PETRI, Stefano (Via di Tiglio 340, Fraz. Massa Macinaia, Capannori, I-55060, IT)
| CLAIMS 1) Method for making a web paper material constituted by more paper superimposed plies, comprising a step of embossing at least one paper ply (1) in a corresponding embossing station (G) and its coupling by means of gluing with a further paper ply (2) advancing towards the said embossing station (G) , characterized in that the said further paper ply (2) is glued in a corresponding gluing station (C) upstream of said embossing station (G) with respect to the advancing direction of said further paper ply (2) and in that the glue is applied to said further paper ply (2) ■ when it results and advances between a roller (RA) of the gluing station (C) which provides to distribute the glue onto a side of the further paper ply (2) and a further roller (60) which guides and supports the further paper ply (2), the said further roller (60) being spaced from the said embossing station (G) . 2) Method according to claim 1 characterized in that it comprises a step of embossing two paper plies (1, 3) between which the said further paper ply (2) is positioned. 3) Method according to claim 1 characterized in that the glue applied to said further paper ply (2) is coloured glue. 4) Method according to claim 1 characterized in that the glue is applied on predetermined areas of said further paper ply (2), said areas being of predetermined shape and position. 5) Method according to claim 1 characterized in that the embossing of said at least one paper ply (1) determines the formation of micro-reliefs on the surface of the at least one embossed paper ply, further differently shaped reliefs being superimposed to the said micro-riliefs. 6) Method according to claim 5 characterized in that the said micro-reliefs are of pyramidal shape. 7) Method according to claim 5 characterized in that the said further reliefs are segment-shaped. 8) Method according to claim 1 characterized in that the said further paper ply (2) is embossed before the glue is applied on it. 9) Method according to claim 1 characterized in that the said further paper ply (2) is smooth, that is, not embossed. 10) Device for embossing and coupling by gluing two or more paper plies or webs (1, 2, 3) which, once embossed and glued form a multi-layer web material, wherein each of the said paper plies (1, 2, 3) constitutes a corresponding layer of the finished product, device comprising a first operative station (C) with at least a gluing unit (4; 40) and a second operative station (G) with at least an embossing unit (5; 50), characterized in that the said first operative station (C) is located upstream of said second operative station (G) with respect to an advancing direction of a paper ply (2) advancing towards the first operative station (C) , where it is glued, and is directed towards the second operative station (C) following a path (T) which separates the said first and second operative stations (C, G) . 11) Device according to claim 10 characterized in that two gluing units (4, 40) are provided or activated or utilized in the said gluing station (C) . 12) Device according to claim 10 characterized in that two embossing units (5, 50) are provided in the said embossing station (G) . 13) Device according to claim 10 characterized in that the said at least one gluing unit comprises a tank containing coloured glue and a gluing roller (RA) which applies the glue by contact to the paper ply (2) to be glued, the said gluing roller (RA) being provided with reliefs on its external surface. 14) Device according to claim 10 characterized in that an embossing unit comprises an engraved roller (RI) provided with micro-riliefs (RP) and further differently shaped reliefs (RR) . |
Method and device for the production of embossed web material.
DESCRIPTION The present invention relates to a method and a device for the production of embossed web material, particularly of the type comprising two or more glued paper plies. It is known that in the production of items such as paper towels, toilet paper, paper napkins and the like, a paper web material is subjected to embossing to increase its apparent thickness, in order to improve the characteristics of absorption and also for aesthetic reasons. In general, the web material is made up of two or more plies of paper which are embossed and then joined by gluing. The embossing is done by means of units including embossing cylinders fitted with metal spikes which provoke corresponding effects on a paper web travelling at a preset speed. The glueing is performed by groups including a tank for the glue and a series of rollers that remove the glue from the tank and distribute the glue on the web subjected to embossing.
