Embossed paper multi-ply material

IS 2 365 452 T3

DESCRIPTION

Multilayer embossed paper material and machine for its production

Technique field

The present invention relates to improvements in multilayer materials made of paper, in particular of so-called tissue paper, for example, for the production of absorbent products, toilet paper, kitchen towels and the like.

State of the art

In the field of tissue paper transformation and manufacturing it is well known to produce multilayer products, in which two or more embossed layers of tissue paper are joined together by lamination and gluing according to different techniques.

For example, US-A-3961119 describes a two-layer material, in which the two layers are separately embossed with helical configurations with different inclinations and coupled at the intersection of the helical configurations.

US-A-6470945 describes a machine for embossing layers which, once joined together, form a continuous web material with layers coupled end to end or chained respectively. The end-to-end joint is provided a joint, in which the protrusions of one layer are at least partially in correspondence with the protrusions of the other layer. Vice versa, the chained joint is provided a joint, in which the protrusions of one layer are chained between the protrusions of the other layer.

Other embossed multilayer products and devices for producing these are described and illustrated, for example, in patents US-A-6261666, US-A-6109326, US-A-2003/0102096, US-A-6136413, WO -A-00/78533, USA-6681826, US-A-3414459, US-A-5173351, US-A-6032712, US-A-6245414, WO 99/44814.

US-A-4,320,162 describes a multilayer product with two layers embossed with the same embossing on both sides, that is, on both layers. The embossments are arranged end to end and are made up of large protrusions with a large front surface, between which protrusions with a smaller height and smaller dimension are arranged.

Embossed multilayer materials must satisfy a plurality of requirements that often contrast with each other, such as in particular: softness, absorption capacity, thickness, mechanical resistance also when soaked with a liquid, ability to remove materials from cleaned surfaces using embossed paper , and also other requirements.

There is a constant search to identify techniques for embossing, laminating and bonding layers, which allow to optimize the performance of these materials from many points of view, which are also mutually contrasting. Summary of the invention

According to one aspect, an object of the present invention is to provide a multilayer paper web material, in particular formed by a plurality of layers of a material made of embossed tissue paper, which presents improved characteristics with respect to traditional products. , at least one or some aspects.

According to one embodiment, the multilayer material made of embossed tissue paper according to the present invention comprises at least one first outer layer and at least one second outer layer joined to the other in correspondence with first protrusions obtained on one and on the other of said layered and facing inward. The joint is of the end-to-end type, that is, a joint in which the protrusions obtained in a first layer are in correspondence with the protrusions obtained in the other layer. Preferably, between the two outer layers two inner layers are arranged, one or both of which are preferably embossed. Contrary to traditional end-to-end products, according to the present invention (in addition to a first series of protrusions joined end-to-end obtained both in the first and second outer layer, and which have a linear development to form configurations decorative with a large surface extension) each of the two outer layers also provides a second series of bumps, also oriented towards the inside and defining a background pattern, which is preferably constituted by a plurality of protrusions with a simple geometric shape, for example, and in particular truncated or frustoconical pyramidal shapes.

The layers are joined together by gluing and lamination in correspondence of at least the protrusions with linear development of the first and second layers.

IS 2 365 452 T3

According to an advantageous embodiment, the protrusions with truncated pyramids, frustoconical or however with a simple geometric shape, which define the bottom embossing, have a front surface of the protrusions equal to or less than 4 mm².

Preferably, the bottom bumps have a density between 2 and 25 and more preferably between 3 and 8 bumps / cm².

According to some advantageous embodiments, the first embossing protrusions or at least some of them, both in the first and in the second outer layer, preferably define closed lines, within which areas or sections of the respective layers are delimited, devoid of or substantially devoid of embossing, that is, smooth areas. Preferably, these areas form swellings that are oriented outward of the multilayer material.

Preferably, according to some embodiments, at least the third layer and preferably both the third inner layer and the fourth inner layer of the multilayer material are embossed.

The embossments obtained on the third and / or on the fourth inner layer are formed by protrusions facing outwards, that is to say, facing respectively the first and second outer layers of the multilayer material.

In order to obtain a product with a greater thickness, which does not tend to press or sink during packaging, for example during roll winding, the geometric protrusions of the third layer and of the fourth layer arranged inside the first outer layer and the second outer layer are preferably arranged, at least in some of the areas or areas devoid of embossing delimited by the protrusions of linear embossing of the first layer and of the second layer, so that they support these areas devoid of embossing and keep them swollen and extend towards the outside of the multilayer material.

In this way, a particular soft material is obtained with a large apparent thickness and with a highly aesthetic appearance, thanks to the wide embossing configuration delimited by the protrusions with linear development of the two outer layers. The thickness of the material is also maintained when the material is rolled, for example, to form kitchen paper rolls, thanks to the presence of the geometric protrusions of the two inner layers that are arranged within the non-embossed areas delimited by the protrusions linear lines of the two outer layers, that is, they are chained between said linear protrusions.

