CH687519A5 - Storage roll and process for their preparation. - Google Patents

Description

1

CH 687 519 A5

2nd

description

Technical field

The invention relates to a storage roll, in particular a paper roll with a thin, flexible material web wound onto a squeezable tubular support sleeve to form a spoke coil, e.g. from crepe or tissue. The invention further relates to a method for producing such a storage roll.

State of the art

Toilet rolls typically consist of a cylindrical cardboard tube and a paper web wound onto it. It has been found on various occasions that packing and transporting such rolls could take up less space if they were squeezed.

Packaging with crushed rolls and processes for their production are e.g. known from EP 0 392 581-A1, DE 3 418 951-C2, German divisional application P 3 448 300.4, GB 2 228 463-A or GB 2 143 197-A. The space savings achieved through these methods have to be bought for various disadvantages. According to EP 0 392 581, the pressed paper roll must be edged with an additional inelastic band so that it cannot expand again. In the process known from GB 2 228 463-A, the roll is pressed together so strongly that it remains in its pressed form. As a result, however, the user must use special tools to open the roll, since this is no longer possible by hand.

Satisfactory solutions for achieving volume savings are not yet known. It should be noted that not only the technical, but also the aesthetic aspects are important for the consumer. It is therefore desirable that space-saving products also retain a more or less appealing appearance.

Presentation of the invention

The object of the invention is therefore to provide a storage roll of the type mentioned at the outset which can be packed and transported in a space-saving manner and which largely avoids the disadvantages existing in the prior art.

According to the invention, this object is achieved in that the storage roll has an inner and an outer ring area surrounding it, the material web being wound up in the outer ring area under a higher tension than the inner ring area.

The essence of the invention is therefore that the material web is wound more smoothly on the outside than on the inside. This has led to extremely surprising results: When a cylindrical roller according to the invention is squeezed, a characteristic, space-saving shape is created which differs significantly from that known from the prior art. The role also behaves like a plastically deformable body, i.e. it maintains the shape into which it has been pressed. In contrast, the rolls wound in the usual manner behave more like elastic bodies, i.e. they at least partially go back to the shape they had before being squeezed.

Rolls according to the invention therefore do not have to be pressed in two directions perpendicular to one another before packaging, nor must they be held under pressure by special casings or tapes after the squeezing. From the squeeze, they can also be easily converted back to the original round shape.

The difference in elongation of the material web between the inner and outer ring area caused by the increased tension is preferably at least 10% of the elongation at break (of the material web). Is the wound material web as it is e.g. is common in toilet or household paper rolls, provided with perforations, the elongation at break preferably relates to that of the perforated web.

Since the effect according to the invention is also influenced by the type of material or paper used (surface quality, embossing, stretchability, etc.), the lower limit mentioned is not to be understood as an absolute limit. So it is also possible that differences in elongation of less than 10% lead to success.

If the risk of breakage during the production of the roll according to the invention is to be largely excluded, it is advisable to reduce the elongation caused by the increased tension to max. Limit 70% of the elongation at break. A particularly preferred range for the difference in elongation is between 25 and 40%. The outer ring area then forms, as it were, a stable clamping ring which can absorb and distribute the forces of the inner ring area which occur during the crushing.

The outer ring area need not be particularly thick. As a rule, a thickness of 15 mm or less is sufficient for paper rolls. The thinner the outer ring area compared to the inner one, the better the roll can be deformed. If the thickness is too small, however, it no longer has the required clamping force. Good results can be achieved with thicknesses between 4 and 10 mm. This applies in particular to crepe (> 25 g / m2) and tissue (<25 g / m2). The paper can optionally be single or multiple layers.

The outer ring area is bordered by two transition zones. The stretch increases in the inner transition zone and decreases in the outer one. In a third, intermediate ring zone, the stretch is preferably more or less constant. The third ring zone mentioned can also be omitted.

When using low strains, the outer transition zone may be omitted. It is particularly relevant for ring areas that are wound under considerable tension.

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

2nd

3rd

CH 687 519 A5

4th

The inner and outer transition zones typically each make up about a third of the thickness of the outer ring area. However, this is not mandatory. In particular, the two ring zones mentioned need not be of the same thickness. The outer ring zone can usually be a little thinner.

