Core winding machine for forming a master roll core, process for forming such core and tissue paper master rolls with said core

Description

1 / 11 “CORE WINDING MACHINE FOR FORMING A MASTER ROLL CORE, PROCESS FOR FORMING SUCH A CORE AND TISSUE PAPER MASTER ROLLS WITH SAID CORE”

[0001] The present invention relates to a core winder for forming a core for tissue paper master rolls. The present invention further relates to a process for forming such a core and to a tissue paper master roll comprising such a core.

[0002] The present invention is usefully employed in the field of so-called tissue paper typology, i.e., paper for products such as toilet paper, paper towels and the like, particularly for "coreless" applications in which the finished paper roll has no core.

[0003] It is known for making laminated tissue paper rolls consisting of multiple layers, usually two or three layers, from rolls of paper material, called master rolls, which have a greater length but the same diameter as the final paper roll. Such master rolls are obtained by winding, onto a cardboard core usually made in the form of a tubular element, by means of rewinding machines, a sheet of paper previously subjected to several processing stages.

[0004] To form a paper roll for end applications, master rolls are cut into multiple units to produce single paper rolls of shorter lengths.

[0005] In so-called “coreless” roll applications, in which paper is wound in layers to form a roll that nevertheless has no core, a known possible solution involves making the master roll comprising a core, since the latter plays a structural support role during the winding procedure, and subsequently removing the core before cutting the master roll into individual rolls.

[0006] It is known that the extraction step of the traditional cardboard core from the master roll is a critical step, as part of the core itself or the rolled paper is frequently damaged; in particular, paper spirals. Petition 870250084157, dated 09 / 18 / 2025, pp. 40 / 58 2 / 11 of the innermost parts connected to the core are subjected to deformation / tearing.

[0007] To overcome such problems, patent document EP 2711320 B1 describes a coil with a core made of deformable plastic, which is extracted by axial deformation of the same, decreasing its diameter.

[0008] Unfortunately, the method described in that document is limited to the core material, which must have certain mechanical property requirements to deform elastically and be reused, such as a tensile yield strength to modulus of elasticity ratio greater than 2%.

[0009] Furthermore, the described method involves making a core longer than the rolled paper roll, so as to secure the core and deform it axially to allow its extraction. Disadvantages: these types of master rolls are more voluminous than those of a classic master roll, where the core is as long as the paper roll.

[0010] Disadvantages: the cost of plastic cores is higher than that of the well-known cardboard ones and, in addition, they must be discarded when damaged.

[0011] An underlying task of the present invention is to provide a core winder that allows forming a core that is easily extractable, while maintaining the overall volume of the compact master rolls.

[0012] Another objective of the present invention is to provide a process for making such a core and a master roll of tissue paper comprising such a core.

[0013] The task described above, as well as the objectives mentioned and others that will become more evident below, are achieved by a core winder as described in claim 1, a process for forming a core as described in claim 6, and a master roll of tissue paper comprising such core as described in claim 11.

[0014] Other resources are provided in the dependent claims. Petition 870250084157, dated 09 / 18 / 2025, pp. 41 / 58 3 / 11

[0015] Other features and advantages will become more apparent from the description of preferred, but not exclusive, embodiments of a core winder, a process for forming a core, and a master roll of tissue paper comprising such a core, illustrated by way of indication and not limitation, with the aid of the accompanying drawings, in which:

[0016] - Figure 1 shows a side perspective view of a core winder according to a preferred embodiment of the present invention;

[0017] - Figure 2 shows an enlarged detail of the core winder from Figure 1;

[0018] - Figure 3 shows a different side perspective view of the core winder from Figure 1;

[0019] - Figure 4 shows a side perspective view of a cardboard tube being formed by means of the core winder of Figures 1 and 3;

[0020] - Figure 5 shows a side perspective view of a master roll of tissue paper according to the present invention.

[0021] With reference to the attached figures, a core winder marked with reference number 100 is described below.

[0022] The core winder 100 is adapted to form a core 200 for tissue paper master rolls 300 from cardboard strips 201,202.