Other advantageous characteristics and embodiments of a multilayer material according to the present invention are set forth in the appended claims and will be described in greater detail with reference to some non-limiting embodiments of the invention.

According to another aspect, the invention also relates to an embossing machine or unit for the production of a web material as defined above.

Basically, in an embodiment of the invention the machine comprises a first embossing roller and a second embossing roller, which cooperate with a respective first pressure roller and a second pressure roller and each one of them provided with first protrusions with linear development , the first protrusions of the first and second rollers being arranged in an end-to-end arrangement. Each of the first and second embossing rolls comprises second protrusions defining a background pattern.

Brief description of the drawings

The invention will be better understood from the following description and the accompanying drawings, which show non-limiting practical embodiments of the invention. More particularly, with reference to the accompanying drawings:

Figure 1 shows a plan view of a length of a web material according to the present invention;

Figure 2 shows a highly enlarged schematic section according to the line II-II of Figure 1; Figure 3 shows a schematic of an embossing machine or unit for the production of a web material of the type illustrated in Figures 1 and 2.

Detailed description of embodiments of the invention

Figure 1 shows a top view of a section of a multilayer material according to the present invention, indicated as a set with the number 1. Figure 2 shows a schematized and widely enlarged cross section, according to the line II-II from figure 1, of material 1, from which it is evident that the material is made up of four layers and precisely: a first outer layer V1, a second outer layer

V2, a third inner layer V3 arranged between layers V1 and V2, and a fourth inner layer V4, also arranged between layers V1 and V2. More precisely, the V3 layer is arranged between the V1 and V4 layer, and the V4 layer is

ES 2 365 452 T3 arranged between layer V3 and layer V2.

According to an advantageous embodiment, the outer layers V1 and V2 are embossed with an end-to-end configuration, that is, in such a way that the protrusions of the layer V1 have the same or substantially the same shape as the protrusions of the layer V2 and correspond to each other, with an arrangement in which the front surfaces of the protrusions of one layer correspond to the front surfaces of the like-shaped protrusions of the other layer.

According to an advantageous embodiment, both on layer V1 and on layer V2 first protrusions are provided, indicated respectively with the number 5 and 7 for layers V1 and V2, which present a linear development, that is, an extension of greater dimension in relation to the transversal dimension. In some embodiments each protrusion 5, 7 has a length at least 10 and preferably 20 times and more preferably 50 times greater than the transverse dimension in width of the protrusion itself.

According to some preferred embodiments, the protrusions 5 and the corresponding protrusions 7 or at least some of them have a closed shape, that is, said shape defines areas, indicated with the letter A in figure 1, which are completely or practically completely enveloped by respective linear protrusions 5, 7. In some embodiments, the areas A thus delimited are devoid of embossing, that is to say, they are substantially smooth, that is to say, devoid of protrusions. These are preferably swollen, that is, they protrude out of the multilayer material 1, forming a type of protrusions, bubbles or swellings, while the protrusions 5 and 7 are oriented towards the interior of the multilayer material 1.

In addition to the linear protrusions or protrusions 5, 7, each layer V1, V2 has additional protrusions 9, 11, which are also arranged in a preferably end-to-end configuration and, as shown in figure 1, with a geometric shape simple. In some embodiments, the protrusions 9, 11, which are oriented again towards the interior of the multilayer material 1, have frusto-pyramidal or frusto-conical shapes, with a front surface preferably less than 4 mm².

In some embodiments, as shown in Figures 1 and 2, the inner layers V3 and V4 are provided with respective outward-facing protrusions 13, 15, that is, the protrusions 13 provided in the layer V3 facing the layer. outer layer V1 and the protrusions 15 provided in the layer V4 facing the outer layer V2. In some embodiments, the protrusions of the layers V3 and V4 have variable heights, as shown for example in the embodiment of figure 2. In this case, protrusions or protrusions 13 and protrusions 13X are provided on the layer V3, with respective height H and h, and on the layer V4 protrusions 15X and 15 with the height H and h are arranged.

In some embodiments, a plurality of protrusions 13 of layer V3 and protrusions 15 of layer V4 are arranged in correspondence with areas A of layers V1 and V2 delimited by linear protrusions 5, 7. In this way, the swellings formed in the zones or areas A delimited by the linear protrusions 5, 7 are supported by the protrusions 13, 15 formed by the inner layers V3, V4 and facing outwards, arranged in a chained arrangement within linear protrusions 5, 7. This facilitates the maintenance of the entire thickness, indicated by the letter S, of the multilayer material 1 also if the latter is rolled up to form, for example, a roll of kitchen paper, bathroom paper or the like.