A method for producing a storage roll according to the invention is characterized in that first an inner ring region is wound onto the squeezable, tubular support sleeve with an essentially constant tension of the material web to be wound up, and then the tension in the web is successively increased to a predetermined difference in elongation.

The inner ring area is thus wound using known technology. Before the storage roll has reached its full diameter, the elongation is increased successively, so that the outer ring region, which is wound according to the invention, is formed.

According to a preferred embodiment, after the gradual increase in tension, a ring zone in which the difference in elongation compared to the inner ring area corresponds at least to the predetermined difference in elongation and an outer ring zone in which the elongation difference is gradually reduced are wound.

A particularly simple method is characterized in that the tension in the material resp. Paper web is generated by increasing the peripheral speed of the storage roll compared to the speed of the material web into the winding machine. The peripheral speed is set via the speed of the roller. This process is based on the principle of the center winder known per se. The method according to the invention is somewhat more difficult to implement with a so-called peripheral winder known per se. This is because the stretch must be introduced into the paper web at the entrance of the winding machine.

The peripheral speed is preferably increased by a value of at least 0.5%, in particular between 0.5 and 10%, preferably by a value of approximately 1.5-5%, in particular by a value of approximately 2-3%. The reference value of these percentages is the circumferential speed that is selected for winding the inner ring area. The upper limit depends on the (absolute) stretchability of the material. With highly stretchable materials, the peripheral speed can also be increased by more than 10%. However, small elongations at break are often preferred for paper.

A device according to the invention for carrying out the method comprises a winding rod for rotating a support sleeve pushed thereon and a drive unit for controlling the speed of rotation. It is characterized by a programmed winding curve with an elevation in the end area, according to which the rotation speed is controlled.

An advantage of this device is that it can be used in a suitable manner to implement the method according to the invention and to produce storage rolls according to the invention simply by changing the winding curve, without the need to replace certain machine parts. The winding curve can be stored on a cam disk. In the case of fully electronic winding machines, it can also be contained as a series of values in an electronic memory (e.g. EPROM).

For the production of packs with e.g. A plurality of paper rolls according to the invention are first wound into wide paper rolls according to the method described above, these are then cut into several short individual rolls, the individual rolls are squeezed together and the squeezed single rolls are pushed into a casing. Finally, the cover is welded.

The invention is not limited to paper rolls. Instead of paper, paper-like, fibrous, at least slightly stretchable nonwovens with a not too smooth surface can also be used.

Further advantageous embodiments and combinations of features result from the following description and the entirety of the claims.

Brief description of the drawings

The invention will be explained in more detail below on the basis of exemplary embodiments and in connection with the drawings. Show it:

1 shows a paper roll according to the invention in the uncrushed state;

2 shows an illustration of a paper roll according to the invention in the squeezed state;

3 shows an idealized representation of the course of the expansion as a function of the radius of the wedge;

Fig. 4 is a schematic representation of a curve for controlling a center winder;

Fig. 5 is a schematic representation of an apparatus for performing the method according to the principle of the center winder.

Basically, corresponding parts are provided with the same reference numerals in the drawings.

Ways of Carrying Out the Invention

Fig. 1 shows an illustration of a paper roll according to the invention immediately after the winding process has ended, i.e. so in the uncrushed state. On a support sleeve 1, which typically consists of a thin cardboard, a e.g. 20-30 m long paper web wound up. This thus forms a paper roll 2, which is typically 9-14 cm wide in the case of a toilet roll. The support sleeve 1 has e.g. a diameter between 4 and 5 cm and the paper wrap one of e.g. 11-12 cm. The paper roll 2 thus typically has a thickness of 5-8 cm.

According to the invention, the paper roll has 2 ring areas with different degrees of stretch

10th

15

20th

25th

30th

35

40

45

50

55

60

65

3rd

5

CH 687 519 A5

6

towards the paper web. In particular, an inner, relatively wide ring area 3 is provided, which is wound with a constant, generally quite low tension. It is surrounded by an outer ring area 4, in which the paper web resp. Stretch is wrapped.