[0023] According to the present invention, the core winder 100 comprises an unwinding station 10 adapted for unwinding two or more coils 11, 12 from a strip of cardboard 201, 202. As shown in the figures, the coils 11, 12 to be unwound simultaneously are two. Therefore, the core 200 will be formed by two strips of cardboard 201, 202 superimposed one on top of the other, one upper strip being 201 and the other lower strip being 202.

[0024] The 100 core winder comprises a Petition 870250084157, dated 09 / 18 / 2025, pp. 42 / 58 4 / 11 formation station 20 downstream of unwinding station 10.

[0025] The forming station 20 is adapted for spiral winding at least one upper strip 201 and one lower strip 202 being unwound from the coils 11,12 one over the other, joining them to form a tube 203.

[0026] The core winder 100 comprises a cutting station 30 downstream of the forming station 20.

[0027] Cutting station 30 is set up to cut the tube 203 that is being formed to obtain a core 200.

[0028] According to the present invention, the core winder 100 is characterized by comprising a dispensing assembly 40 for an adhesive film 41. The dispensing assembly 40 is configured to unwind an adhesive film 41 connectable to the upper strip 201 to obtain a core 200 at least partially covered by such adhesive film 41.

[0029] The dispensing assembly is configured to connect the adhesive film 41 directly to the top strip 201, preferably cold.

[0030] The adhesive film 41 has an adhesive side and a non-adhesive side. The adhesive side is intended to come into contact with the top strip 201, while the non-adhesive side is intended to come into contact, preferably directly, with the tissue paper that will be wound onto the core 200 during the rewinding process.

[0031] Preferably, the adhesive side should be completely covered by adhesive.

[0032] In particular, the adhesive film 41, once connected to the top strip 201 on the adhesive side, can remain fixed to it.

[0033] In particular, the term “connected” means that an edge of the adhesive film 41 is fixed at a point to the upper strip 201. In other words, at least the free end of the adhesive film 41 is anchored at at least one point to the upper strip 201.

[0034] Advantageously, when the training season 20 Petition 870250084157, dated 09 / 18 / 2025, pp. 43 / 58 5 / 11 rolls strips 201,202 over each other, it also causes the adhesive film 41, previously attached to the top strip 201, to adhere to the top strip 201, so that the top strip 201 is at least partially covered by the adhesive film 41.

[0035] Adhesive film 41 makes the outer surface of core 200 slippery.

[0036] The core 200 is therefore more easily separable and thus extractable from the paper layers compared to known ones, as it is covered by an adhesive film 41.

[0037] Preferably, adhesive film 41 is a plastic film.

[0038] The dispensing assembly 40 is configured to unwind the adhesive film 41 simultaneously with the unwinding of the reels 11, 12.

[0039] According to one embodiment, the adhesive film 41 can be connected to the upper strip 201 manually by an operator. Alternatively, the dispensing assembly 40 may comprise an arm or other element adapted to connect the adhesive film 41 to the upper strip 201.

[0040] According to a first preferred embodiment, the adhesive film 41 is connected to the upper strip 41 at the forming station 20.

[0041] Preferably, the dispensing assembly 40 is placed at the unwinding station 10, upstream of the training station 20.

[0042] In other words, preferably at the start of the process, the adhesive film 41 is dispensed and connected to the top strip 201, i.e., at least the free end of the adhesive film 41 is anchored at at least one point to the top strip 201, before the strips 201, 202 are wound and joined at the forming station 20. In this way, the adhesive film 41, which was connected to the top strip 201 at the forming station 20 at the start of the process, is forced to adhere at each point to the top strip 201 during the winding of the strips 201, 202 when forming the tube 203.

[0043] According to a second modality, Petition 870250084157, dated 09 / 18 / 2025, pp. 44 / 58 6 / 11 Alternatively to the first, adhesive film 41 could also be connected and applied to strip 201 between forming station 20 and cutting station 30.

[0044] For example, the dispensing unit 40 can be placed downstream of the training station 20 and upstream of the cutting station 30.

[0045] Preferably, the dispensing assembly 40 comprises a shaft 42 adapted for engaging with a roll 41' of adhesive film 41 and for unwinding the roll 41' while the unwinding station 10 unwinds the reels 11, 12.

[0046] The 42 axis is, for example, of the expandable type.

