HK1236492A1 - A rewinding machine and a winding method for a web of absorbent substrate - Google Patents

Description

Rewinding machine and winding method for absorbent substrate webs

Technical Field

One aspect of the invention relates to a rewinding machine for an absorbent substrate web. Another aspect of the invention relates to a method for winding an absorbent substrate web. Such absorbent substrates can be converted into absorbent sheet products for special, but not exclusive, use for hygiene or household purposes. As an example, rolls of such absorbent sheet products may be used as toilet paper in restrooms. Other uses as napkins, towels, bath towels, wipes, kitchen towels, and the like are possible. These products are manufactured for non-home use or home consumer tissue use.

Background

The absorbent chassis web may be a tissue web obtained by a conventional wet-press or through-air-drying manufacturing process or other manufacturing process. Tissue paper relates to absorbent paper based on cellulose fibres, also known in the art as tissue paper-based sheet. Typical absorbent paper has a caliper of 10 to 60g/m²Preferably 30 to 50g/m²Low basis weight in the range of (1).

The absorbent substrate web may also be a nonwoven web obtained by an air-laid manufacturing process or a spunlaid manufacturing process or other manufacturing processes. Nonwoven fabrics comprising cellulosic fibers relate to an absorbent paper, which in the art is also referred to as a nonwoven material or web made of fibers, such as air laid. Typical absorbent paper has a caliper of 20 to 300g/m²Preferably 40 to 60g/m²Basis weight in the range of (a).

The absorbent substrate web is subjected to various converting steps before being wound into a source roll. One converting step comprises providing the web with transverse perforation/weakening lines with regular spacing. These perforation/weakening lines enable the end user to cut an appropriate length of absorbent sheet material from, for example, a roll.

Document WO 2010/035301 describes a rewinding machine and a winding method. The rewinding machine comprises weakening means for weakening the web material along a substantially transverse weakening line along which the web material is severed at the end of winding of the log. The weakening device is controlled so as to produce a weakening line in a synchronized manner with the completion of the winding of the source roll.

However, at the transition between two successive logs (more precisely, when the completed log is separated from the web and a new log starts to be wound), constraints arise due to the manufacturing set of the logs at industrial manufacturing speeds (up to 1.000m/min), which may cause the web to break in a zigzag manner at the splitting line (i.e. in the machine direction). This effect may even result in longitudinal weakening lines. Therefore, it may further cause propagation of web breaks near the separation occurrence area.

Therefore, there is a need to improve the separation between successive source rolls in a converting machine. Furthermore, this should be achieved in an economical or cost-effective manner.

Disclosure of Invention

The object of the present invention is to propose a rewinding machine that overcomes the drawbacks of the rewinding machines of the prior art. In particular, it is desirable to avoid or at least reduce the formation of a sawtooth edge upon interruption of the web between two successive source rolls. More specifically, the present invention seeks to solve this problem even for absorbent substrate webs that are run at industrial manufacturing speeds (e.g., up to 1.000m/min) in a converting machine.

According to one aspect, there is provided a rewinding machine arranged to wind a web of absorbent substrate into a plurality of logs, the machine comprising a perforation module, a cutting module, a winding module and a control module, the web of absorbent substrate travelling in said modules according to a machine direction,

wherein the perforation modules are arranged to provide the absorbent substrate web with regularly spaced perforation lines oriented generally transverse to the machine direction,

wherein the cutting module is arranged to sever the absorbent substrate web substantially transversely with respect to the machine direction,

wherein the winding modules are arranged to wind a web of absorbent substrate to produce a source roll of the web of absorbent substrate, and

wherein the control module is coupled to the perforation module and the cutting module and controls the module operation such that:

-the control module deactivates the perforation module and activates the cutting module during the transition between two successive source rolls, and

outside the transition phase, the control module activates the perforation module and deactivates the cutting module.

In a transition phase between two consecutive source rolls, the control module may be arranged to deactivate the perforation module and to activate the cutting module from a first time corresponding to a completion of a source roll production cycle between 99.8% and 95% to a second time corresponding to a completion of a subsequent source roll production cycle between 0.2% and 5%.

Outside the transition phase, the control module may be arranged to activate the perforation module and deactivate the cutting module from a first time corresponding to completion of a source roll production cycle between 0.2% and 5% to a second time corresponding to completion of a source roll production cycle between 99.8% and 95%.

