SE519181C2 - Patterned paper and method for its preparation - Google Patents

Abstract

The invention relates to a multi-layered soft paper web, and a method for forming such. A multi-layered soft paper web consists of at least one layer, showing basis weight variations in a pattern. A base-layer of a fibre furnish is firstly formed on wire (2), whereupon at least one top layer is deposited on top of the base-layer, which is supported by a wire or the like (3, 13, 113, 1113) under the applying of the top layer, whereby the top layer is deposited with a fibre suspension jet, and the hereby deposited top layer is formed with twin wire technology. A pattern is created in connection with the forming of the base layer, or at least one top layer by local redistributions within the layer of at least one substantial part of the solid material in the fibre furnish, whereby the pattern in said layer is created under simultaneous dewatering, and that the local redistributions are dependant of the pattern as well.

Description

nnuø »10 15 20 25 30 519 181 2 layer adhesion which limits the strength of the multilayer product in the z-direction. Starch or some other binder must often be sprayed on the layers before they are glued together.

Simultaneous shaping of a multilayer product can also be applied. Examples of multilayer boxes are described in EP 0 681 057 and the technique is also shown in WO 95/13424, WO 96/35018. However, this method causes several problems. So far, it has proved difficult to achieve acceptable layer coverage with co-formation according to this technique and that this method has been found to give a lack of layer purity. Forming with a headbox and a single drainage unit further limits the possibility of maintaining a low headbox concentration, especially at high speeds and at slightly higher basis weights for tissue (single layer products). A low concentration of foundations is a prerequisite for good strength utilization of the raw material used. In addition, it is impossible to give the layers different basis weight patterns as all layers are formed simultaneously.

Multilayer forming of paper in a sequential double-wire technique using both double-sided and partially single-sided dewatering is described, inter alia, in US 3,82l, 073.

Single-sided dewatering is also described in SE 0002998-3. Double-sided dewatering and multilayer forming of tissue paper or tissue paper in a sequential process are described in WO 99/09249.

The problem of layer bonding which is obtained when each layer is formed separately and then glued together is avoided by the method of the invention mainly by depositing the fiber stock on top of the preformed layer, whereby a good layer adhesion is achieved. This means that the strength of the multilayer product in the z-direction is often determined by the strength of the individual layers in the z-direction rather than by the layer adhesion.

With current technologies, with conventional technology today, it is also very difficult to manufacture a multilayer tissue where each layer has a pattern that is independent of the other layers. Especially the middle layer or intermediate layers have not previously been available in a pattern that is not dependent on the pattern in other layers. This means that you often have to use several layers, which in connection with the conversion are laminated together, eg v -.-. 10 15 20 25 30 519 1181 .g by gluing, embossing or the like, to obtain the product desired to be obtained.

In addition, there are several steps in the conversion, such as embossing, which often leads to an unwanted deterioration of the product.

Description of the invention New products can be obtained by the method of the invention with double wire technique where a pattern with basis weight distribution is created in at least one of the layers during the molding.

Middle layer and outer layer can be given different properties to better match each other.

The middle layer can give bulk or be strength-giving and the outer layer can give softness, roughness or strength. Combinations of e.g. strength and absorption, strength and smoothness, absorption and strength can be improved and optimized by the method giving the opportunity to freely choose and combine the appearance, function and properties of the layers. The two-sidedness can also be reduced with the single-layer web or the product. The reduced duplexity is especially desirable when at least three layers are used.

An object of the present invention is to provide a method for forming a multilayer tissue web comprising at least two layers, of which at least one layer consists of a plurality of distinct, distinct patterns created by basis weight variations.

The layer exhibits basis weight variations in a pattern produced by a patterning wire which has created local movements and redistributions of at least a substantial part of the solid material, such as fibers, fillers and the like, within the layer in connection with the formation during simultaneous single-sided dewatering by double wire technique. the local redistributions depend on the pattern. The pattern thus consists of locally selected areas in the layer containing more material, and locally selected areas with a significantly lower content of material. This means that the basis weight of the layers in the locally selected areas with more material is significantly higher compared with locally selected areas with lower or almost no content of material that has low, no or almost non-existent basis weight.

A multilayer tissue web, which is preferably a single layer tissue paper web which can now compete with a multilayer tissue product and has at least two layers, is formed according to the method of the invention. A base layer of fiber stock is first formed in an optional manner on a wire or the like. Then at least one top layer is applied on top of the base layer. This can then be repeated by repeated application of the method according to the invention for one or more of the top layers, whereby an optional number of layers are formed. The total number of layers in the multilayer product can be anywhere from two to three layers, to virtually any number of layers. The layers are formed on each other in a sequential process in such a way as to create distinct, clear patterns.

