EP1044098B1 - Method and device for achieving adhesion between layers of tissue paper - Google Patents

Description

So far, one has to create a layer adhesion between Tissue paper existing layers for manufacturing, for example a tissue hygiene product, e.g. B. kitchen towel, Toilet paper, napkins, handkerchiefs, facial tissues and the like, either using glue, or you have mechanical Tools for creating knurling or embossing used, the layers in the area of the knurled seam or Edge embossing extremely compressed and thus connected to each other were. These procedures are still common today used. Leave the tools used for this but clearly visible imprints on the tissue surfaces, the often, such as B. in the case of knurling, not desired unless you put one on the tissue paper visible surface embossing, at the same time through the Adhesive printing is made between the layers, such as this in the case of edge embossing z. B. with handkerchiefs or Napkins are common (see e.g. EP-A-672 402).

The object (problem) of the invention is a method as well as to create a device that makes it easier Way is possible while largely maintaining the Softness, firmness and absorbency of the tissue paper a good one even with a larger number of layers Layer adhesion between the layers of the tissue product made with it to generate, but without negative by the consumer perceived, clearly visible prints on the outside showing tissue surfaces of the outer layers of the tissue product to leave.

• Zusammenführen von mindestens zwei Lagen Tissue-Papier in einem Walzenspalt; und
• ein- oder beidseitiges Eindrücken einer im Walzenspalt präsenten unregelmäßig rauhen Oberflächenstruktur, wie sie beispielsweise bei einem Schmirgelpapier vorhanden ist, in das Tissue-Papier;

beziehungsweise vorrichtungsmäßig gelöst durch:

• ein Walzenpaar, zwischen dessen Walzen ein Durchlaufdruckspalt besteht; und
• eine mit dem Umfang der Walzen mitlaufende unregelmäßig rauhe Oberflächenstruktur, die auf einer oder auf beiden Seiten des Druckwalzenspaltes vorhanden ist und ähnlich der eines Schmirgelpapiers ist.

In terms of the method, this object is achieved by the following method steps:

• Bringing together at least two layers of tissue paper in a nip; and
• one-sided or two-sided pressing of an irregularly rough surface structure present in the nip, as is present, for example, in the case of emery paper, into the tissue paper;

or solved in terms of device by:

• a pair of rollers, between the rollers of which there is a continuous pressure nip; and
• an irregularly rough surface structure running with the circumference of the rollers, which is present on one or on both sides of the printing nip and is similar to that of an emery paper.

The method and the device have the advantage that for Generation of layer adhesion on glue can be dispensed with and that the mechanical influence of the roller surface on the tissue surface is hardly or not visible. on the other hand By choosing certain boundary conditions, a visible, desired irregular pattern are generated, which for Designing new products can be used. The paper receives after this layer adhesion generation a peach skin-like Surface, which makes the paper feel very soft.

The indentation takes place with a pressure which is sufficient for it to be Area of majority on the fiber composite of each Layers of a multi-layer tissue product Roughness peaks to inter-fiber bonds come between them touching fiber surfaces near-surface fibers neighboring outer sides of the individual layers of the tissue product.

Layer adhesion can also be applied in more than one nip generate and provide nips in succession, the Roller pairs can work with different pressure, e.g. B. increasing pressure. The roller pairs can also with different Pattern. If the product has more than two layers, can the layers through different pairs of rollers / nips be performed.

In addition to the main procedural claim and the Device main claim arise further advantageous Refinements from the subordinate claims subordinate to these.

The invention also relates to the use of Abrasive paper for creating layer adhesion between layers made of tissue paper by indenting the surface structure of the Emery paper in one of at least two layers folded tissue paper in making one for the End use of certain multi-layer tissue product.

The goal is to generate as many layers as possible "Roughness peaks" per unit area of each other to provide arresting tissue papers, each such "roughness peak" sufficient height, inherent strength and Anchor strength must have to be deep enough in the paper to be able to penetrate. Shape, hardness, inherent and Anchoring strength of each "roughness tip" must be such be that in the area of the fiber structure of the tissue paper end faces of the "roughness peaks" in one Press gap under load as high as possible specific Surface pressure arises, which is able to form a fiber Tissue paper that is stacked in at least two layers this surface pressure is exposed to deform so that thereby the surfaces of neighboring fibers in such intimate contact come together that selectively inter-fiber bonds occur, the sum of which leads to the arrest of the finished position Tissue product.