[0047] Preferably, the dispensing assembly 40 further comprises a brake 43 configured to tension the adhesive film 41 of the roll 41' that is being unwound.

[0048] More preferably, the core winder 100 comprises a control unit 44 placed in signal communication with the brake 43. Such a control unit 44 is particularly adapted to adjust the braking action of the brake 43 as a function of the unwinding speed.

[0049] Preferably, the dispensing assembly 40 comprises a disc 45 which is integral to the shaft 42 and connected to the brake 23. The brake 43 is configured in particular to brake the disc 45 more or less to adjust the tension of the adhesive film 41 being unwound, depending on the type of cardboard of the strips 201, 202 of the rolls 11, 12 being unwound. In fact, the unwinding speed of the reels 11, 12 depends on the type of cardboard.

[0050] Preferably, brake 43 comprises a pneumatic or electro-pneumatic caliper adapted to act on disc 45.

[0051] Preferably, the core winder 100 comprises a position sensor (not visible in the accompanying figures) configured to detect an interruption in the unwinding of the adhesive film 41.

[0052] This position sensor is preferably placed in signal communication with the control unit 44.

[0053] In particular, control unit 44 is adapted Petition 870250084157, dated 09 / 18 / 2025, pages 45 / 58 7 / 11 to stop the unwinding of coils 11, 12 of adhesive film 41, the winding of tube 203 and the possible cutting of tube 203 if an interruption in the unwinding of adhesive film 41 is detected, for example, due to a tear.

[0054] The present invention is applicable to core winders of known type 100, mounting on them the dispensing assembly 40 for adhesive film 41 and configuring the control unit 44 appropriately.

[0055] The unwinding station 10, the forming station 20 and the cutting station 30 are therefore preferably of the known type.

[0056] Preferably, the unwinding station 10 comprises two or more unwinding rollers 13, 14, each adapted to accommodate a coil 11, 12 and to unwind the respective coil 11, 12.

[0057] The dispensing assembly 40 is preferably mounted downstream of the unwinding rollers 13, 14.

[0058] Preferably, the unwinding station 10 also comprises a changeover roll 15, 16 for each unwinding roll 13, 14. The changeover rolls 15, 16 intervene by exchanging places with the unwinding rolls 13, 14 when the coils 11, 12 on the unwinding rolls 13, 14 end.

[0059] Preferably, the unwinding station 10 comprises an oil applicator 17 configured to apply oil to a lower surface of the lower strip 202 from a first roll 11 being unwound from a respective unwinding roll 13.

[0060] Preferably, the unwinding station 10 comprises a glue applicator 18 configured to apply glue to a lower surface of the upper strip 201 from a second roll 12 being unwound from a respective unwinding roll 14. In this way, it is possible to join the upper strip 201 to the lower strip 202 in the formation of the tube 203.

[0061] The oil applicator 17 and the glue applicator 18 are known, as well as the change rollers 15, 16. Petition 870250084157, dated 09 / 18 / 2025, pp. 46 / 58 8 / 11

[0062] The training station 20 preferably comprises a support spindle 21 and belts 22 which are of a known type.

[0063] Preferably, the core winder 100 also comprises a transfer station 50 interposed between the forming station 20 and the cutting station 30. The transfer station 50 is adapted to allow the glue to dry and the tube 203 formed during transport from the forming station 20 to the cutting station 30 to stabilize.

[0064] According to the second embodiment, the dispensing assembly 40 can be placed in any position within the transfer station 50.

[0065] Preferably, adhesive film 41 is an adhesive tape, preferably having a polymeric backing, for example PE, PP or PVC.

[0066] Advantageously, adhesive film 41 is already available in roll form with pre-applied adhesive, and therefore there is no need to form a roll of adhesive film 41 or provide glue sets to apply the adhesive to a non-adhesive film. This significantly simplifies both the core winder structure 100 and the core forming process 200.

[0067] Another part of the present invention is a process for forming a core 200 for tissue paper master rolls from cardboard strips 201, 202.

[0068] The process according to the present invention comprises a step of unwinding two or more coils 11, 12 of a strip of cardboard 201, 202.

[0069] The process also comprises a spiral winding step of at least one upper strip 201 and one lower strip 202 being unwound from coils 11,12 one over the other, joining them to form a tube 203.