By base layer is meant the layer on which the next top layer is formed. That is, the last formed layer is always the base layer, on top of which the top layer is formed. Accordingly, by top layer is meant the layer formed on top of an already formed layer. The first formed layer is formed directly against the wires, ie that layer is not formed on top of an already formed base layer and is thus not a top layer either. In the tissue product, the first formed base layer, as well as any layer, may end up in several different places in the product depending on how it is combined with other layers. Thus, all layers can end up as a lower layer, upper layer or an intermediate layer. A pattern can be created in the first formed base layer when double wire technology is used by local redistributions within the layer, ie in the plane, of at least a substantial part of the solid material in the fiber stock, the pattern in the base layer being created during simultaneous dewatering, and the local redistributions being dependent of the pattern. The first formed base layer of fiber stock can also be formed in any way, with or without a pattern, on a wire or the like.

Thus, in the manufacture of the tissue product, a base layer is first formed, after which at least one top layer is formed on top of the base layer by single-sided dewatering during at least a substantial part of the formation zone with direction away from the base layer.

The base layer can also be formed by single-sided dewatering during at least a substantial part of the forming zone. The first formed base layer is supported by the wire or the like during the application and shaping of the top layer. The top layer is applied with a fiber needle jet and the top layer applied with it is formed with double wire technology. 519 1 181 "A pattern is created in connection with the formation of at least one top layer while the top layer lies on top of one of the previously formed layers. the material in the fiber stock, the pattern in said topsheet being formed on top of any of the previously formed layers during simultaneous dewatering. The second wire consists of the wire carrying the base layer.In the case where patterns have been created in the first formed base layer, according to the method described above, other layers can also be formed without patterns.

The method according to the invention utilizes the possibility of consciously creating one layer on top of another which differs from the previous layer in an independent manner. In this way, products with great possibilities for variation can be produced where both outer layers, as well as one or more intermediate layers, can consist of virtually any pattern.

This has not been possible before and a tissue product with substantially independent constituent layers can be manufactured in a method according to the invention. Yet another object of the invention relates to particular layers with discontinuous patterns. The discontinuous pattern consists of the solid material where selected local areas of solid material within the layer, in the plane, are well delimited from each other and are not connected with other local areas of solid material. Local areas with basis weight are thus separately separated from other areas with basis weight and are thus surrounded by groves with no or almost non-existent basis weight. The separately separated local areas, ie the so-called discontinuous areas of solid material, can consist of smaller or relatively small delimited areas locally defined on the surface, as well as they can consist of continuous extended --ï - areas. The invention also encompasses other patterns which, like the above-described discrete patterns, cannot constitute a self-supporting web either. Another object which is also included in the invention is to create different reinforcement patterns. So-called discontinuous reinforcement patterns but also other 10 15 20 25 30 6. u treat-o u continuous reinforcement patterns are included. Patterns that are also interesting for the invention consist of patterns that provide spacer layers, which in turn can give rise to different properties. By designing different patterns in the layers, the combination of the strength of the inner layer or inner layers and the smoothness and softness of the outer layers can be improved.

According to the invention, further patterns can be created which improve the combination of the absorption capacity of the inner layer or inner layers and the stiffness, softness or strength of the outer layers.

In addition, clear and distinct visual patterns are made that include, for example, logos, signs, letters and symbols, and that patterns created during dewatering can be inserted as one or more of your inner layers. The pattern can consist of geometric, imaginative or pure fantasy patterns or consist of a brand or a pattern that can be associated with the company or the company's products. The invention thus includes patterns which are either purely decorative or purely functional, as well as patterns which are both decorative and functional. The size of the patterns is larger than an opening in the weave pattern on a wire, which normally involves sizes from 0.1 mm and larger. This means that the patterns come up in fiber size and beyond, for example for a logo you are up to 10-10s etc.

Another object of the invention is to obtain a stronger tissue paper. This is obtained in several ways, one of the most important of which is that you can produce a single-layer tissue paper consisting of several layers in the paper machine and obtain an end product, without combining it into a single-layer product, through a greatly shortened manufacturing process.

By producing a single-layer product with the desired basis weight pattern directly in the papermaking process, one or more of your steps in the conversion can be omitted.

Such steps can be, for example, gluing in the case of a lag replacement product and embossing, which in both cases leads to a deterioration of the product via, for example, reductions in strength. The conversion step thus normally means that the strength of the product is often greatly reduced. As a rule, one must compensate for this reduction in strength in one of the previous steps of the process by, for example, using more fibers or stronger fibers. On the other hand, the strength of a finished single-layer product by anus: the method of the invention is not reduced because certain conversion methods can be omitted. This means that the strength utilization of the fiber raw material in the finished product is better because the strength is maintained. In addition, the layers of the single layer product of the invention hold together very well. The improved utilization of strength achieved by the single-layer, multi-layered tissue of the invention can be utilized in your own ways. Fibers with lower strength can be used or you can use a smaller amount of fibers and still achieve the same strength in the product. Alternatively, recycled fibers can be used to a greater extent than has previously been possible. You can thus get a lower fiber cost and also save on new fibers. You can also get a product with a lower basis weight at the same strength conditions, or simply get a stronger product. The improved strength utilization can also be utilized to raise the bulk while maintaining strength, which benefits the softness and absorption capacity of the paper.