According to another aspect, there is provided the use of a rewinding machine for manufacturing a supply roll of absorbent sheet product selected from the group consisting of napkins, towels, kitchen towels, hand towels, toilet paper, wipes and facial tissues.

According to another aspect, there is provided a winding method including the steps of:

-transporting the web of absorbent substrates according to a machine direction,

perforating an absorbent substrate web by providing the absorbent substrate web with regularly spaced perforations oriented substantially transversely with respect to the machine direction,

-winding the web of absorbent substrate to produce a source roll of the web of absorbent substrate,

severing the absorbent substrate web substantially transversely with respect to the machine direction at a transition between two successive logs,

-controlling the perforating step and the severing step so that:

-in a transition phase between two successive source rolls, deactivating the perforating step and resuming the severing step, and

-outside the transition phase, resuming the perforating step and stopping the severing step.

In a transition phase between two consecutive source rolls, the perforating step may be deactivated and the severing step may be resumed from a first time corresponding to the completion of a source roll production cycle between 99.8% and 95% to a second time corresponding to the completion of a subsequent source roll production cycle between 0.2% and 5%.

Outside the transition phase, the perforating step may be resumed and the severing step may be stopped from a first time corresponding to completion of a source roll production cycle between 0.2% and 5% to a second time corresponding to completion of a source roll production cycle between 99.8% and 95%.

According to another aspect, a source roll of absorbent sheet product manufactured according to the winding method is provided.

With the invention it is possible to avoid, at least considerably reduce, the occurrence of constraints which may lead to web breaks in a zig-zag manner when the web is cut at the transition between two successive reels.

Other advantages will become apparent from the following description of the invention.

Drawings

The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

figure 1 is a partial side cross-sectional view schematically showing a converting machine/wire comprising an exemplary embodiment of a rewinding machine arranged to wind a web of absorbent substrate into a plurality of logs; and

figures 2 and 3 are partial perspective views schematically showing the position of the perforation lines relative to the cutting line in the absorbent substrate web at the transition between two source rolls for two different types of perforation lines.

Detailed Description

Fig. 1 is a partial side cross-sectional view schematically illustrating a converting machine/converting line 1 comprising an exemplary embodiment of a rewinding machine 5 arranged to wind an absorbent substrate web 11 into a plurality of logs 30. In this example, the converting machine/converting line 1 comprises two unwinding units 2 and 3, an embossing unit 4 and a rewinding machine 5.

More specifically, at the stage of fig. 1, the absorbent web base webs 10A, 10B have been manufactured according to known papermaking methods. Fig. 1 shows the later stages as stages in which the conversion process takes place. The conversion process converts large parent roll base webs 10A, 10B (e.g., having a bandwidth of from about 1.80m to about 7 m) into retail size rolls 40, e.g., bathroom tissue rolls, tissue rolls (e.g., having a bandwidth of from about 8 centimeters to about 40 centimeters). In this example, the converting machine/converting line 1 produces retail size rolls having two layers.

The first unwind unit 2 provides a first absorbent source roll base web 10A from the first parent roll 7. The second unwind unit 3 provides a second absorbent source roll base web 10B from the second parent roll 8. The absorbent web bases 10A, 10B are both fed to the embossing unit 4.

The various rollers 9 are suitably positioned to control the path of the absorbent web base webs 10A, 10B along the converter/conversion line 1 within each unit 2,3,4,5 and between each unit 2,3,4, 5. The absorbent web bases 10A, 10B travel in the converter/converter line 1 according to the machine direction MD from the unwinding units 2 and 3 towards the embossing unit 4 and towards the rewinder 5.

The embossing unit 4 comprises an engraved cylinder 12 and a cooperating rubber cylinder 13 (which rotate in opposite directions) and a glue dispenser 14. The absorbent web of source webs 10A, 10B are superposed and combined in the embossing unit 4 to form an absorbent substrate web 11. The engraved cylinder 12 may be engraved with a micro-structured pattern (not shown) combining various embossing tips. The engraving cylinder 12 may perform simple or dual stage engraving of the overlapping absorbent web base webs 10A, 10B. The glue dispenser 14 generally includes a tub, an applicator roller, and a dip roller. The applicator cylinder bears the overlapping absorbent web bases 10A, 10B against the engraved cylinder 12. The impregnation roller picks up the adhesive in the vat and transfers the adhesive to the applicator roller. The applicator cylinder is arranged to apply a determined pressure on the engraving cylinder at the distal end areas of the protrusions of the embossed absorbent source web base webs 10A, 10B. Under the determined pressure, the adhesive traverses through both absorbent web bases 10A, 10B. This is used to combine the two webs and also to emboss or micro-emboss at least one absorbent web base web 10A, 10B to create an aesthetic effect or to modify the thickness or softness or flexibility of the resulting absorbent substrate web 11. Such steps are known in the art and are not germane to the present invention and will therefore not be described in detail.

