SK286060B6 - Tissue and/or tissue-like material and method for the production thereof - Google Patents

Abstract

Tissue and/or tissue-like material for toilet paper, handkerchiefs, kitchen rolls and the like, which at least in partial areas on at least one of its surfaces is provided with a multitude of micro-fissures, which are open toward the surface, but do not go through said material. A method for producing of tissue and/or tissue-like material, whereby a web of material (7) is inserted into a device (1) incorporating rupturing device, then said web material (7) is gripped between flanks (4.1, 4.2) and finally said material, provided micro-fissures, is removed from said device (1).

Description

Technical field

The present invention relates to a method for producing tissue and / or tissue-like material for the manufacture of toilet paper, handkerchiefs, kitchen paper rolls and the like, as well as tissue and / or tissue-like material produced by the method.

BACKGROUND OF THE INVENTION

Tissue and / or tissue-like material finds versatile use. Such materials include, for example, toilet paper, handkerchiefs, kitchen paper rolls, napkins, paper tablecloths, absorbent and absorbent pads, paper handkerchiefs, dish towels, rags and many other various products.

For the purposes of the present invention, tissue is a product that complies with DIN 6730. Accordingly, tissue is a product which consists wholly or predominantly of pulp fibers, with fine and soft creping and closed formation, made on a paper machine with a dry matter content of more than 90 %, and consists of one or more layers, which are primarily absorbent, with a specific weight per unit layer <25 g / cm ² before creping and a creep wet elongation> 5%.

For the purposes of the present invention, a tissue-like material is one which, unlike a tissue material, is produced by changing the drying process. According to DIN 6730, a tissue-like material is a product made predominantly of pulp fibers with large and soft creping and open formation, which is dry creped on a paper machine and consists of one or more layers, the density of the individual layer before creping <25 g / cm ² and the crepe moisture of one layer after crepe> 55%. Such a material can also be made of waste paper.

In order for such products to be successful for consumers, it is particularly necessary to optimize their properties, such as strength, volume, stiffness to feel, optical properties such as embossed or embossed patterns, and in particular their absorbency.

In order to achieve the desired properties of the end product, such as toilet paper or the like, it is known to process the tissue or tissue-like materials used as starting material by calendering. This affects the surface structure of the starting material, especially in terms of its fineness, smoothness and volume. In such a method, the starting materials are guided between at least two generally rotating rollers, a gap which is adjustable between the two rollers and can be adjusted with respect to the desired properties of the finished product. Especially the absorbency, and especially its increase, can hardly be influenced in this way.

Furthermore, it is known not to use calendering stations, but rather various preparations, to achieve the desired properties. Molding processes of this kind are used predominantly on already doubled material layers in order to influence the optical and bulk properties as well as the substrates of the adhesive layers. In particular, two methods are used here, namely the so-called Unions-Prägung and Stahl / Gumi-Prägung. In the first of these - the Unions-Prägung - the starting material is guided between at least two mutually running rollers, which rollers are provided on their surfaces with radially arranged projections, the cross-section of which is in the form of a blunt pyramid. Here, the protrusions of one cylinder engage in recesses formed through the protrusions of the other cylinder. The starting material passes between the two rolls, being uniformly embossed by the protrusions of the two rolls. The embossing takes place along the sides of the pyramid projections. This produces a product which has punching points embossed at even intervals. However, even in this way, in particular, the absorbency of the material used cannot be influenced, or rather partially, negatively.

The Stahl / Gummi-Prägung uses at least two opposing rollers, like the Unions-Prägung, but only one cylinder is provided with blunt pyramid-shaped projections, which are arranged radially on the surface of one cylinder, while the other cylinder is an elastic cylinder surface, such as rubber. The two opposing rollers are adjusted in such a way that the pyramid projections of one roll penetrate directly into the elastic layer of the other roll and thereby emboss. When the web of starting material is allowed to pass between the two rollers, pyramid projections are embossed which penetrate the elastic layer. Even in this way, however, the properties of the material, such as volume, roughness, softness of the surface areas, as well as the optical properties, cannot be substantially influenced, or rather negatively, in terms of absorbency.

Therefore, it would be desirable to process tissue and / or tissue-like materials that would allow to influence not only material properties such as volume, stiffness to feel, optical properties such as embossed or embossed patterning, but also absorbency.