The embossing provokes the breaking of the paper fibers and consequently the production of paper dust. Therefore, on the rollers of the glueing groups as well as in the respective tanks there is the formation of pastes whose effects on the functioning of the system are strongly negative. Accordingly, the glueing groups must be subjected to frequent cleaning and maintenance and it is necessary to provide for use constant and intensive filtration of the glue. This is inconsistent with the current production requirements, since the cleaning maintenance and filtration operations are expensive, skilled personnel is required and such operations can lead to long stops of the production lines. One aim of the present invention is to reduce the above-mentioned drawbacks. Another objective of the present invention is to propose a method and a device for distributing glue on paper webs in a manner which permits the achievement of particular aesthetic or decorative effects while the glueing is executed. This result has been achieved, according to the present invention, by adopting the idea to realize a device and a method having the characteristics described in the independent claims. Further characteristics of the present invention are the object of the dependent claims. Thanks to the present invention, the glueing groups are much less affected by the formation of paste previously mentioned, which require less frequent maintenance and less intensive filtering of the glue. Furthermore, the present invention makes it possible to produce paper webs consisting of multiple overlapping paper plies on which special decorative effects are visible. These and further features and advantages of the present invention will be better understood by anyone skilled in the art from a reading of the following description in conjunction with the attached drawings, given as a practical exemplification of the invention but not to be considered in a limitative sense, wherein: - Fig. IA schematically represents a device in accordance with the present invention, in which three plies of paper are worked, with two embossing units featuring embossers with pyramid engravings and two glueing units which are both active;
Fig. IB is a schematic top view of a paper web material leaving the device shown in Fig. IA; Fig.2A schematically represents a device as in Fig.l, where, however, only one glueing unit is active;
Fig.2B is a schematic top view of a paper web material leaving the device shown in Fig.2A; Fig.3 schematically represents a device as in Fig.l, wherein two paper plies are worked and only one glueing unit is active;
Fig.4 represents a schematic perspective view of an applicator roller (RA) of a glueing unit according to a possible execution form; Fig.5 schematically represents an engraved roller (RI) according to possible execution form;
Figs. 6 and 7 schematically represent further effects visible on the product leaving a device in accordance with the present invention;
Fig.8 represents a scheme concerning a further example of use of the present invention. A device according to the present invention can be used for embossing and bonding of two or more plies or ribbons of paper (1, 2, 3) which, when embossing and bonding are executed, constitute a multilayer web material in which each of the said plies (1, 2, 3) represents a corresponding layer of the finished product. The latter can be used to make, for example, paper towels, toilet paper and similar products.
Reduced to its essential structure and with reference to the figures of the attached drawings, a device in accordance with the present invention includes a first operating station (C) with at least one glueing or sizing unit and a second operating station (G) with at least one embossing unit, in which a 1 paper ply advances between the first station (C) and the second station (G) along a path that separates these stations, and in which the said first station (C) is upstream of the second station (G) with respect to the paper advancing direction. In the glueing or sizing station (C) may be present, or active or used, one or two glueing units (4, 40) .
The glueing units (4, 40) are of the known type, i.e. of the type comprising a tank (S) containing glue, a roller (RA) which applies the glue on the paper plies coming into contact with it, and a distributor roller (RD) , which is located between the tank (S) and the applicator roller (RA) and removes the glue from the tank and distributes it to, by contact, on the surface of the applicator roller.
The said units (4, 40) are superimposed, to form an upper glueing unit (4) and a lower glueing unit . Similarly, in the embossing station (G) may be present, or active or used, one or two embossing units (5, 50) .
The embossing units (5, 50) are also of the known type, i.e. of the type comprising a roller (RE) with an elastic outer surface and a roller (RI) with a rigid engraved outer surface arranged to form a nip through which a paper ply can pass so that, as a result of its transit between the rollers (IR, IR) it is correspondingly embossed.
