EP4650162A1

EP4650162A1 - Assembly for the progressive embossing of sheets of paper

Info

Publication number: EP4650162A1
Application number: EP23915216.8A
Authority: EP
Inventors: Tsutama Satake Neto
Original assignee: Valmet Engraving Solutions Ltda
Current assignee: Valmet Engraving Solutions Ltda
Priority date: 2023-01-11
Filing date: 2023-01-11
Publication date: 2025-11-19
Also published as: WO2024148407A1

Abstract

Comprising an integrated module (5) to generate a progressive embossing (on the same embossing elements) of at least two continuous strips of paper, traditionally known as "tissue paper" which, after being juxtaposed, form a continuous strip of bulky and soft paper for the manufacture of toilet paper.

Description

Field of Invention.

More particularly, this Invention refers to technical and functional improvements specially created to generate a progressive embossing (on the same embossing elements) of at least two continuous strips of paper, traditionally known as "tissue paper", which, after being juxtaposed, form a continuous strip of bulky and soft paper for the manufacture of toilet paper.

State of the art.

As is well known, embossing is currently a widely used technique to change the texture, feel, volume and appearance of certain paper products supplied in rolls or sheets, such as toilet paper, paper towels, paper tissues, paper napkins and others. All of them can be produced with just one layer or with two or more layers. Each layer undergoes a embossing process that, in short, could be said to be a process similar to that of stamping, where the mechanical means used exert pressure on the smooth surface of the material, causing it a plurality of deformations in high and low relief that, combine with each other to define a embossing pattern, from the simplest defined by geometric details, to the most elaborate ones that form true art drawings. Thus, the technology of embossing paper turned out to be an efficient resource to change the characteristics of a sheet of paper, especially when it is formed by two or more layers, adding important advantages, that is, initially, embossing changes the texture of the paper, making it very soft and delicate, which favors a pleasant touch. In the same way, by changing the texture, the volume is also substantially changed to greater, that is, the paper no longer has that smooth appearance and "compact" effect and starts to have a "lighter and fluffier" appearance, with the same amount of paper. As far as appearance is concerned, embossing undoubtedly defines decorated surfaces on both sides of the paper. Logically, the "imprint" adopted for embossing allows a variety of combinations of reliefs that compete to obtain all sorts of designs, which significantly improves the look of the paper, even suggesting its good quality and origin, adding more resources to establish the product's brand with the final consumer.
Currently, different equipment for embossing paper are known, all of them combine a series of engraved and unengraved cylinders, some metallic and others rubber, however, regardless of such aspects, each machine has its own particularities inherent to the final product, as taught in the documents listed below:

BR102012008803 - published on 4/15/2014
CYLINDER ENHANCEMENT FOR TISSUE PAPER LAMINATION
BR102012025250 - Published on 4/19/2016
IMPROVEMENT IN EMBOSSING CYLINDERS FOR TISSUE PAPER LAMINATION
BR102013026900 - published on 8/25/2015
EMBOSSING ASSEMBLY FOR PAPER PROCESSING
BR112020022071 - Published on 2/2/2021
JOINT EMBOSSING IMPROVEMENT FOR PAPER PROCESSING
US3556907 - published on 1/19/1969
EMBOSSED LAMINATED PAPER MAKING MACHINE
US6245414 - Published on 6/12/2001
EMBOSSING AND LAMINATING MACHINE FOR GLUING EMBOSSED LAYERS
US5382464 - published on 1/17/1995
MULTI-LAYER EMBOSSED PAPER AND MANUFACTURING METHOD AND APPARATUS
EP2674505 - published on 12/18/2013
MANUFACTURING METHOD OF ROTOGRAVURE ROLLER AND ROTOGRAVURE ROLLER
WO2018229676 - published on 12/20/2018
DEVICE FOR MICRO-STAPLE OF PAPER AND PAPER PROCESSING LINE COMPRISING SAID DEVICE
EP0370972 - published on 5/30/1990
PAPER ENGRAVING MACHINE
BRPI0512124A - published on 2/6/2008