The rewinding machine 5 comprises a perforating module 20, a cutting module 21, a winding module 22 and a control module 50. The rewinder 5 winds the web of absorbent substrate 11 into a plurality of source rolls 30.

The perforation module 20 is arranged to provide the absorbent chassis web 11 with regularly spaced perforation lines oriented substantially transversely with respect to the machine direction MD (i.e. the perforation lines are oriented substantially in the cross direction CD of the machine direction).

The cutting module 21 is arranged to sever the absorbent substrate web 11 substantially transversely with respect to the machine direction (i.e. the separation lines are oriented substantially in the cross direction CD of the machine direction). The severing of the web occurs at the transition phase, i.e. when the first source roll is completed at the end of the source roll production cycle and before the second subsequent source roll is wound starting at the beginning of the new source roll production cycle.

The winding module 22 is arranged to wind the web of absorbent substrates 11 to produce a source roll 30 of the web of absorbent substrates. For example, the winding module 22 is of a peripheral type or a surface type. Winding module 22 comprises a rolling surface 23, a first winding roller 24, a second winding roller 25, a third winding roller 26 and a core supplier 27. The source roll 30 is formed by winding the absorbent substrate web 11 onto a core 41. The cores 41 are supplied in sequence by the core supplier 27 via the rolling surface 23 before a new reel production cycle is started. The source roll 30 is held in place during winding by the first, second and third winding rollers 24,25,26 rotating on the surface in contact with the source roll 30. One of the winding rollers 24,25,26 imparts a rotational movement of the source roll 30.

The control module 50 is coupled to the perforation module 20 and the cutting module 21 by an interface 51. The control module 50 controls the operation of the perforation module 20 and the cutting module 21 in an independent manner. The control module 50 deactivates the perforation module 20 and activates the cutting module 21 in the transition phase between two successive source rolls. The control module 50 activates the perforation module 20 and deactivates the cutting module 21 outside of the transition phase.

During the transition phase between two consecutive source rolls 30, the control module 50 deactivates the perforation module 20 and activates the cutting module 21 from a first time corresponding to completion of about 99.8% of the source roll production cycle to a second time corresponding to completion of about 0.2% of the subsequent source roll production cycle.

Outside the transition phase, the control module 50 activates the perforation module 20 from a first time corresponding to the completion of about 0.2% of a production cycle of the logs to a second time corresponding to the completion of about 99.8% of the production cycle of the same logs, and deactivates the cutting module 21.

Thus, the perforation module 20 operates in about 99.6% of the log production cycle, while the cutting module 21 operates only in about 0.4% of the log production cycle.

The above values relating to the completed source roll production cycle and the operating range are examples, the cycle may extend from 0.2% to 5%, and from 99.8% to 95%, so the operating range may be modified from 99.6% to 90% and from 0.4% to 10%. Operating over the duration of the transition phase enables control of the length of the first sheet in the source roll produced (and thus in the individual rolls produced). The long first sheet can protect the source roll and the individual rolls prior to use, as packaged.

The produced source roll 30 is then cut by a plurality of source roll saws 31 into a plurality of and individual rolls 40 of absorbent material sheets.

Fig. 2 and 3 are partial perspective views schematically illustrating the position of a perforation line 28 or 38 relative to a cut line 29 in an absorbent substrate web 11 at the transition at between two source rolls 30 for two different types of perforation lines.

The absorbent substrate web 11 is fed into the space of the perforation module 20 comprising the perforation roller and the stationary anvil roller. There, the absorbent substrate web 11 is pinched (step S1) out of the desired perforation or tear lines 28,38 (schematically indicated by dashed lines).