The said embossing units (5, 50) are arranged so that the respective engraved rollers (RI) are superimposed, to form a nip through which two or more paper plies can pass. With reference to all the examples that follow, the roller (RA) and (RD) as the cylinders (RE) and (RI) are horizontal, i.e. they are are oriented transversely to the direction followed by the paper plies inside the device. With reference to the example shown in Fig.l, the glueing station (C) comprises two glueing units (4, 40) and the embossing station (G) consists of two embossing units (5, 50) which are superimposed. All the units (4, 40, 5, 50) are in use. The plies of paper (1, 2, 3) being treated three in number. A first ply (1) is embossed by the first embossing unit (5), a second ply (2) is glued, passing on the final roller (RA) of both the glueing units (4, 40), and a third ply ( 3) is embossed by the other embossing unit (50). The arrows "Fl", "F2" and "F3" indicate the advancing direction of the paper plies (1, 2, 3) . The second ply (2) is driven by a series of driving rollers (6, 60) and is thus forced to follow a path that brings it at the glueing station (C) where the same ply comes into contact with the applicator rollers (RA) of both units (4) and (40) . The said driving rollers (6, 60) are oriented parallel to the above mentioned roller (RA, RD) and cylinders (RE, RI) and on the last of them, which is indicated by the numeral reference (60) in the drawings, the ply (2) is driven while it is in contact with the applicator rollers (RA) of the glueing station (C) . In other words, while the ply (2) is glue by virtue of its contact with the rollers (RA) , it is simultaneously driven by the driving roller (60) . The latter is positioned at a predetermined distance from the embossing station (G) so that, once glued, the ply (2) advances along a path (T) of predetermined length that separates the glueing station (C) from the embossing station ( G) . The normal advancing speed of the paper plies and the normal composition of the glue contained in the tanks (S) are such that during the transit from the glueing station (C) to the embossing station (G) the glue applied to the ply (2) does not dry. In practice, the first ply (1) is embossed by the embossing unit (5), while the second ply (2) is sized by passing on the applicator rollers (RA) , first on the applicator roller of the lower unit (40) and then on the applicator roller of the upper unit (4 ) , and the third ply is embossed by the embossing (50) . Subsequently, the glued ply (2) and the embossed plies (1, 3) pass all in the nip between the engraved rollers (RI) and then in another nip, formed by the engraved roller (RI) of the upper embossing unit (5) and a pressure roller (7) . Therefore, it is formed a web (8) with three overlapping plies in which the two outer plies (1, 3) are embossed and the intermediate ply (2) determines a bonding effect due to the glue previously applied on it. The bonding occurs as a result of the pressure exerted by the pressure roller (7) on the paper plies leaving the station (G) . For "glueing" it is meant the distribution of adhesive on one side of a paper ply (in the example, the paper ply marked by the reference number "2") .
Since the ply (2) is glued before passing between the engraved rollers of the embossing station, on the surface of the applicator rollers (RA) of the glueing units neither paper powder nor paper fibers can deposit as, on the contrary, occurs in devices that provide for the distribution of the glue on the surface of the engraved rollers or on already embossed plies. Therefore, it is preserved the structural and functional integrity of the glueing units and, therefore, less frequent maintenance interventions are required.
The said applicator rollers (RA) may be provided with reliefs or "stamps" (eg reliefs "F" having the shape of a leaf as in the attached drawings) and the glue contained in the tanks (S) can be colored.