An easy way to do this, so far not followed for example the use of abrasive grain materials for example made of aluminum oxide, silicon carbide or Industrial diamond in a macro grain range P 40 to P 240 (DIN), for example anchored on suitable flexible Abrasive pads or directly on the surface of a massive roller made of metal or a suitable metal shell, that can be wound on a roll core. Furthermore Forms of training are conceivable that are similar to sandpaper Surface structure on or in the form of a Ceramic bowl occur, also on a roller core can be raised and withstands corresponding loads. Adequate solid rollers, e.g. B. All-ceramic rollers with an emery-paper-like Surface structure can be used.

The invention is illustrated below with the aid of Exemplary embodiments described.

The only figure shows a part of a purely schematic Machine for the production of a two-layer tissue product.

Single-ply tissue paper is first made on a tissue paper machine manufactured and then on a special Processing machine into a multi-layer product brought together. When displaying in the drawing two single-layer tissue papers 5 over deflection rollers 1 and 2 one Roll pair 3, 4 fed. The two lanes run through a printing nip 6 provided between the printing rollers a two-layer end product 7 runs out of the printing nip 6. in the Pressure gap 6, the layer adhesion is generated. For this are the Rollers 3 and 4 are provided with a surface structure 8. This Surface structure is like an emery paper with irregular roughness. The surface is preferably with an emery paper covered, whereby an emery paper of the DIN designation P 20 to P 240 come into question, and preferably as dry sandpaper. Of course this can also Surface structure are generated otherwise, such as. B. in Connection with a ceramic roller (sintered grain) or through laser technology or laser engraving technology. It could too Sandblasting of the roller surface can be used. she should but with that of an emery paper of the type mentioned be comparable. There would also be an opportunity endless emery paper with web-like design through the Let the gap run along, so why not the whole Surface of the printing rollers 3 and 4 with the emery paper is occupied, but the emery paper is effective in the gap. There is also the option of only a part, if desired to provide the surface of the roll with this surface structure, z. B. if layer adhesion only at the edge of the end product should be generated, or if one intends to Layer adhesion through a special pattern of this structure Limitation of layer liability Surface structure on partial areas of the surface of the roller (s) according to a desired pattern such as circles, Circular rings, ovals, rectangles, diamonds, also with each other Standing in touch, quasi coherent, possibly with special Alignment of the patterns relative to the machine direction to provide, of course, there is also the possibility of this structure creates a visible, visually striking pattern produce that appeals to the consumer, albeit it In principle, the aim is layer liability through such To produce surface structure so that a visible structure not or only to a very small extent arises. In addition, there is of course the possibility additionally a superimposed special pattern according to one of the usual embossing processes, e.g. B. nested, foot to foot, if necessary to be applied over the entire surface or as a spot pattern, although There is no need to go through this embossing process either to create a layer liability.

Typically, the pressure rollers 3 and 4 are steel rollers educated. The surface structure preferably has this Steel rollers an irregularity in grain size, the grain distribution density and / or the grain shape, where pointed and there can also be angular grains. According to that The exemplary embodiment shown are both pressure rollers 3 and 4 provided with this surface structure. But it could also be sufficient, just one of the pressure rollers with this To provide surface structure and the counter roller as Train steel roller smooth or a rubber roller as To use counter roller. When applying the surface structure on both rollers there is an absolute synchronization of the rollers from of particular importance. There is also the option of Counter roller to use one whose surface is a Sieve structure.

The rubber counter roller can be used with different hardness , for example 25 to 95 Shore A. The plastic sieves can with different sieve fineness from the weave so-called simple to z. B. Four-shaft twill plastic sieves his. It can achieve satisfactory results up to eight tissue layers can be combined. Preferably the Residual moisture of the tissue paper 3 to 10% and in particular 5 to Amount to 8%. It can in terms of tissue quality Raw tissue papers are used. These are primarily from Natural fibers made from wood. Both Softwood (long fiber) and hardwood (short fiber) are used. The fibers are made using conventional chemical pulping processes the pulp production is open, e.g. B. the sulfite or the sulfate process, or mechanical, chemomechanical or Chemothermomechanical digestion processes, such as. B. Wood pulp, CTMP, HTCTMP. If necessary, chemical Auxiliaries, e.g. B. to increase dry or Wet strength and / or absorbency and / or to increase the Added softness. The pulp can be used as a pump pulp as well can also be used as a drying agent. The processing speed in the tissue paper machine is from 30 to 1000 m / minute, preferably 50 to 800 m / minute, more preferred 150 to 600 m / minute and in particular 300 to 500 m / minute.

