pair of linear protuberances of different shape, which delimit between them a depressed intermediate surface 502Y. Figure 20A shows a schematic and highly enlarged cross-sectional view of two symmetrical protuberances 501 P. In this example of embodiment they have rounded-off base edges 501A and rounded-off end edges 501 B, for the reasons already described with reference to the previous examples of embodiment.
The ply V1 or V3 embossed with an embossing roller having protuberances of the above type will present protuberances facing the inside of the weblike material having a shape corresponding to the protuberances 501 P and projecting outwards, corresponding to the depressed areas or cavities 502, as will be described with reference to the schematic cross-sectional view of Figure 22A.
The roller 3, which co-operates with the roller 1, has a distribution of protuberances 505P of approximately elliptical cross section and of variable sizes and shapes. The shape, size and distribution of the protuberances 505P on the roller 3 are such that, in the nip between the two rollers 1, 3, the protuberances 505P insert within the empty spaces between the protuberances 501 P, with a nested-type configuration.
Figure 22 shows a superposition of the patterns of the protuberances of the two rollers 1 and 3, which can be viewed also as the projection in plan view of the embossing patterns obtained on the two plies V1 and V3 embossed by two rollers. Figure 22A shows a highly enlarged and schematic local cross section of a portion of plies V1 and V3 embossed and coupled to one another, in positions corresponding to the line of section B-B of Figure 22. It may be noted that the ply V1 has protuberances 501 P facing inwards and glued on the internal end so as to adhere to the non-embossed surfaces of the ply V3. The latter has protuberances 505P corresponding to the protuberances 505P of the roller 3 (Figure 21). The height of the protuberances 505P may be the same as or (as in the example illustrated) smaller than the height H of the protuberances 501 P. Basically, the ply V1 has, between thin and elongated inwardly-oriented protuberances 501 P, swellings or projections facing outwards, designated by 502, corresponding to the grooves or depressed areas 502P of the embossing roller 1. These projections or swellings 502 have external rounded-off edges 502B and internal rounded-off edges 502A, corresponding to the rounded-off edges 501 B and 501A (Figure 20A) of the protuberances 501 P on the roller 1.
It may be understood, in particular from Figure 22, which shows the superposition of the embossing patterns of the two plies V1 and V2 and hence of the distribution of protuberances on the two rollers 1 and 3, that in the wide depressed areas 502 defined between protuberances 501 P numerous small protuberances 505P of the opposed roller will come to insert, which in the weblike material V1, V3 form resting surfaces that prevent squeezing of the wide surfaces 502 projecting towards the outside of the weblike material and defining swellings of the material, which are formed as a result of the embossing of the ply V3 via the protuberances 501 P. On the embossed weblike material, the protuberances 505P can have a height equal to or smaller than that of the protuberances 501 P. A weblike material is hence obtained, having a large volume and with a feel, i.e., a tactile effect, that is particularly pleasant thanks to the wide convex protuberances or projections 502 with rounded-off edges 502B, which remain puffy and voluminous even after the weblike material has been, for example, packaged in the form of rolls or folded serviettes, on account of the support provided by the projections 505P. In practice, the projecting portions 502 form a sort of closed or almost closed cells that bestow a considerable volume on the final material. These cells are defined by projections, i.e., swellings, of the plyed material towards the outside of the composite sheet material.
The protuberances 501 P can have a width of between 0.3 and 3 mm, and preferably between 0.5 and 2.5 mm or more preferably 0.5 and 2 mm, and a height of between 0.2 and 3 mm, and preferably between 0.5 and 1.5 mm. When the protuberances have a closed development (example of Figure 23), the linear development of the protuberances 501 P can be, for example, between 5 mm and 50 mm, and preferably between 10 mm and 25 mm. When they have a not completely closed development (Figure 20), each protuberance 501 P can have, for example, a linear development of between 2 and 30 mm, and preferably between 5 and 25 mm. When the protuberances have an interrupted linear development, they still define a perimeter delimiting an area of the weblike material or of the embossed ply. In this case, the area of said perimeter corresponding to the interruptions of the protuberances can be of the order of 25% or less of the overall development of the perimeter. For example, if the protuberances delimit a total perimeter of 40 mm, they can present interruptions for a total length of 20 mm or less. The area enclosed by each closed linear protuberance or by each group of linear protuberances set alongside one another in such a way as to define a substantially closed area can have a perimeter advantageously of between 10 and 100 mm.