US 5,490,902 describes a printing method by which a paper product achieves tensile strength not only in the longitudinal but also perpendicular thereto.

For this purpose, the paper web is fed into a printing device, the printing means being provided with a plurality of protrusions formed of two kinds which protrude from the printing means, at least a few sections of the printing means in the vicinity of said protrusions being engraved, respectively. deepened that these sections have a greater height than the sections of said protrusions, which do not lie in the vicinity of engraved or embossed parts. deepened sections. The projections of one type are arranged in the machine direction and the projections of the other type are transverse to it. This achieves an approximation of the ratio of the tensile strength values in the longitudinal direction to the tensile strength in the transverse direction.

US 5,158,521 shows a paper tray in which the loaded paper is printed when removed. For this purpose, a paper path is guided between the two rollers, one roll having radially extending grooves and the other roll having corresponding pressing points which fit into the grooves of the first roll. This creates sections of the paper path.

It is therefore an object of the present invention to provide a method of making a tissue or tissue-like material for use that exhibits improved optical and / or haptic properties and / or increased absorbency.

SUMMARY OF THE INVENTION

According to the invention, this object is achieved by a process for the production of a tissue and / or tissue-like material according to the invention which comprises:

- in a first step, the strip of material leads to a device in which the cracking tool is located, which comprises at least two cracking means comprising side-pressing elements positioned substantially parallel and / or perpendicular to the axis of symmetry which runs through the centers the cracking means, the cracking means being aligned with each other such that the pressing elements of the first cracking means fit into a recess formed between two adjacent pressing elements of the second cracking means.

in a second step, the web of material is held and stretched between the sides, and

- in a third step, take out material equipped with micro-cracks which are on one side of the material but do not completely pass through it.

According to the invention, the printing elements can be in the form of both projections and grooves. It is also possible that one cracking means comprises projections in the form of protrusions and the other cracking means comprises a network of perpendicular grooves in the recesses of which the pressing elements of the second cracking means fit.

By means of the process according to the invention, it is possible to obtain a tissue and / or tissue-like material which exhibits an increased absorbency while meeting the requirements of this material with regard to its softness and stiffness to the touch. Therefore, the tissue and / or tissue-like materials produced by the method of the present invention are particularly suitable for use as toilet paper, handkerchiefs, kitchen rolls, i.e. papers that are highly absorbent.

A special embodiment of the press elements prevents movement of the web of starting material which is guided between the at least two cracking means of the cracking tool, avoiding excessive stretching of the web above the limit of elasticity of the material. In this case, the material strip introduced changes its length, which leads to elongation first in the elastic region and then in the plastic region of the material used. This elongation creates micro-cracks on the strip of material in the region of the push head. The reason for this is the clamping of the material between the sides of the pressing elements, which can be precisely defined by the design of the pressing elements.

The size of the micro-cracks can be varied by precisely matching the parameters of the printing rollers, such as "height of the printing point", "diameter of the printing point", "shape of the printing point", and in particular the gap between the printing elements. On the other hand, the size of the micro-cracks after printing depends of course on the starting material itself. Of these, mention should be made in particular of the thickness, the relative elongation and the creping of the tissue and / or tissue-like material used.

The crack forming tools may be punch presses provided with two punching means in the form of punches which are arranged in one plane, on which the pressing elements are arranged on their two embossing surfaces so that they engage and hold the web of material. Advantageously, however, the cracking tool comprises, as a cracking agent, two rollers by which the micro-cracks are embossed. The rollers may be radially arranged on these rollers.

According to a preferred embodiment of the method of the invention, the micro-cracks in the material are formed transversely to the direction of travel of the material web. Thereby, the tissue and / or tissue-like material produced by the process of the present invention obtains an improved absorbency while at the same time high strength. When processing such tissue and / or tissue-like material, the web is also drawn through the processing apparatus. When micro-cracks are formed in the longitudinal direction of the material, there is under certain circumstances the danger that they will increase by the pulling of the material web itself in the longitudinal direction, which can lead to the belt breaking inside the machine. This could lead to unexpected stopping of the machine due to belt breakage, thereby reducing productivity. In addition, the consequent enlargements of micro-cracks can adversely affect the absorbency of the material.

According to a preferred embodiment, when the pressing elements engage in the recess, a gap h _{b is} formed between its bottom and the head of the engaging pressing element, which corresponds to at least 1.5 times the strip thickness of the material.