Therefore, tissue paper, due to its peculiar characteristics, is widely used in different products, notably toilet paper, paper towels and napkin paper, however, to enrich the quality of such products, they undergo an embossing process that, traditionally, can vary according to the product to be obtained.
Thus, the process of embossing (plastering) tissue papers has as its main objective the construction of reliefs on the surface of the tissue paper, generally to increase thickness, softness and/or for aesthetic purposes.
Currently there are three processes for embossing: steel/rubber, steel/steel (with variations) and steel/paper. The basic characteristics of these three technologies are generically illustrated in figures 1, 2, and 3, where the "jagged shape of cylinders is only an example of the area where they are engraved". Because such engraving, as already mentioned, varies significantly according to the criteria of each toilet paper manufacturer.
The steel/rubber process is schematically illustrated in figure 1, where it is verified that the tissue paper (1A), with at least one layer, passes between an embossed steel roll (2) and a rubber roll (3), where the pressure between them causes the engraving (4) to be pressed against the surface of the tissue paper (1A) forcing it against the rubberized surface of the roll (3), consequently, the embossing (4) is transferred to the tissue paper (1A) by a process of deformation of the contact points/elements. In this way, two or more continuous strips of tissue paper (1A) and (1N) are combined in an assembly (5) herein called integrated module, because it integrates two sets of steel/rubber embossing, where at least one layer receives glue and the layers are juxtaposed, forming a finished continuous strip for the manufacture of toilet paper or paper towel rolls.
The steel/steel process (with variations) is schematically illustrated in figure 2, where it can be seen that the tissue paper (1A) passes between two rolls of embossed steel (2), where the engravings (4) are of the male and female type. In this process, the sheets of paper are formed, as there is a space between the elements of the embossing rollers. In the same way, the continuous strip of tissue paper produced may or may not be combined with other similar ones to form a continuous plastered strip, depending only on the final characteristics of the product (toilet paper, napkins, tissues, interfolded towels, and others).
The steel/paper process is illustrated schematically in Figure 3, where it can be seen that the tissue paper (1A) passes between an embossed steel roll (2) and a smooth paper coated roll (6) (smooth roll over a steel roll embossing process), as soon as the paper roll embossing process (7) is finished, the paper embossing process can be carried out, thus producing a continuous strip of embossed paper (1A) and, in the same way, this continuous strip of tissue paper produced can be combined with similar ones to form a continuous plastered strip used for the manufacture of toilet paper.
Figure 4 shows a complete integrated tissue embossing station or module. In this figure the usual process is defined to process two or more continuous strips of tissue paper (1A) and (1N), which pass equally between steel (2) and Rubber (3) rolls, between which each strip is embossed. In at least one of the steel rolls (2), glue applicator rolls (8) act against the corresponding surface of one of the tissue paper strips, in this case strip (1A). The two steel rollers (2) work adjacently and guide the continuous strips of tissue paper (1A) and (1N) so that they are juxtaposed, which happens in conjunction with a probe roller or pressing roller (9) which has the function of joining the sheets, after which a continuous embossed strip of tissue paper with two or more layers is formed and later used to manufacture paper rolls toilet or paper towel.
Figures 5A to 5C show schematically that, regardless of the embossing unit number, the concept of embossing is the same and is generally limited to the process with steel roller (2) and rubber roller (3). In figure 5A there are two embossing points. In figure 5B there are three embossing points. In figure 5C there are 4 embossing points.
On the other hand, as shown in figures 6A to 6C, although the embossing process is usually carried out with steel/rubber, steel/steel and steel/paper rolls, embossed tissue paper strips can be combined in different ways, among which the following stand out: combination (DERL), combination (DESL) and combination (PTP).
Figure 6A shows the combination (DERL), "double embossing randomic laminated", where the layers are joined by the pressing roller (9) and there is no overlapping synchronization (roller/sheet), that is, there is no synchronization of the engraved areas.
Figure 6B shows the combination (DESL), "double embossing synchronized laminated", where the layers are synchronized when overlapped and, in this case, male/female synchronism occurs with bonding by a pressing roller (9).
Figure 6C shows the combination (PTP), where the layers are synchronized when overlapped and, in this case, "point-to-point" synchronization occurs with compression joining between the steel rollers.
Figure (7A) shows the combination (DERL). Figure (7B) shows the point-by-point combination (PTP). Figure (7C) shows the combination (DESL).
Still referring to figures 7A - 7C, in the current embossing units with adhesive lamination system, the paper embossing process is done with the steel/rubber process.
In steel/rubber embossing processes, the thickness (deformation) of the paper will generally be less than the level of penetration of the embossing elements into the rubber due to the resilience of paper when leaving the embossing zone.
Generally, the level of penetration into the rubber is limited mainly by the characteristics for deformation/resilience of the rubber and in the background by the type of pattern/design of the embossing and the requirements of the completed/finished product.