The cells or projections 502 that are formed on the weblike material can have dimensions of between 3 and 30 mm, and preferably between 5 and 20 mm.
In the package, the ply V1 will come to be on the outside, usually being the one presenting the more decorated face.
The glue applied on the distal, i.e., front, surfaces of the protuberances of weblike material formed on the protuberances 501 P can be colored to obtain an effect of decorative print in addition to embossing.
In the example illustrated, the protuberances 501 P are of a shape such as to define between them delimited areas 502 that are not completely enclosed in so far as the aforesaid protuberances are interrupted. It is not, however, excluded to make said protuberances 501 P of a continuous and closed shape, for example with a linear development of a circular, polygonal, elliptical or even mixtilinear type, as is, for example, illustrated schematically in Figure 23, in which three different continuous and closed protuberances 501 P are shown, which delimit internal depressed areas 502. In one case, two concentric protuberances are provided.
The embossed weblike material can advantageously be constituted by a variable number of plies of tissue paper, for example even up to five plies, with weight per unit area advantageously of between 12 and 30 g/m² for each ply and between 25 and 110 g/m² for the finished multiply material.
It is to be understood that the characteristics described herein with reference to the various embodiments can be variously combined with one another and that characteristics described with reference to one or more specific examples can be adopted and incorporated also in the other examples of embodiment, thus giving rise to a plurality of possible combinations of characteristics.
It is understood that the drawings show merely examples provided purely as practical demonstration of the invention, it being possible for said invention to vary in shapes and arrangements without thereby departing from the scope of the idea underlying the invention itself. The possible presence of reference numbers in the annexed claims has the purpose of facilitating reading thereof with reference to the description and to the drawings, and in no way limits the scope of protection represented by said claims.

Claims

An embossing and laminating unit for the production of an embossed weblike material comprising at least two plies embossed separately and bonded to one another, comprising a first embossing roller with first embossing protuberances, and a second embossing roller with second embossing protuberances, said embossing rollers defining a nip between them, said two embossed plies passing through said nip, it being possible for said embossing rollers to be phased with respect to one another in such a way that in said nip at least some of the first protuberances correspond to at least some of the second protuberances in a tip-to-tip configuration; characterized in that at least some of said first protuberances are elongated in a first longitudinal direction and at least some of said second protuberances are elongated in a second longitudinal direction, said longitudinal directions being oriented in such a way that in the nip between said two rollers the longitudinal directions of the first protuberances and of the second protuberances intersect.
The embossing and laminating unit according to Claim 1, characterized in that said first and second protuberances are arranged in such a way that, with a phasing of said embossing rollers, they can come to arrange themselves in a tip-to-tip configuration or in a nested configuration alternatively.
The embossing and laminating unit according to Claim 2, characterized in that said phasing for passing from the tip-to-tip arrangement to the nested arrangement is obtained with a mutual angular staggering of the two embossing rollers.
The embossing and laminating unit according to Claim 1 or 2 or 3, characterized in that said first protuberances and said second protuberances elongated in said longitudinal directions are arranged on the first roller and on the second roller according to helical alignments that intersect one another in said nip.
The embossing and laminating unit according to one or more of the preceding claims, characterized in that said first protuberances on the first embossing roller and said second protuberances on the second embossing roller are arranged in sets so as to define mutually adjacent areas of a substantially quadrangular shape, in two adjacent areas on one and the same roller the protuberances being arranged in longitudinal directions different from one another, and the orientations of the longitudinal directions being such that in said nip the protuberances opposed to one another of two corresponding areas on the two rollers are inclined with respect to one another so that each protuberance of one area intersects a plurality of corresponding protuberances of the opposed area.
The embossing and laminating unit according to Claim 5, characterized in that said protuberances have a longitudinal development that is substantially the same as one of the dimensions of the respective area.
The embossing and laminating unit according to Claim 5 or 6, characterized in that said areas have a substantially square development.
The embossing and laminating unit according to Claim 5, 6 or 7, characterized in that said protuberances have a helical development.