The method is suitable for raw tissue basis weights in the range between 12 and 40 g / m ² , preferably between 13 and 25 g / m ² , more preferably between 13.5 and 22 g / m ² , in particular between 14 and 19 g / m ² .

Some exemplary embodiments are explained below.

The device became semi-technical Order of magnitude similar to that in the drawing, being two or multiple webs of material through the nip of two rollers that have a rough or roughened surface have. The tests were rough Roll surfaces produced in that the rolls with commercial emery paper was stuck on.

Experiment 1: Cotton quality: handkerchief raw tissue 4-ply fabric composition:
20% eucalyptus sulfate TCF
50% long fiber sulfate TCF
30% committee of the same composition
= 100% dry matter
Weight: 4 x 14.8 g / m ²
Longitudinal breaking load: 21.14 N / 50 mm (4-ply)
Breaking load across: 7.29 N / 50 mm (4-ply)
Thickness 41g: 0.33mm
Softness: 78 handfeel points

Experimental design:

Cotton wool was through a pair of rollers, the surfaces of both Rollers were coated with P 100 grit, passed through. The pneumatic contact pressure was 4.0 to 5.0 bar, which is a line pressure between the rollers from 22 to 26 corresponds to kN / m.

Then there was a very good to good layer adhesion between all locations. On the surface structure of the tissue paper no disturbing change was visible in the outer locations. A The change in the cloth thickness was not measurable.

Experiment 2: Cotton quality: 2-ply raw toilet paper tissue Composition:
40% eucalyptus sulfate TCF
15% long fiber sulfate TCF
15% long fiber sulfite TCF
10% short fiber sulfite TCF liquid
20% committee of the same composition
= 90% dry / 10% pump pulp
Basis weight: 2 x 16.2 g / m ²
Longitudinal breaking load: 9.48 N / 50 mm (2-ply)
Breaking load across: 4.55 N / 50 mm (2-ply)
Thickness 10: 1.01 mm
Softness: 73 handfeel points

Experimental design:

Cotton wool was through a pair of rollers, the surfaces of the both steel rollers were coated with P 100 grit, and then by an embossing (steel / rubber embossing with "Mull" embossing pattern).

When generating the layer adhesion, the pneumatic one was Contact pressure 4.0 to 5.0 bar, which is a line pressure between the Corresponds to rolls of 22 to 26 kN / m, and was in the embossing the pneumatic contact pressure 1.0 to 2.0 bar, which one Gap pressure of 6.5 to 10 kN / m corresponds.

Very good to good layer adhesion was also achieved here there was no visible deterioration in the Surface structure found in the macro area. It was too no change in cloth thickness can be measured. The visible one The surface structure was only changed by the Embossing achieved.

Experiment 3: Cotton quality: toilet paper raw tissue 2-ply fabric composition as in experiment 2
Basis weight: 2 x 16.2 g / m ²
Longitudinal breaking load: 9.48 N / 50 mm
Breaking load across: 4.55 N / 50 mm
Thickness 10 times: 1.0 mm
Softness: 73 handfeel points

Experimental design:

Cotton wool was through a pair of rollers, the surface of one Roller with P 100 grit and the surface of the another roller with a Kufferath Simplex 4-shaft twill polyester sieve monofilament 24.5 / 18 were occupied (contact pressure of both Roll about 4.0 to 5.0 bar, which is a line pressure between the Rolls of 22 to 26 kN / m corresponds) and then by a Embossing unit (steel / rubber embossing, contact pressure 1.0 to 2.0 bar, which corresponds to a gap pressure of 6.5 to 10 kN / m) passed through.