[0070] The process also includes a cutting step of the tube 203 that is being formed to obtain a core 200. Petition 870250084157, dated 09 / 18 / 2025, pages 47 / 58 9 / 11

[0071] According to the present invention, the process further comprises a step of unwinding an adhesive film 41 connectable to the upper strip 201 to obtain a core 200 at least partially covered by the adhesive film 41.

[0072] This process can preferably be carried out using the 100 core winder described above.

[0073] Preferably, the unwinding step of the adhesive film 41 is simultaneous with the unwinding step of the two or more reels 11, 12.

[0074] Preferably, the process comprises an additional step of connecting the adhesive film 41 to the top strip 201. The step of connecting the adhesive film 41 involves attaching the adhesive side of the adhesive film 41 to the top strip 201. Preferably, the adhesive side of the adhesive film 41 is attached directly to the top strip 201.

[0075] Advantageously, with the winding step, the adhesive film 41, previously connected to the upper strip 201, is also adhered to the upper strip 201, so that the upper strip 201 is at least partially covered by the adhesive film 41.

[0076] Preferably, the steps of unwinding the adhesive film 41, connecting the adhesive film 41 and winding are performed cold.

[0077] According to one embodiment, this connection step is performed manually by an operator, preferably at cutting station 30.

[0078] Preferably, the connection step is performed before the cutting step.

[0079] According to the first preferred embodiment, the connection stage is performed before the winding stage.

[0080] Alternatively, according to the second method, the connection step can be carried out after the winding step and, in any case, before the cutting step. Petition 870250084157, dated 09 / 18 / 2025, pages 48 / 58 10 / 11

[0081] Preferably, the adhesive film 41 is connected to the upper strip 201 while the machine is stopped, after the adhesive film and strips 201, 202 have been unwound in sufficient quantity to reach the cutting station 30. Subsequently, the core winder 30 is activated and continues unwinding the adhesive film 41 and the reels 11, 12, while simultaneously starting the winding of strips 201, 202 to form the tube 203, which, once a predetermined length is reached, will be cut.

[0082] Preferably, the process also includes a braking step of the unwinding of the 41' roll of adhesive film to tension the 41' adhesive film.

[0083] Preferably, the process also includes a stop step of the dispensing assembly 40 if an interruption in the unwinding of the adhesive film 41 is detected. This step also involves interrupting the unwinding of the reels 11, 12, the winding of the strips 201, 202 and the cutting of the tube 203 that is being formed.

[0084] Preferably, the process also comprises a step of applying oil to a lower surface of the lower strip 202 of the first roll 11 being unwound from a respective unwinding roll 13.

[0085] Preferably, the process also comprises a step of applying glue to a lower surface of the upper strip 201 of the second roll 12 being unwound from a respective unwinding roll 14.

[0086] The oil application step and the glue application step are preferably carried out simultaneously and according to known methods, before the winding step.

[0087] Another part of the present invention is a 300 tissue paper master roll. This 300 master roll forms the precursor to one or more coreless or “without core” type tissue paper rolls.

[0088] The master roll 300 comprises a core 200 comprising at least one top strip of cardboard 201 and a bottom strip of cardboard 202, spirally wound one over the other and joined together. Such core 200 Petition 870250084157, dated 09 / 18 / 2025, pp. 49 / 58 11 / 11 also comprises an adhesive film 41 placed covering at least partially the top strip 201. The adhesive film 41 preferably covers the cardboard completely.

[0089] Adhesive film 41 comes into direct contact with the top strip 201.

[0090] The master roll 300 comprises at least one layer of tissue paper 400 wound continuously in spirals on such a core 200.

[0091] The tissue paper layer 400 comes into direct contact with the adhesive film 41, on the non-adhesive side.

[0092] The 400 tissue paper layer is attached to the 200 core with the first innermost spiral by means of a glue with good “release” properties, i.e., capable of drying and detaching easily.

[0093] Core 200 is preferably manufactured using core 100 winding and the process described above.

[0094] The core 200 of the master roll 300 according to the present invention is similar to known cores, but additionally provides the adhesive film 41 placed to cover the cardboard.

[0095] In fact, core 200 is intended to be subsequently extracted from master roll 300.