The embossing and laminating unit according to one or more of Claims 5 to 8, characterized in that said areas are aligned according to helical alignments about the axis of the respective embossing roller, along a helical alignment the areas being arranged in such a way that the protuberances of two adjacent and consecutive areas on said alignment have longitudinal directions that are differently oriented.
The embossing and laminating unit according to one or more of Claims 5 to 9, characterized in that said protuberances have a variable cross section, minimum at the center and maximum at the end of each protuberance.
The embossing and laminating unit according to one or more of Claims 5 to 10, characterized in that interspersed between areas of elongated protuberances are areas containing protuberances that define decorative patterns, the areas containing protuberances that define decorative patterns of one roller correspond, in said nip between the two embossing rollers, to the areas containing protuberances that define decorative patterns of the opposed roller.
The embossing unit according to Claim 11, characterized in that said areas containing protuberances that define decorative patterns have a size that is a multiple, and preferably four times that, of the areas containing the elongated protuberances.
The embossing unit according to one or more of the preceding claims, characterized in that said protuberances have edges that are rounded in positions corresponding to their distal ends.
The embossing unit according to one or more of the preceding claims, characterized in that said protuberances have edges that are rounded in positions corresponding to their bases.
A multiply embossed paper-sheet material, comprising at least a first ply and at least a second ply, bonded to one another by gluing, in which said first ply and said second ply have first protuberances and second protuberances, oriented towards the inside of the weblike material, at least some of the first protuberances of the first ply corresponding to some of the second protuberances of the second ply, characterized in that at least some of said first and second protuberances are elongated in longitudinal directions that intersect one another so that protuberances that correspond to one another are in mutual contact and glued in an intermediate area of their longitudinal development.
The sheet material according to Claim 15, characterized in that said first and said second protuberances are arranged and configured in such a way that with a mutual staggering of the two plies they can come to arrange themselves according to a nested configuration, with the first protuberances of the first ply set between the second protuberances of the second ply.
The sheet material according to Claim 15 or 16, characterized in that said first protuberances and said second protuberances elongated in said longitudinal directions are arranged on the first ply and on the second ply according to alignments that are inclined with respect to the edges of the sheet and that intersect one another.
The sheet material according to one or more of Claims 15 to 17, characterized in that said first protuberances on the first ply and said second protuberances on the second ply are arranged in sets so as to define mutually adjacent areas of a substantially quadrangular shape, in two adjacent areas on one and the same ply the protuberances being arranged in longitudinal directions different from one another, and the orientations of the longitudinal directions being such that the protuberances opposed to one another of two corresponding areas on the two plies are inclined with respect to one another so that each protuberance of one area intersects a plurality of corresponding protuberances of the opposed area.
The sheet material according to Claim 18, characterized in that said protuberances have a longitudinal development that is substantially the same as one of the dimensions of the respective area.
The sheet material according to Claim 18 or 19, characterized in that said areas have a substantially square development.
The sheet material according to Claim 18 or 19 or 20, characterized in that said protuberances have a development that is inclined with respect to the edges of the sheet material.
The sheet material according to one or more of Claims 18 to 21, characterized in that said areas are aligned according to alignments that are inclined with respect to the edges of the sheet material, along one alignment the areas being arranged in such a way that the protuberances of two adjacent and consecutive areas on said alignment have longitudinal directions that are differently oriented.
The sheet material according to one or more of Claims 18 to 22, characterized in that said protuberances have a variable cross section, minimum at the center and maximum at the end of each protuberance.
The sheet material according to one or more of Claims 18 to 23, characterized in that interspersed between areas of elongated protuberances are areas containing protuberances that define decorative patterns, where the areas containing protuberances that define decorative patterns of one ply correspond to the areas containing protuberances that define decorative patterns of the other ply.
The sheet material according to Claim 24, characterized in that said areas containing protuberances that define decorative patterns have a size that is a multiple, and preferably four times that, of the areas containing the elongated protuberances.
The sheet material according to one or more of Claims 15 to 25, characterized in that said protuberances have edges that are rounded in positions corresponding to their ends that are internal to the weblike material.