Preferably, when the pushers engage in the recesses between its bottom and the head of the engaging pushers of the further cracking agent, a gap h of at most about 1000 µm, preferably at most about 300 µm, and even more preferably at most about 250 µm is formed. Preferably, a gap of at most 1000 µm, preferably at most about 300 µm, and even more preferably at most about 200 µm is formed between the flanks of the adjacent pusher members when the cylinder pusher engages with each other, the gap spacing preferably being at most 100 µm. This gap must be large enough to hold the web of material. Changing this gap, as well as gaps h _b primarily craftsmanship tlačiacich elements, it is possible to obtain materials precisely defined according to the requirements imposed on finished products, which are especially useful in view of their high absorbency.

The invention further relates to a tissue and / or tissue-like material which is provided with at least a portion of at least one surface thereof with a plurality of micro-cracks which are open towards the surface and is produced by the method of the invention.

The tissue and / or tissue-like material according to the invention is of excellent quality. On the one hand, it has firstly the desirable properties in terms of its softness and stiffness required by the consumer with respect to the end products made of this material, and on the other hand it exhibits a significantly higher absorbency compared to materials made from materials known from state of the art. For example, it exhibits at least about 25% increased absorbency with respect to water absorption according to CEN compared to materials produced by conventional embossing ("UNION" or "contraction / rubber") or compared to the starting material. / TC 172 / WG 8N 323, with excellent optical and haptic properties, especially softness and firmness to the touch. Preferably, the absorbency of the material according to the invention is at least about 40%, even more preferably more than about 50% higher than materials produced by conventional methods or starting material.

For the purposes of the invention, micro-cracks are understood to mean cracks that occur on one side of the material according to the invention but do not completely pass through it. This opens the interior of the material towards its surface, so that its absorbency is increased. On the other hand, sufficient strength remains because the cracks do not pass through the entire material. Furthermore, the material according to the invention exhibits better absorption, especially for small particles of dirt, since these are firmly trapped in the micro-cracks. As a result, the material of the invention has significantly improved cleaning properties compared to conventional non-cracks.

The material according to the invention may be single- or multi-layered, in particular double- or multi-layered. three-ply. In particular, the advantage is that material cost savings can be achieved, in particular by eliminating the need to use multiple layers of starting materials to obtain tissue and / or tissue-like materials of the same absorbency. The material can also be made from waste paper.

The material according to the invention exhibits a targeted disruption of the pulp fiber bundles and thus an increased absorbency. At the same time, it has sufficient strength to use. Both of these properties, which are obviously contradictory, are therefore combined by the material according to the invention.

According to a preferred embodiment, the micro-cracks formed in the tissue and / or tissue-like material according to the invention are of a size sufficient, on the one hand, to receive fluid, and, on the other hand, so small that the fluid cannot escape.

According to a particularly preferred embodiment, the micro-cracks in the material are arranged transversely to the fiber direction of the material. This achieves that, despite micro-cracks, the strength behavior of the material remains very good. Preferably, the micro-cracks in the material according to the invention are arranged on a part of the surface of the material. It is further preferred that the micro-cracks are arranged on a portion of the surface alternately on the top and bottom of the material. The portions of the microcracks surfaces may partially touch each other and may vary in size. However, it is preferred that they are separated from one another, in particular by areas which contain untreated and / or only slightly stretched material. A material of this type, despite the targeted disruption of the fiber bundles, exhibits excellent strength with simultaneous high absorbency and a soft textile feel.

Finally, the invention also relates to the use of tissue and / or tissue-like material with micro-cracks such as toilet paper, handkerchiefs, roll kitchen paper, napkins, paper tablecloths, absorbent pads, paper towels, dish towels and / or cleaning cloths and dusters.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages of the present invention will be elucidated in the following on the basis of exemplary embodiments and the accompanying drawings. In the drawings:

Fig. 1 is a side view of a material manufacturing apparatus according to the invention;

Fig. 2 shows detail A of FIG. 1;

Fig. 3 shows detail B of FIG. 2;

Fig. 4 shows a detail view B, rotated by 90 [deg.]; and FIG. 5 is a sketch of the distribution of micro-cracks on the material according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows a device as a whole denoted by 1, with a cracking tool consisting of two rollers 2.1 and 2.2 as cracking means between which the material web 7 runs in the direction of the arrow 9 through these rollers 2.1 and 2.2. Both rollers 2.1 and 2.2 move in opposite directions, as indicated by arrows 10 and 11 for clarity.