According to a preferred embodiment, the outer ring area 4 is divided into at least three ring zones 5, 6, 7. Within the ring zone 5, the tension of the paper web increases steadily until it reaches a predetermined value. In the adjoining central ring zone 6, the tension remains more or less at the predetermined level. The tension in the outer ring zone 7 is then gradually reduced again.

Fig. 3 illustrates this fact. The radius is plotted on the abscissa and the elongation is plotted on the ordinate. Ro denotes the outer radius of the support sleeve 1. The paper web is glued to this and then wound up with a minimal but more or less constant stretch Eo. Ri denotes the outer radius of the inner ring region 3.

The stretch of the paper web is now gradually increased. It does not have to be a linear increase, as shown in FIG. 3 in the sense of a basic illustration. In practice, it will be an S-shaped ramp. With a certain radius R2 the desired elongation value Ei is reached. An inner ring zone 5 is thus ended and a middle ring zone 6 begins, in which the elongation is kept at the predetermined value Ei. When a certain thickness is reached (R3), the outer ring zone 7 begins, in which the expansion is gradually reduced. The outermost area is again a short piece with minimal stretch. R5 denotes the radius of the entire paper roll 2. In FIG. 3 an annular zone 7 is shown which has an outermost part - between the radii R4 and R5 - in which the elongation again assumes a constantly low value. This value need not be identical to the elongation Eo of the inner ring area 3.

The elongation at break Eb is indicated in FIG. 3. This is the elongation (change in length per unit length) that can be achieved if the paper web is stretched to the point of tearing. The elongation Ei in the outer ring area 4 is considerably smaller than the elongation at break Eb. However, it is preferably at least 10% of the elongation at break Eb. If the stretch in the outer ring area 4 is set too high, there is a risk that the paper web will tear during wrapping (e.g. due to a local weak point). Such an interruption in the production process is of course extremely undesirable. If problems of this type can be ruled out from the outset, it is advisable not to allow the strain in the ring area 4 to increase beyond 70% of the elongation at break. A good working range should be between 25 and 40% relative elongation. A relative elongation of about one third of the elongation at break Eb is particularly preferred.

The elongation at break Eb itself naturally changes from paper type to paper type. It also depends on the strength of the perforation. Perforations with small slots and large webs reduce the elongation at break Eb less than those with large slots and small webs. The strength of the perforation is largely determined by the desired properties of the end product. It is noteworthy that the invention can be used in connection with a wide variety of perforations. The (absolute value) of the elongation at break only limits the scope of the invention in extreme cases (e.g. if it is very small).

Is the (absolute) elongation at break Eb e.g. 6.5% (ie 1 m - possibly perforated - paper web tears when extended by 6.5 cm), then according to a preferred embodiment the minimum difference in elongation between the inner and outer ring area (3 or 4) should be at least 0 , 65% (ie 1/10 of 6.5%). The preferred upper limit is then 4.6% (= 70% relative elongation). If the elongation at break is selected by choosing a stronger perforation e.g. reduced to 5%, then the mentioned 10% resp. 70% limit at 0.5% resp. 3.5% (absolute).

The above-mentioned percentages refer to the difference in the stretch between the inner and outer ring area 3 or. 4. If the relative elongation Eo in the inner ring region 3 is already 5% (relative), then the difference between Ei and Eo should be at least 10% according to a preferred embodiment. The relative elongation Ei should then be at least 15% of the elongation at break Eb. It should be emphasized that the advantageous 60% limit does not refer to the difference in elongation, but only to the elongation at break Eb-

The inner ring area 3 is somewhat wider than the outer 4. As a rule, the inner ring area 3 is two to ten times as thick as the outer one. The thicker the outer ring area 4, the more force resp. He can take up resistance. develop. On the other hand, the thinner it is, the better it can be deformed.

Even when using relatively strong paper, thicknesses of the outer ring area 4 of less than 1.5 cm usually lead to success. Thicknesses of less than 1 cm are preferred. The lower limit for the outer ring area 4 should be about 4 mm. If the Tis-sue is very thin, this value may also be fallen below. A good working area is in any case between 6 and 8 mm.