The sheet material according to one or more of Claims 15 to 26, characterized in that said protuberances have edges that are rounded in positions corresponding to their ends that are more external to the weblike material.
The sheet material according to one or more of claims 15 to 27, characterized in that said first and second plies are made of tissue paper, with a weight per surface unit of each ply of between 12 and 30 g/m², said sheet material having preferably a total weight per surface unit of between 25 and 110 g/m².
An embossing and laminating unit for the production of an embossed weblike material comprising at least two plies embossed separately and bonded to one another, said unit comprising a first embossing roller with first embossing protuberances and a second embossing roller with second embossing protuberances, said embossing rollers defining a nip between them, said at least two embossed plies passing through said nip, characterized in that at least some of said first protuberances have a linear development and surround at least partially areas defined by depressed surface portions.
The embossing unit according to claim 19, characterized in that said first and second embossing rollers are mutually positioned such that said depressed surface portions are arranged in positions corresponding to which protuberances of the second roller come to insert, in correspondence of said nip.
The embossing unit according to Claim 29 or 30, characterized in that said areas are surrounded almost completely, except for limited interruptions, by said first protuberances.
The embossing unit according to Claim 31, characterized in that said interruptions have an extension equal to or less than 25% of the development of the perimeter surrounding said areas.
The embossing unit according to one or more of claims 29 to 32, characterized in that said linear protuberances have a width of between 0.3 and 3 mm and preferably between 0.5 and 2 mm.
The embossing unit according to one or more of Claims 29 to 33, characterized in that said linear protuberances have a length of between 5 and 50 mm and preferably 10 to 25 mm.
The embossing unit according to one or more of Claims 29 to 34, characterized in that said linear protuberances define internal areas with a perimeter having a development of between 10 and 100 mm.
The embossing unit according to one or more of Claims 29 to 35, characterized in that within said linear protuberances of the first embossing roller are arranged further, preferably elongated, protuberances.
The embossing unit according to one or more of Claims 29 to 36, characterized in that said linear protuberances have edges that are rounded in positions corresponding to their own bases.
The embossing unit according to one or more of Claims 29 to 37, characterized in that said linear protuberances have edges that are rounded in positions corresponding to their own distal ends.
The embossing unit according to one or more of Claims 29 to 38, characterized in that it comprises a glue-dispensing unit, which applies a glue on the first ply in areas corresponding to at least some of said linear protuberances.
A multiply embossed-paper sheet material, comprising at least a first ply and at least a second ply, bonded to one another by gluing, in which said first ply and said second ply have first protuberances and second protuberances respectively, oriented towards the inside of the weblike material, characterized in that said first protuberances have a linear development and at least partially surround areas of the first ply that form swellings projecting towards the outside of the sheet material.
The sheet material according to Claim 40, characterized in that protuberances of said second ply are arranged in positions corresponding to said swellings and form a resting surface for the portions of the first ply corresponding to said swellings in order to reduce the risk of squeezing of said swellings.
The weblike material according to Claim 40 or 41, characterized in that said areas are surrounded almost completely, except for limited interruptions, by said first protuberances.
The weblike material according to Claim 42, characterized in that said interruptions are equal to or less than 25% of the development of the perimeter surrounding said areas.
The weblike material according to one or more of Claims 40 to 43, characterized in that said linear protuberances have a width of between 0.3 and 3 mm, and preferably between 0.5 and 2 mm, and preferably a height of between 0.2 and 3 mm, and preferably between 0.5 and 1.5 mm.
The weblike material according to one or more of Claims 40 to 44, characterized in that said linear protuberances have a length of between 5 and 50 mm, and preferably 10 to 25 mm.
The weblike material according to one or more of Claims 40 to 45, characterized in that said linear protuberances define swellings on the weblike material with a perimeter having a development of between 10 and 100 mm.
The weblike material according to one or more of Claims 40 to 46, characterized in that arranged within said linear protuberances of the first ply are further, preferably elongated, protuberances.
The weblike material according to one or more of Claims 40 to 47, characterized in that said linear protuberances have rounded edges on the outside of the weblike material.
The weblike material according to one or more of Claims 40 to 48, characterized in that said linear protuberances have edges that are rounded in positions corresponding to their own ends internal to the weblike material.