So, as shown in the figures above, we have:

X and Y=	rubber penetration
P1/P2=	engraving depth
P1/P2	same or different
X and Y	less than P1/P2
X = Y
X > Y
X < Y
A and B	final paper deformation
A	less than X
B	less than Y

Objects of the Invention.

The main object of this Invention is technical and functional improvements of the technology (DESL), maintaining the same concept/stages of the conventional process (DESL), however, adding an additional stage so that the embossing process of the strips is done progressively with the concept of embossing steel/steel in sequence, where the continuous strips of upper and lower tissue paper are re-embossed in sequence and simultaneously, characterizing a progressive complementary stage. In this case we will have at least three stages of embossing in the same integrated module, that is, an upper embossing and a lower embossing, both steel/rubber, and then a third stage of progressive embossing with between the steel rollers (2) in the steel/steel concept. In this way, the embossing or deformation process of the strips begins in the first and second stages with the steel/rubber concept and the deformation is increased in the third stage with the steel/steel concept in a progressive way, completing the previous stages, producing advantageous effects, that is, higher levels of penetration that result in greater thicknesses in the tissue paper strip, consequently, embossing effects or resulting three-dimensional effects are obtained in continuous strips of tissue paper that are much more significant than conventional DESL. Another difference or advantage of the concept of this invention is the perfect and stable synchronism/phase resulting between the continuous strips of upper and lower tissue paper, which guarantees the embossing effect of the final product.

Description of the drawings.

For a better understanding of this Invention, a detailed description of it is made below, making references to the attached drawings.
Figures 1 to 7B are schematic views exemplifying the conventional embossing processes.
Figure 8 shows a schematic view of an embossing module according to the present invention.

Detailed description of the invention.

According to the illustration in figure 8 and in its details, this ASSEMBLY FOR PROGRESSIVE EMBOSSING OF PAPER SHEETS is characterized by comprising:

At least two embossing stages, one upper (10) and one lower (11), as well as a progressive intermediate stage (12), all of them for the respective continuous strips of tissue paper (1A) and (1N);
the upper embossing stage (10) is formed by a rubber roller (3) that rotates clockwise and, under it, a steel roller (2) with engraving (4) is pressed and that rotates counterclockwise, passing between these rollers (2-3) the continuous strip of tissue paper (1A);
the lower embossing stage (11) is formed by a rubber roller (3) that rotates counterclockwise, and a steel roller (2) with engraving (4) and rotates clockwise is pressed on it, passing continuous strips of tissue paper (1N) between these rollers (2-3);
the third or progressive intermediate stage of embossing (12) is formed by the same steel rollers (2), both are synchronized, where the engravings (4) are male and female, between which the continuous strips of tissue paper (1A) and (1N) pass simultaneously;
at least one of the continuous strips of tissue paper (1A) and (1N) receive adhesive from glue applicator rolls (8) tangentially mounted on the steel rolls (2) on the inlet side of the continuous strips of tissue paper (1A) and (1N); and
after the third or intermediate progressive embossing stage (12) the continuous strips of tissue paper (1A) and (1N) are finished by the probe roller or pressing roller (9).