The ring zones 5 and 7 in the outer ring area 4 are e.g. 1-3 mm wide. The middle ring zone 6 is e.g. 2-4 mm wide. It should be noted that the suitable width of the transition zones (5, 7) is not insignificant from the machine conditions, i.e. depends on the capabilities of the winding machine. The peripheral speed cannot be increased as quickly as desired. An excessively abrupt increase could also lead to a break in the paper web.

Has a paper roll of the above structure

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

4th

7

CH 687 519 A5

8th

very special and unexpected properties. These will be explained in the following.

Fig. 2 shows what happens when the paper roll is deformed in one direction under a squeezing force 8 (see arrows). The cylindrical support sleeve 1 buckles at two corners 9a, 9b. Since the squeezing force 8 acts in the y direction, the corners 9a, 9b lie on the x axis. With increasing squeezing force 8, the inner cross section of the support sleeve 1 deforms into an elongated slot. At the same time, the outer shape of the paper roll also changes. Interestingly, however, an elliptical envelope 11 does not arise, as would be expected with the paper rolls produced according to the prior art. Rather, short sides 10a, 10b form, so that an approximately rectangular shape arises in cross section. This, mind you, without using an additional squeezing force in the x direction.

Along the x-axis, the winding 2 experiences a greater compression than along the y-axis. It is assumed that this effect is due to the “integrated clamping ring” which is formed by the outer ring area according to the invention. In the outer ring area, the individual layers of paper are not only stretched more, but are also pressed against each other more strongly. The static friction prevents the layers from moving freely to one another. Indeed, a rigid, to some extent elastic ring is formed.

In the inner ring area 3, the conditions are different. The layers can shift relative to each other to a certain extent, since they are wound, if at all, with very little tension. This is also a reason why the inner ring area 3 is more compressible overall than the outer ring area 4.

It has been shown that, in the case of packaging with a plurality of squeezed paper rolls according to the invention arranged next to one another, a space saving can be achieved which is of the order of magnitude of 40% compared to the rolls wound according to known methods. This result, which is surprising at first glance, can be explained by the fact that when a paper roll is pressed to a predetermined width B (FIG. 2), the known paper rolls have an envelope curve 11, the length of which is greater than that of the rolls according to the invention (length L).

Another new effect is that the paper roll in any shape in which it is pressed or. has been squeezed, persists and does not deform back on its own. This has e.g. the advantage that the packaging itself does not have to exert any compressive forces on the squeezed paper rolls it contains. When the packaging is manufactured, the rolls can also first be squeezed in a separate unit and then pushed into the provided packaging sleeve without the use of pressing forces. On the consumer side, the crushed rollers can also be simply, i.e. be pressed into the desired round shape by hand.

It is believed that the one just described

"Plastic deformability" of the paper roll comes from the fact that the paper layers shift slightly under the external pressure and, due to the roughness of the surface or arrest the fibrousness of the material in the new position. It does not seem to be insignificant in this context that the inner ring area 3 exerts an outward pressure on the outer ring area 4.

A preferred device for producing a paper roll according to the invention will be described below. Such a device is shown schematically in FIG. 5. It is a winding machine based on the principle of the center winder.

A paper web 12, e.g. about 2.4 m wide, runs over a roller 13 to pull rollers 14. Then it is passed over a perforation roller 16, a perforation head 15 at regular intervals (e.g. 10 cm) attaching the perforation known in toilet rolls or household paper. This is followed by a main roller 17 which cooperates with a chopper roller 18 for cutting the paper web after the winding process has ended.

Six winding rods 22.1, .... 22.6, which are part of a turret arrangement 19, take over the winding of the support sleeves. The turret assembly 19, respectively. whose winding rods 22.1, .... 22.6 are loaded and unloaded by a tube loader 20, respectively. a roller unloader 21.

The machine works essentially as follows. The sleeve loader 20 pushes an empty support sleeve onto the sleeve rod 22.1 located in the position P1. Then the turret assembly 19 is rotated by 60 °. In position P2 glue is applied to the outside of the support sleeve to glue the paper web. In position P3 the winding bar is brought to a predetermined maximum speed. The peripheral speed of the support sleeve is then at least as large, preferably slightly higher than the running speed of the paper web 12.