The reliefs of the roller (RA) can be differentiated so that the roller (RA) of the upper glueing unit (4) can be differently shaped or sized compared to the those of the roller (RA) of the lower glueing unit (40) . In this case, as shown in Fig. IB, on the finished product it is possible to see the effect (EG) of the embossing (eg pyramidal reliefs if the engraved rollers RI are provided with reliefs having such a shape) , the color (CT) tvisible through the outer or upper ply (1) of the web (8), and the color (CP) that as a result of the pressure exerted by the roller (7) emerges on said outer or upper ply (1) and highlights, in particular, the reliefs due to the embossing. With reference to the example shown in Fig.2, unlike the previous case, the central or intermediate ply (2) passes on one glueing unit (4) only. The remaining operating sequence is identical to that described for the previous case. The effect is shown schematically in Fig.2B. In this case, as the ply (2) passes only in correspondence of the glueing unit (4) and not of the glueing unit (40), the overall effect is different: on the portion of the web (8) shown in Fig.2B only one leaf is visible (it is due to the reliefs of the roller RA of the unit 4) . The diagram shown in Fig.3 is the same as that of Fig.2 but, in this case, the finished product (8) is a web formed by two plies (1, 2) . The overall visible effect on the upper ply (1) of the finished product is identical to that shown in Fig.2B.
One of the engraved rollers (RI) may be provided with further reliefs (RR) , in addition to the reliefs or micro-relief (for example pyramidal reliefs RP as previously mentioned) that are normally provided to execute the embossing. For example, the said further releiefs (RR) may have the shape of irregular segments, as shown schematically in Fig.5. In this case, as shown in
Figg. 6 and 7, on the upper ply (1) of the product (8) leaving the device further effects may be observed, due to such further reliefs
(RR) . In accordance with the present invention, the treatment of paper plies to be overlapped and joined together by glueing provides, therefore, a step of sizing or glueing a paper ply performed in a sizing or glueing station (C) placed at a predetermined distance from an embossing station
(G) in which the embossing of at least another paper ply takes place. In other words, the said glueing step is not executed at the embossing station as happens in conventional devices, in which an applicator roller of a glueing unit acts directly on a paper ply which, while the glueing takes place, is close to an engraved roll of an embossing unit. In accordance with the present invention, the glue is applied on the paper ply while this is far from an engraved roll of an embossing unit (ie on a not embossed ply with reference to examples of Figs. IA, 2A and 3, where the not embossed ply is marked by the reference number "2") . However, the present device can also be used as shown in Fig.8 if desired: the paper ply (2) subjected to glueing in the glueing station (C) is a ply that has been embossed. In this case, the ply (2) carries a certain amount of paper powder due to its embossing but to a lesser extent than the quantity produced at the corresponding embossing station (G2) and by virtue of the fact that along the path between the station (G2) and the station (C) a part of the powder determined by embossing disperses.
As is apparent from the above description, the glue can be colored and can be applied on a paper ply (embossed or smooth, that is embossed or not embossed) forming glueing areas having a predetermined shape (corresponding to the shape of the reliefs or "stamps" F of the applicator rollers RA) and can be applied in a single step
(for example, as mentioned above, using one glueing or sizing unit) or in two steps (using two glueing units arranged along a path followed by the ply to be glued so that the glueing is performed in sequence by the two glueing units) .
Furthermore, as can be seen from the above, the embossing step can be performed using an engraved roller (RI) provided with additional reliefs
(RR) , in addition to micro-relief or reliefs (eg the pyramid reliefs RP mentioned above) used to perform the very embossing. The glueing of the paper ply (2) is executed when it is located and passes between a roller (RA) of the glueing station (C) and a driving smooth roller (60) that supports the ply (2) while the latter is being glued and that is physically separates from the rollers (RI, RE) of the embossing station (s). In other words, the said driving roller (60) is away from the embossing station (s) (G) .
The said glueing or siziong units (4, 40) may apply glue of the same color on the ply (2) or glue of different colors, with the unit (4) applying glue of a color and with the unit (40) that applies glue of another color.
Practically, the construction details may vary in any equivalent way as far as the shape, dimensions, elements disposition, nature of the used materials are concerned, without nevertheless departing from the scope of the adopted solution idea and, thereby, remaining within the limits of the protection granted to the present patent.
Next Patent: DEVICE AND METHOD FOR COUPLING TWO OR MORE PAPER WEBS OR PLIES BY GLUING.