The perforation lines 28 according to the first type of perforation (see fig. 2) are lines made in the thickness of the absorbent substrate web 11 according to the cross direction CD in the machine direction and comprise alternating perforated and unperforated sections (i.e. two perforated sections separated by one unperforated section and vice versa). Each unperforated section forms an attachment area between two successive portions (according to the machine direction MD) of the absorbent chassis web 11. Each perforated section forms a separation zone between two successive portions (according to the machine direction MD) of the absorbent chassis web 11. Each of said unperforated/perforated sections is for example between 4mm and 10mm, taking into account the width of the single roll, for example between 10cm and 30 cm.

Two successive lines of perforations 28,38 define respective sheet lengths in respective rolls 40 of absorbent material sheets. For example, sheets of bathroom tissue rolls may have a length of about several tens of centimeters. In fig. 2 and 3, a plurality of dashed lines 32 parallel to the machine direction MD are also shown on the absorbent substrate web 11 for illustration purposes only. The dashed lines 32 are spaced in the cross direction CD of the machine direction. They schematically represent imaginary lines where the absorbent substrate web 11 is to be cut into a plurality of and individual rolls 40. Thus, two adjacent dashed lines define the future edges of a single roll. The distance between two successive dashed lines is equal to the full width of a single roll 40.

After the nipping step (step S1), the absorbent substrate web 11 is wound (step S2) onto the core 41 by the winding module 22 to form a source roll 30.

Once the desired roll diameter (corresponding to a substantially defined number of individual sheets wound in the roll) is reached, the absorbent substrate web 11 is cut or severed. The produced source roll 30 is separated from the web of absorbent substrate 11 (step S3) and a new source roll is then started to be produced. The absorbent substrate web 11 is fed into the space of the cutting module 21 comprising a cutting roll and a stationary anvil roll. There, the absorbent substrate web 11 is cut by a cutting line 29 (schematically represented by two parallel continuous lines). At a transition period Δ t between two consecutive source rolls 30, the perforation module 20 is deactivated and the cutting module 21 is activated from a first time tLn corresponding to the completion of a source roll production cycle of about 99.8% to a second time tLn +1 corresponding to the completion of a subsequent source roll production cycle of about 0.2%.

The loose end of the tail of the web of absorbent substrate 11 forming the resulting source roll 30 is adhered to the source roll in a known manner (step S4).

The generated source roll 30 is then cut parallel to the machine direction MD by a plurality of source roll saws 31 into a plurality of individual rolls 40. The corresponding cuts in the generated source roll 30 are also indicated by a plurality of dashed lines 32 on the surface of the generated source roll 30.

The perforation lines 38 according to the second type of perforation (see fig. 3) differ from the first type of perforation in that the absorbent substrate web 11 is nipped (step S1) out of the staggered perforation lines 38. One of the two central zones in each perforated line is replaced by an unperforated zone and the two successive perforated lines are staggered or offset according to the cross direction CD of the machine direction so that all the central zones are located between two adjacent dashed lines 32. In other words, each perforated line 38 comprises an alternation of perforated segments and long unperforated segments having a particular perforation pattern. The perforated segment is located in the middle of the full width defined by two adjacent dashed lines 32, more precisely at a distance of e.g. 4mm from the two dashed lines 32 defining the future edges of the single roll 40. The long unperforated segments form attachment regions in the tear line 38 according to the cross-machine direction CD of the absorbent substrate web 11. Furthermore, the long unperforated segments also form a plurality of attachment areas between two successive sections, depending on the machine direction MD of the absorbent chassis web 11. Such a perforation line 38 thus enables the manufacture of a single roll 40 in which the individual sheets are susceptible to tearing. At the same time, the tensile strength of the perforation lines 38 is important during the production of the roll, so that bursts in the absorbent substrate web 11 are avoided, at least substantially reduced. In fact, the break in the absorbent chassis web 11 cannot (at least with difficulty) propagate along the perforation line 38.

The drawings and their description hereinbefore illustrate rather than limit the invention.

Although the invention has been described in terms of two examples of perforations, these are not limitative examples. Those skilled in the art will readily recognize that other types of perforations are possible.

Further, the peripheral type or surface type winding module is merely an example. The invention is also applicable to other types of winding modules, for example winding modules using spindles. Furthermore, the present invention is not limited to a source roll formed around a core of paperboard or plastic. In the winding step, the source roll may be coreless, or the core may be temporarily present during winding and removed at the end of the production process.