Continuous strips of tissue paper (1A) and (1N) may vary in terms of the number of layers, i.e., strip (1A) may have more than one layer, as well as strip (1N).

Still regarding figure 8, we have:

X and Y=	rubber penetration
P1/P2=	engraving depth
P1/P2	same or different
X and Y	less than P1 /P2
X = Y
X > Y
X < Y
A and B	final paper deformation
A	greater than X
B	greater than Y

Like the conventional DESL concept, this embossing assembly has only one embossing stage for at least one continuous strip of tissue paper (1A) and one stage for at least one continuous strip of tissue paper (1N) and both are embossed separately. The embossing process is done by the steel/rubber concept and usually in this case the depth/penetration is limited by the inherent characteristics of this process (steel/Rubber).
In the present invention the same concept/stages of conventional DESL are maintained, but we have an additional stage with the steel/steel concept where the continuous strips of tissue paper (1A) and (1N) are embossed simultaneously. In this case we have three stages of embossing in the same module and the embossing process can be done progressively, being in the first and second stages steel/rubber and the third stage or intermediate stage steel/steel.
In the concept of this invention, the limitation of penetration in the third stage would be the engraving depth (P), so we can obtain/reach thickness levels significantly higher than the conventional DESL concept as the main advantage of this concept.
Having higher levels of penetration in the module of the present invention, consequently, we have greater thicknesses in the paper and relief effects or three-dimensional effects resulting in the paper much more significant than the conventional DESL.
Another difference or advantage of the concept of this invention is the perfect and stable synchronism between the continuous strips of tissue paper (1A) and (1N) progressively embossed, which guarantees the embossing effect of the final product.
It will be understood that certain characteristics and combinations of tissue paper strips and steel/steel embossing cylinders may vary considerably while maintaining the same functional concept for the assembly, consequently, it is noted that the construction described in detail as an example is clearly subject to constructive variations, however, always within the scope of the inventive concept herein disclosed of a third intermediate and progressive embossing made with steel rollers that includes DESL mixed embossing, and as many modifications can be made in the configuration detailed here in accordance with the descriptive requirements of the law, it is understood that the present details should be interpreted as illustrative and not limiting.

Claims

ASSEMBLY FOR PROGRESSIVE EMBOSSING OF PAPER SHEETS, characterizing by comprising:
- At least two embossing stages, one upper (10) and one lower (11), as well as a progressive intermediate stage (12), all of them for the respective continuous strips of tissue paper (1A) and (1N);

- the upper embossing stage (10) is formed by a rubber roller (3) that rotates clockwise and, under it, a steel roller (2) with engraving (4) is pressed and that rotates counterclockwise, passing continuous strip of tissue paper (1A) between these rollers (2-3);

- the lower embossing stage (11) is formed by a rubber roller (3) that rotates counterclockwise, and a steel roller (2) with engraving (4) and rotates clockwise is pressed on it, passing continuous strips of tissue paper (1N) between these rollers (2-3);

- the third or progressive intermediate embossing stage (12) is formed by the same steel rollers (2), both are synchronized, where the engravings (4) are male and female, between which the continuous strips of tissue paper (1A) and (1N) pass simultaneously;

- at least one of the continuous strips of tissue paper (1A) and (1N) receive adhesive from glue applicator rolls (8) tangentially mounted on the steel rolls (2) on the inlet side of the continuous strips of tissue paper (1A) and (1N); and

- after the third or intermediate progressive embossing stage (12) the continuous strips of tissue paper (1A) and (1N) are finished by the pressing roller (9).
ASSEMBLY FOR PROGRESSIVE EMBOSSING OF PAPER SHEETS, in accordance with claim 1, wherein said continuous strips of tissue paper (1A) and (1N) have at least one layer of paper each.