Then the handover takes place. The paper web is cut off, the accelerated winding rod is regulated to the transfer speed and rotated into position P4, at the same time the free end of the paper web is brought onto the glued support sleeve, and the winding process begins. As the radius of the paper roll increases, the speed is reduced in such a way that the peripheral speed on the outside of the paper roll remains essentially constant.

After the winding process has been completed, the paper web is cut off again and the winding rod is moved from position P4 to position P5. It is braked and then unloaded in position P6.

The parts of the machine described so far, as well as the briefly explained mode of operation, are state of the art. New is the curve according to which the speed during winding (position P4) is determined.

Such a so-called winding curve is shown by way of example in FIG. 4. On the abscissa is the

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

5

9

CH 687 519 A5

10th

Process angle phi and the ordinate the angular velocity w of the winding bar. The process angle phi runs from 0-360 °, starting with the transfer (start of the winding process) and ending again with the transfer (cutting off the paper web and transferring it again to the next winding rod). It grows linearly with time. For example, if 20 rolls are wound per minute, the process angle phi runs from 0 to 360 ° within three seconds. (It should be noted that the process angle phi is not proportional to the radius of the paper roll.)

The speed of the paper web is kept constant. With increasing radius of the paper roll, the speed or Reduce the winding speed of the winding bar. The reduction is not linearly dependent on the time or from the process angle phi. The course of the curve cannot be calculated analytically either, since paper shows a very complex behavior. Last but not least, surface roughness and embossing have influences that can only be determined on the basis of experiments and experience. In any case, the curves available today are empirical in nature and designed exclusively for a constant peripheral speed of the paper roll.

For the production of a paper roll according to the invention, in particular for the realization of an elongation curve according to FIG. 3, there is an elevation in the end region of the curve, e.g. leads to a speed increase of 2%.

The outer ring region 4 (FIGS. 1 and 3) begins in the present example at phi = 220 °. Up to a phase angle of phi = 260 °, the angular velocity is successively increased or. lowered less so that the peripheral speed on the outside of the winding gradually increases to a predetermined value. In the present example, this is about 2% above the paper feed speed of the winding machine. This creates the inner ring zone 5 (see FIGS. 1 and 3).

The difference in circumferential speeds is kept constant between phi = 260 ° and phi = 300 °. In this section, the winding curve according to the invention runs at a constant distance from the winding curve according to the prior art. The ring zone 6 is formed by the difference in speed, in which the paper web has an increased (constant) elongation.

The outer ring zone 7 begins at a process angle phi = 300 °. The difference in speed is gradually reduced, so that - according to the exemplary embodiment presented - the increase is ended at a process angle of phi = 330 °. The winding rod then rotates at the same angular speed as in a winding curve according to the prior art. Shortly before the process angle reaches 360 °, the paper web is cut off, the next (empty) support sleeve is moved into position P4 and the winding process starts again at phi = 0 °.

If the outer ring zone 7 is omitted, i.e. if the difference in elongation is not reduced, relaxation takes place when the paper web is cut off. This usually only affects the last two / three windings, but is in a certain sense uncontrolled. If the difference in elongation is relatively small, this fact is of no further concern. In the case of larger differences in elongation, it is better not to do without the ring zone 7 mentioned.

The exemplary increase in speed by 2% corresponds to a relative elongation difference of approximately 30% at an elongation at break of 6.5%. Since the generated stretch is directly dependent on the difference between the drawing-in speed and the peripheral speed of the paper reel, it is readily possible to derive corresponding ranges for the increase in the angular speed from the information given in connection with FIG. 3 regarding preferred stretching ranges.

How the winding curve shown in Fig. 4 is implemented depends on the type of machine. In the case of a purely mechanical design of the control, in which the speed of the winding rod is predetermined by a cam disk which controls a mechanical transmission, it is sufficient to use a cam disk with a cant according to the invention. The same applies to a semi-mechanical / semi-electrical control, in which the winding curve is tapped from a cam disc and an engine speed is set accordingly (e.g. by means of a mechanically controlled potentiometer). With purely electronic control, the curve is stored in the form of digital values in a programmable memory (PROM, EPROM, EEPROM etc.). A winding machine according to the invention is thus characterized in any case by the winding curve implemented in terms of control.