Detail A of FIG. 1 is a perspective view of FIG. 2. Both rollers 2.1 and 2.2 have on their surfaces a plurality of pressing elements 3.1, 3.2, the sides of which are arranged approximately parallel and perpendicular to each other and with respect to the axis of symmetry 5 which runs through the centers of rollers 2.1 and 2.2. In this case, the pushing element 3.1 of the first cylinder

2.1 fits into a recess 6.1 formed between two radially adjacent push members 3.2 of the second roller 2.2.

Fig. 3 shows detail B of FIG. 2. The material web 7 guided and extending between the two opposing rollers 2.1 and 2.1 is held and stretched by means of their pressing elements 3.1, 3.2. These press elements have a length 1 _b whose size is usually in the range of approximately 400 to 2000 µm, or even in the case of a grooved cylinder it is endless. The gap size I between the two radially adjacent pressing elements 3 is preferably in the range up to about 2500 µm. If a single grooved cylinder is used, this radial slot is absent.

Fig. 4 is a side view of FIG. 3, rotated 90 °. The material web 7, guided between the two rollers 2.1 and 2.1 running opposite each other, is held between the flanks 4.1 and 4.2 of the adjacent pressing elements 3.1, 3.2. Due to this impediment to the movement of the material web 7 in the region of the heads 8 of the pushing elements 3.1, 3.2, transversely to the direction of movement of the micro-cracks 12. It may also be slightly arched. It is also possible to make the pressing elements 3.1, 3.2 as grooves running radially or axially on the roller (grooved roller). This also extends beyond the range of the punch element. The printing elements 3.1, 3.2 are axial width _b, and the size of which is between about 200 and 1000 pm, but may be continuous (a grooved roller). From the axial width a) of the pressing elements 3.1, 3.2 and the axial width and _{2 of the} depression 6.2, the size a of the axial slot can be calculated. It is in the range up to a maximum of 1000 µm, preferably in the range up to a maximum of about 200 µm, and even more preferably the size and axial gap is less than 100 µm. The press elements 3.1, 3.2 have a height h in the range of approximately 300 to 1500 µm. The gap h1 between the head 8 of the pressing element 3 and the bottom of the depression 6.2 is in the range of approximately 200 to 1000 µm and is at least approximately 1.5 times the thickness of the strip of material 7 to be drawn.

In the Y region of FIG. 3, there is a slight expansion of the material web 7, but no micro-cracks 12 are formed. These micro-cracks 12 are formed in the region X of FIG. 4, the area Z indicates the holding area between the lateral sides 4.2 and 4.2 of the pair of push elements 3.1 and 3.2 in the axial direction.

Fig. 5 shows a sketch of the various regions T, X, Y and Z of the materials according to the invention, which can be produced not only by the rollers of the device 1 as cracking means but also by using cracking tools with cracking means in the form of punches. After the material web 7 passes through the device 1, the regions X are alternately arranged not only on the outer side X.1, but also on the inner side X.2 of the material web 7 and contain micro-cracks 12 in the direction of its movement. With the regions X1 and X.2, the boundary zones in the direction of movement 13 of the material web 7 - regions Y - show a slightly expanded starting material but are free of micro-cracks 12. With the regions X1 and X.2 the adjacent zones represent the holding region - in the direction transverse to the production direction 13 formed by the flanks 4.1 and 4.2 of the pushbuttons 3.1 and 3.2, and are also free of micro-cracks 12. animal effects. Areas T between the areas X, Y and Z are unworked after passing through device 1. Simple replacement, eventually. by changing the push elements 3 on the rollers 2.1 and 2.2 and the geometry and dimensions of the gaps a and 1, micro-cracks 12 can be formed transversely or not only perpendicularly, but also transversely to the production direction in the same or adjacent sub-regions. This is particularly true in the case of using cracking tools with dies in the form of punches instead of cylinders 2.1, 2.2.