To simplify the drawings, in figure 2 the protrusions 13X are shown only at the right angle to the base, where the layer V1 is raised so as to show the embossed structure underneath. Vice versa, in the smooth areas A surrounded by the protrusions 5, the protrusions 13 of the layer below are shown with a broken line, so as to show how they are arranged to support the layer sections in the areas A devoid of embossing.

The protrusions 13X, 15X may have a lower height than the protrusions 13, 15, as shown in Figure 1, since they do not have to perform a specific support function. However, it is possible that the protrusions or protrusions 13X, 15X have a height equal to the height H of the protrusions 13, 15.

Finally, with a configuration of this type, it is possible to obtain a material with great thickness and very soft, that is resistant to compression or subsidence, with highly detergent characteristics thanks to the presence of protuberances 5, 7 with linear development that define, on the outer surface of the layered material 1, linear cavities to collect impurities, such as, for example, dust, liquid or others, collected from the surfaces that are cleaned with the material 1.

Advantageously, the layers V1 and V2 are glued to each other by lamination in correspondence with the protrusions 5, 7, and 9, 11, in an end-to-end arrangement, all of these protrusions having the same height or at least the protrusions 5, 9 having the same height and similarly the protrusions 7, 11 having the same height. In a modified embodiment, the height of the protrusions 9, 11 may be different, and in particular, less than the height of the protrusions 5, 7.

IS 2 365 452 T3

The protrusions 13, 15 can be distributed with a variable density, for example, the protrusions 13, 15 with a density greater than that of the protrusions 13X, 15X, so that it forms a more effective support for the swollen areas A.

In some embodiments, the protrusions 13, 15 and / or the protrusions 13X, 15X may have a density between 5 and 10 protrusions / cm².

The dimensions of the protrusions 13, 15 and 13X, 15X may be such as to define surface areas on the upper ends (i.e., facing outward) of the protrusions equal to or less than 4 mm.².

A multilayer material 1 of the type described above can be obtained for example with an embossing machine or unit of the type represented schematically in Figure 3 and indicated as a set with the number

twenty. In some embodiments, the embossing unit comprises a first embossing roll 21 and a second embossing roll 23 provided with mirror-like engravings so that they emboss in an end-to-end arrangement and laminate the first outer layer V1 with the second outer layer. V2 of multilayer web material 1.

The surface configuration of the rollers 21 and 23 substantially reproduces the shape of the protrusions 5, 9 for one of the rollers and 7, 11 for the other roller.

The embossing rollers 21 and 23 cooperate with respective pressure rollers 25, 27, for example, coated by rubber or other material with elastic deformation so that they emboss separately from each other the layers V1 and V2 supplied along the respective feed paths around pressure rollers 25, 27 and in the groove between rollers 25, 21 and 27, 23 respectively.

Between the embossing rollers 21 and 23 a lamination groove 29 is defined, through which the embossed layers V1, V2 pass and in correspondence of which said layers are mutually laminated by gluing them thanks to the glue applied by one or the other of the two glue dispensing units 31, 33.

In addition to the pairs of pressure and embossing rollers 21, 25 and 23, 27, the embossing unit 20 comprises a third additional embossing roller 35 and a fourth embossing roller 37, cooperating respectively with a third pressure roller 39 and a fourth pressure roller 41, covered with a material with elastic deformation, such as rubber or others.

The third layer V3 and the fourth layer V4 are supplied along respective paths by the embossing unit 20, and are separately embossed in the grooves respectively defined between the pressure roll 39 and the embossing roll 35 and between the pressure roller 41 and pressure roller 37. The embossing rollers 35, 37 are engraved with protrusions corresponding to the protrusions 13, 13X and 15, 15X generated by the rollers in the inner layers V3 and V4. As shown in the diagram of figure 3, the arrangement of the rollers is such that the protrusions of the rollers 35 and 37 generate corresponding protrusions in the layers V3 and V4 oriented towards the layers V1 and V2 in the groove between the pairs of the rollers 21, 35 and 23, 27. In this way the protrusions 13, 13X generated by the embossing roll 35 and the protrusions 15, 15X generated by the embossing roll 37 are oriented towards the outside of the multilayer material 1.

The arrangement of two glue dispensing units 31, 33 makes it possible to apply the glue on the protrusions 5, 9 obtained on the layer V1 by means of the dispensing unit 31 and on the protrusions 7, 11 generated on the layer V2 by the embossing roller 23 by means of the glue dispensing unit 33, so that it has a sufficient quantity of glue to roll-engage in the groove 29 the four layers V1, V2, V3 and V4 to each other.

It is understood that the drawings only show an example provided by way of a practical arrangement of the present invention, which may vary in shapes and arrangements without thereby departing from the scope of the concept of the invention.