A production line for the production of paper rolls packed in a space-saving manner initially comprises a winding machine for the production of (e.g. 2.4 m wide) paper rolls with the features according to the invention. Next is a device for cutting the wide rolls of paper into narrow single rolls of e.g. 10 centimeters. Then the single rolls are squeezed. This can be achieved with devices known per se. The individual rolls are then brought into the order required for packaging. For a six-pack, e.g. two rows of three placed side by side. In this arrangement, they are then pushed into a plastic bag, which is then welded as tightly as possible.

Of course, space-saving paper roll packs can also be made differently. Instead of a center winder, a circumferential winder can also be used. The tension of the paper web can e.g. can be adjusted by means of the dancing roller arranged on the input side.

In summary, it can be stated that paper rolls with novel and advantageous properties can be wound by the invention. The paper rolls can not only be transported in a space-saving manner, but are also easy to use for the user.

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

6

11

CH 687 519 A5

12th

Reference list

1

Support sleeve

2nd

Paper wrap

3, 4

Ring area

5, 6, 7

Ring zone

8th

Crushing force

9a, b

Corners

10a, d

Short side

11

Envelope

12th

Paper web

13

role

14

Pull rollers

15

Perforation head

16

Perforation roller

17th

Main roller

18th

Chopper roller

19th

Turret assembly

20th

Sleeve loader

21

Roller unloader

22.1 22.6

Winding rod

Claims (11)

Claims 1. Storage roll with a thin, flexible material web wound onto a squeezable tubular support sleeve (1) to form a storage roll (2), characterized in that the storage roll (2) has an inner ring area (3) and an outer ring area (4) enclosing it ), the material web being wound in the outer ring area (4) under a higher tension than the inner ring area (3). 2. Storage roll according to claim 1, characterized in that the elongation difference caused by the increased tension between the inner and outer ring area (3 and 4 respectively) is at least 10% of the elongation at break (Eb) of the material web. 3. Storage roll according to claim 2, characterized in that the elongation in the outer ring area (4) does not exceed 70% of the elongation at break (Eb) and that the elongation difference is 25-40% of the elongation at break (Eb). 4. Storage role according to one of claims 1 to 3, characterized in that the outer ring area (4) has a thickness of less than 1.5 cm, in particular less than about 1 cm and in particular of at least 4 mm. 5. Storage role according to one of claims 1 to 4, characterized in that the outer ring area (4) is bordered by two ring zones (5, 7), the elongation increasing in the inner ring zone (5) and decreasing in the outer ring (7). 6. Storage roll according to claim 5, characterized in that the inner and the outer ring zone (5, 7) each make up about a third of the thickness of the outer ring region (4). 7. A method for producing a storage roll according to claim 1, in which an annular region (3) is wound onto the tubular support sleeve (1) with an essentially constant tension of the material web to be wound, characterized in that in an outer annular region surrounding said annular region ( 4) the tension of the material web to be wound is increased in order to achieve a predetermined difference in elongation compared to the first-mentioned ring region. 8. The method according to claim 7, characterized in that to produce the outer ring region, the tension is first increased successively, a first ring zone (5) being formed, then to form a second ring zone (6) the difference in elongation compared to the inner ring region (3 ) is kept at least at a predetermined difference in elongation and finally the difference in elongation is gradually reduced, a third ring zone (7) being formed. 9. The method according to claim 8, characterized in that the tension is generated by increasing the peripheral speed of the storage roll during winding compared to the retraction speed of the web. 10. The method according to claim 9, characterized in that the peripheral speed is increased by at least 0.5%, preferably by less than 10%, more preferably by 1.5-5%, in particular by 2-3%. 11. The device for carrying out the method according to claim 7, comprising a winding rod (22.1, ..., 22.6) for rotating a support sleeve (1) pushed thereon and a drive unit for controlling the rotational speed of the Wik- kelstange (22.1 22.6), characterized by Means that contain a programmed winding curve with a speed increase in the end area. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 7