In the case where a groove cylinder (axial and / or radial) with radial grooves is used, no Y regions would have to be formed. In such a case in which the micro-cracks form not only transversely but also perpendicularly from the corresponding arrangement of pushers. , for example, in those regions Y which transverse to regions X1 and X.2 at least partially pass into regions Z. In the case of micro-cracks formed exclusively transversely to the production direction, regions Z and Y are exchanged. It is also possible to allow the material web 7 to pass through the device 1 more than once. This will evenly distribute the micro-cracks, but the multiple passage is limited to only a few passages depending on the web material used, otherwise the strength of the material being processed could be reduced. Preferably, the micro-cracks 12 are formed transversely to the fiber direction of the drawn web 7 of material.

A tissue material having a size ranging from 18.5 to 22 g / m ² was processed using a defined device. The thickness of the tissue material used was approximately 150 µm. The length 1 of the pushbuttons 3.1, 3.2 was 700 pm and the width of the pushbuttons 3.1, 3.2 was 350 pm. The height of the pushbuttons 3.1, 3.2 was 700 pm and the width ai of the pushbuttons 3.1, 3.2 was 350 pm. The height of the pushbuttons 3.1, 3.2 was 500 pm, the length _{12 of the} recess 6.1 was 1700 pm and the width a _{2 of the} recess 6.2 was 800 pm. This created a gap of 225 µm, a gap of 500 µm and a gap of 250 µm. Thus, a tissue material according to the invention was produced which, in contrast to the untreated material, had an absorbency increased by 25% and exhibited a soft textile feel. Reduction of the a-slot resulted in an increase in animal action and an increase in the formation of micro-cracks, resulting in an increase in absorbency of about 50%.

By means of the device 1 it is also possible to process not only the monolayer material as described in the previous, but also to use tissue and / or tissue-like materials which have been doubled in the surface finishing preparation step to increase not only the absorbency of these materials, but in order to change their textile character, in particular the softness and stiffness of the surface of the material.

Claims (11)

PATENT CLAIMS A process for the production of tissue and / or tissue-like material comprising: - in a first step, the material web (7) leads to a device (1) in which a cracking tool is provided, which comprises at least two crack-forming means comprising press elements (3) with flanks (4) positioned substantially parallel and / or perpendicular to the axis of symmetry (5) that runs through the centers of the cracking means, wherein the cracking means are aligned with each other such that the pressing elements (3.1) of the first cracking means fit into a recess (6) formed between the two adjacent pressing elements (3.2) of the second cracking agent. in a second step, the web (7) of material between the sides (4.1,4.2) is retained and stretched, and - in a third step, remove from the device (1) material equipped with micro-cracks which are on one side of the material but do not completely pass through it. Method according to claim 1, characterized in that the cracking tool comprises two rollers (2.1,2.2) as cracking agent. Method according to claim 1 or 2, characterized in that the micro-cracks in the material are formed transversely to the direction of travel of the material web (7). Method according to any one of the preceding claims, characterized in that the rollers (2.1, 2.2) of the device (1) rotate against each other. Method according to one of the preceding claims 6 to 9, characterized in that, when the pressing elements (3.1, 3.2) engage in the recess (6), the pressing element (8) engaging between the bottom and the head (8) thereof. 3) creates a gap (h1) that corresponds to at least 1.5 times the thickness of the material web (7). Method according to any one of the preceding claims, characterized in that, when the push elements (3) engage between the flanks (4.1, 4.2) of adjacent push elements (3.1, 3.2), a gap (a) of at most 1000 µm is formed. Tissue and / or tissue-like material for the manufacture of toilet paper, handkerchiefs, kitchen towels and the like, produced by the method of any one of claims 1 to 6, characterized in that at least a portion of at least one surface is provided with a plurality of micro-cracks (12). ) that are open towards the surface but do not cross the material. Tissue and / or tissue-like material according to claim 7, characterized in that the micro-cracks (12) in the material are located transversely to the fiber direction of the material. Tissue and / or tissue-like material according to either of claims 7 or 8, characterized in that the micro-cracks (12) are disposed on a part of the surface. Tissue and / or tissue-like material according to any one of claims 7 to 9, characterized in that the micro-cracks (12) are located on a surface part alternately on the top and bottom of the material. Use of tissue and / or tissue-like material with micro-cracks according to any one of the preceding claims as toilet paper, handkerchiefs, kitchen towels in rolls, napkins, paper tablecloths, absorbent pads, paper towels, dish towels and / or cleaning cloths and dusters .