Furthermore, although the figures show a specific horizontal positioning of the different modules/units/machines relative to each other in the conversion line, this is only an example, as the modules/units/machines may be positioned in a vertical position or a combination of horizontal/vertical positions. The relative positions of the perforation module and the cutting module may be reversed. The conversion line may also comprise additional modules/units/machines for performing specific conversion steps not described herein. Furthermore, the conversion of two layers is only an example, as the invention will be applicable to end products comprising one or more than two layers.

The use of absorbent products is widespread in the field of hygiene or household applications, such as napkins, towels, kitchen towels, hand towels, toilet paper, wipes, facial tissues, bath towels, etc.

Any reference sign in a claim should not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims (8)

1. A rewinding machine (5) arranged to wind a web of absorbent substrate (11) into a plurality of logs (30), said rewinding machine (5) comprising a perforation module (20), a cutting module (21), a winding module (22) and a control module (50), into which module said web of absorbent substrate (11) travels according to a Machine Direction (MD),

wherein the perforation module (20) is arranged to provide the absorbent substrate web (11) with regularly spaced perforation lines (28,38) oriented substantially transversely with respect to the Machine Direction (MD),

wherein the cutting module (21) is arranged to sever the web of absorbent substrate (11) substantially transversely with respect to the Machine Direction (MD),

wherein the winding module (22) is arranged to wind the web of absorbent substrate (11) in order to produce a source roll (30) of the web of absorbent substrate, and

wherein the control module (50) is coupled to the perforation module (20) and the cutting module (21) and controls the module operation such that:

-in a transition phase (Δ t) between two successive source rolls (30), the control module (50) deactivates the perforation module (20) and activates the cutting module (21), and

-outside the transition phase (Δ t), the control module (50) activates the perforation module (20) and deactivates the cutting module (21).

2. Rewinding machine according to claim 1, wherein, at said transition phase (Δ t) between two consecutive logs (30), said control module (50) is arranged to deactivate said perforating module (20) and to activate said cutting module (21) from a first time (tLn) corresponding to the completion of a log product cycle between 99.8% and 95% to a second time (tLn +1) corresponding to the completion of a subsequent log product cycle between 0.2% and 5%.

3. Rewinding machine according to claim 1 or 2, wherein, outside said transition phase (Δ t), said control module (50) is arranged to activate said perforating module (20) and deactivate said cutting module (21) from a first time (tLn +1) corresponding to the completion of a log product cycle between 0.2% and 5% to a second time (tLn) corresponding to the completion of a log product cycle between 99.8% and 95%.

4. Use of the rewinding machine as claimed in any one of claims 1 to 3 for manufacturing logs of absorbent sheet products selected in the group consisting of napkins, towels, kitchen towels, hand towels, toilet papers, wipes and facial tissues.

5. A winding method, comprising the steps of:

-transporting the web of absorbent substrates according to a machine direction,

-perforating (S1) the absorbent substrate web by providing it with regularly spaced perforation lines oriented substantially transversely with respect to the machine direction,

-winding (S2) the web of absorbent substrate to produce a source roll of web of absorbent substrate,

-cutting (S3) the absorbent substrate web substantially transversely with respect to the machine direction in a transition phase between two successive source rolls,

-controlling the perforating step (S1) and the cutting step (S3) such that:

-at the transition phase (Δ t) between two successive source rolls, stopping the perforating step (S1) and resuming the severing step (S3), and

-outside the transition phase (Δ t), resuming the perforating step (S1) and stopping the severing step (S3).

6. Winding method according to claim 5, wherein, in the transition phase (Δ t) between two successive source rolls, the perforating step (S1) is stopped from a first time (tLn) corresponding to the completion of a source roll product cycle between 99.8% and 95% to a second time (tLn +1) corresponding to the completion of a subsequent source roll product cycle between 0.2% and 5%, resuming the cutting step (S1).

7. Winding method according to claim 5 or 6, wherein, outside the transition phase (Δ t), the perforating step (S1) is resumed and the cutting step (S3) is stopped from a first time (tLn +1) corresponding to the completion of a source roll product cycle comprised between 0.2% and 5% to a second time (tLn) corresponding to the completion of a source roll product cycle comprised between 99.8% and 95%.

8. A source roll (30) of absorbent sheet product produced according to the winding method of any one of claims 5 to 7.