[0096] Advantageously, the adhesive film 41 applied over a cardboard core reduces friction and increases smoothness between the core 200 and the sheets of tissue paper wound in spirals over it, facilitating the detachment of the sheets from the core 200 itself when the core 200 is extracted.

[0097] The core winder, process and master roll thus conceived are susceptible to numerous modifications and variants, all within the scope of the inventive concept; moreover, all details are replaceable by technically equivalent elements. In practice, the materials used, provided they are compatible with the specific use, as well as the contingent dimensions and shapes, can be any, depending on the technical requirements.

[0098] Barzanò & Zanardo SpA Petition 870250084157, dated 09 / 18 / 2025, pages 50 / 58

Claims

1 / 3 CLAIMS 1. Core winder (100) for forming a core (200) for tissue paper master rolls (300) from cardboard strips (201, 202), said core winder (100) characterized in that it comprises: - an unwinding station (10) adapted for unwinding two or more rolls (11, 12) from a cardboard strip (201, 202); - a forming station (20) downstream of said unwinding station (10); said forming station (20) being adapted for spiral winding at least one upper strip (201) and one lower strip (202) being unwound from said rolls (11, 12) one over the other, joining them to form a tube (203); - a cutting station (30) downstream of said forming station (20); the said cutting station (30) being configured to cut the tube (203) that is being formed to obtain a core (200);the said core winder (100) having as its particularity comprising: - a dispensing assembly (40) for an adhesive film (41), the said dispensing assembly (40) being configured to unwind an adhesive film (41) connectable to the said upper strip (201) to obtain a core (200) at least partially covered by the said adhesive film.; 2. Core winder (100), according to the preceding claim, characterized in that said dispensing assembly (40) comprises: - a shaft (42) adapted to engage with a roll (4T) of adhesive film (41) and unwind said roll (41') while said unwinding station (10) unwinds said rolls (11, 12); - a brake (43) configured to tension the adhesive film (41) of the roll (4T) being unwinded; - a control unit (44) placed in signal communication with said brake (43). Petition 870250084157, dated 09 / 18 / 2025, pp. 51 / 58 2 / 3 3. Core winder (100) according to claim 1 or 2, characterized in that the dispensing assembly (40) is placed in the unwinding station (10) upstream of the forming station (20).

4. Core winder (100), according to claim 1 or 2, characterized in that the dispensing assembly (40) is placed downstream of the forming station (20) and upstream of the cutting station (30).

5. Core winder (100) according to any of the preceding claims, characterized in that it comprises a position sensor configured to detect an interruption in the unwinding of the adhesive film (41).

6. Process for forming a core (200) for tissue paper master rolls from cardboard strips (201, 202), said process characterized in that it comprises the following steps: - unwinding two or more coils (11, 12) from a cardboard strip (201, 202); - spiraling at least one upper strip (201) and one lower strip (202) unwound from said rolls (11, 12) over each other, joining them to form a tube (203); - cutting said tube (203) being shaped to obtain a core (200); said process having as a particularity comprising a step of: - unwinding an adhesive film (41) connectable to the upper strip (201) to obtain a core (200) at least partially covered by said adhesive film (41).

7. Process, according to the previous claim, characterized in that it comprises an additional step of connecting said adhesive film (41) to said upper strip (201).

8. Process, according to the previous claim, characterized by the fact that the aforementioned connection step is carried out before the cutting step. Petition 870250084157, dated 09 / 18 / 2025, page 52 / 58 3 / 3.

9. Process according to claim 7 or 8, characterized in that the connection step is performed before the winding step.

10. Process, according to any one of claims 6 to 9, characterized in that it comprises a stopping step of said dispensing assembly (40) if an interruption in the unwinding of the adhesive film (41) is detected.

11. Master roll of tissue paper (300) characterized in that it comprises: - a core (200) comprising: - at least one top strip of cardboard (201) and a bottom strip of cardboard (202) spirally wound one over the other and joined together; - an adhesive film (41) placed at least partially as a covering for said top strip (201); - at least one layer of tissue paper (400) continuously wound in spirals on said core (200). Petition 870250084157, dated 18 / 09 / 2025, p. 53 / 58

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