Good layer adhesion was achieved here without any visible Change in the surface structure. A change in The cloth thickness was not measurable.

Experiment 4:

In another experiment, a pneumatic Contact pressure of 6 bar worked, which with a strip width the tissue sample of 200 mm with a line pressure of 50 kN / m equivalent. There was a P 150 emery paper on both rollers used so that the grain side faced the paper and it 2 to 8 individual layers of tissue with the cotton quality according to Experiment 1 used. It was a very good one with two layers Layer adhesion, also very good with three layers Layer liability determined. With four layers the layer adhesion was between the first and second and the third and fourth Location very good, but only between the second and third location Good. The layer adhesion was up to six layers from the outside in decreasing and still present inside, but straight sufficient. In eight layers there was between the innermost layers no more layer liability.

An attempt was made under otherwise identical conditions with a two-layer product and a P 240 emery cloth. Here the layer liability was still demonstrable, but poor until just enough at most. When using another But it may well be material that even with one such grit the layer adhesion is better.

It should be added that the following roll diameter for the Rolls for layer adhesion generation also applied Suitable emery cloth: 100 to 1000 mm, preferably 150 up to 400 mm and particularly preferably 180 to 350 mm.

Claims (16)

1. Method of producing layer adhesion between layers of tissue paper by bringing together at least two layers of tissue paper (5) in a roll nip (6), characterised by pressing in an irregularly rough surface texture (8), present in the roll nip, as found, for example, in an emery paper, into the tissue paper on one or both sides.
2. Method according to claim 1, characterised in that after the pressing in of the surface texture, in place and time, the tissue paper is flattened.
3. Method according to claim 1 and/or claim 2, characterised in that in addition to the pressing in of the surface texture and possibly also in addition to the flattening of the tissue paper, embossing is carried out for a visible surface design.
4. Method according to claim 3, characterised in that the superimposed embossing, serving to produce a decoration and/or volume, is present over the entire area, as a textural embossing or as a spot (motif) embossing, and this is carried out by one of the normal embossing methods, such as, for example nested, foot to foot or other and the layer adhesion is produced independently of the superimposed embossing in a first method step.
5. Method according to any one of claims 1 to 4, characterised in that the paper has a moistness of 3 to 10% and preferably 5 to 8%.
6. Method according to any one of claims 1 to 5, characterised in that the web speed is between 30 and 1,000 m/minute and preferably 300 m/minute.
7. Method according to any one of claims 1 to 6, characterised in that in the pressure roll nip operation is at a line pressure of 5 to 150 kN/m, in particular 6 to 100 kN/m, in particular 7 to 60 kN/m and in particular 10 to 50 kN/m.
8. Method according to any one of claims 1 to 7, characterised in that a raw tissue length is used, the basis weight of which is in the range between 12 and 40 g/m², in particular between 13 and 25 g/m², in particular 13.5 and 22 g/m² and in particular between 14 and 19 g/m².
9. Device for producing layer adhesion between layers of tissue paper with a pair of rollers, between the rollers (3, 4) of which there is a continuous pressure nip (6), characterised by an irregularly rough surface texture (8), running together with the circumference of the rollers, which is present on one or on both sides of the pressure roll nip (6) and is similar to that of an emery paper.
10. Device according to claim 9, characterised in that a pair of flattening rollers is arranged after the pair of pressure rollers.
11. Device according to claim 10, characterised in that the surface of one or both pressure rollers (3, 4) is coated at least partially with the surface texture and this optionally forms a pattern such as, for example, circles, rings, ovals, rectangles, rhomboids, over the entire surface or limited to the edge of the tissue product, standing alone and at a distance or touching one another in connection, in some cases orientated at an angle to the running direction of the paper in the machine.
12. Device according to claim 11, characterised in that the surface is coated with an emery paper.
13. Device according to claim 12, characterised in that the emery paper is of the kind of DIN designation P 20 to P 240.
14. Device according to claim 13, characterised in that the emery paper is of the kind of DIN designation P 60 to P 150, in particular P 100 to P 140 and in particular P 120.
15. Use of emery paper for producing layer adhesion between layers of tissue paper by pressing the surface texture of the emery paper into a tissue paper composed of at least two layers.
16. Tissue product, made according to at least one of claims 1 to 7.

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