A further object of the invention is to be able to manufacture a multilayer tissue paper, which as an end product is used as a single-layer product and where it is possible to create patterns in one or more layers independently of the other layers. The pattern of at least one top layer is formed independently of the pattern in the previous layer. This is solved according to the method described in claim 1 or 2. Being able to create a tissue product where patterns are created with double wire technology on top of an already formed base layer has a significant technical and commercial value and it enables a whole range of different products not previously on the market. .

One of the objects of the invention, which constitutes a commercially very important application, is to create a single-layer product with at least three layers, at least one of the intermediate layers being patterned. In order to produce a single-layer tissue product which is substantially symmetrical, three or more layers are preferably used. Yet another object of the invention is to create a discontinuous layer in the middle. With the same amount of fibers, you thereby get higher bulk compared to if you use only continuous layers. High bulk in the middle, without the fibers having to cover the whole area, gives a better product in terms of absorption and a more positive experience for the customer, for example due to a higher softness and better drapeability.

Layers with continuous, partially discontinuous or completely discontinuous, ie non-self-supporting, patterns can thus be produced. Depending on the choice of layers results in higher strength, reduced stiffening, controlled bending stiffness, increased bulk, higher absorbency, higher storage capacity, lower or higher duplexity.

Brief description of the figures The invention will be described in more detail in the following with reference to the exemplary embodiments shown in the drawings. The dark portions shown on the respective layers in Figures 5-10 represent the locally selected areas which mainly consist of more materials, such as fibers, fillers and the like. The black thus represents the main part of the constituents of the paper within the layer.

Figure 1 shows the formation of a web with two layers where double wire forming in the sense of roll forming is used.

Figure 2 shows the formation of a web with four layers where double wire formation in the sense of roll forming is used.

Figure 3 shows the formation of a layer by means of double wire forming in the sense of hybrid forming, ie some pre-dewatering takes place before the double wire nip.

Figure 4 shows multilayer forming on a planar wire where double wire forming is used to form secondary layers by means of upward drainage units for upward drainage placed after secondary headboxes.

Figure 5 shows a discontinuous pattern in an intermediate layer.

Figure 6 shows different discontinuous patterns.

Figure 7 shows discontinuous patterns with continuously extending fiber areas.

Figure 8 shows a so-called discontinuous reinforcement pattern, a so-called trick-track pattern.

Figure 9 shows different reinforcement patterns.

Figure 10 shows three patterned layers for a tissue paper web. Description of Figures and Embodiments According to the embodiment shown in Fig. 1, a top layer is formed in a two-layer structure by a fiber needle beam from a headbox 1 is inserted into a double wire nip created between a tensioned forming wire 2 and another tensioned wire 3 and where both enclose a forming roll 4. Another preferred embodiment is when a three-layer structure is formed.

But the number of layers is optional, which can be seen in Figure 2 which shows a four-layer structure. What mainly characterizes the invention is that the formation of the top layer takes place on top of a base layer or previous top layer by a redistribution within the layer, ie in the plane of substantially the entire fiber stock in the current layer while single-sided dewatering is used in connection with this formation. A movement of at least a substantial part of the solid material in the top layer takes place in such a way that the fibers, fillers and other solid components in the fiber stock are transported and follow the water to and accumulate in the areas where the water is drained by the wire or the like.

In the areas of the layer where the drainage is small or non-existent, there will be a correspondingly small or non-existent amount of fibrous material as well as of other solid constituent components in the fibrous stock. A number of different layers with different patterns and shapes can hereby be achieved, see for example Figs. 5-10. This technology can in turn give rise to a diversity of different products, of which a few of the amount of opportunities that open up will be reported in more detail later.

A good layer adhesion is also obtained by the top layer coming into contact with the previous layer while the top layer is in the form of a fiber suspension. A good layer purity and layer formation of the newly applied layer can be obtained because a fiber concentration with a low concentration is dewatered by a new, web-free wire or the like. The single-sided dewatering also results in a good strength in the z-direction in each layer because the water goes in the same direction in each layer separately. In cases where there is double-sided dewatering, a weakness is incorporated in the layer where the water has gone in different directions. Another advantage is that the possibilities for controlling the layer adhesion are great. It may be desirable to induce delamination in a certain plane in the sheet in a subsequent process step, e.g. the creping. This is advantageous in that it is possible to obtain a good tensile strength for the individual layers and a good layer adhesion between the layers where delamination is not desired in combination with a weakened layer adhesion between the layers where lamination desired or a weakened z-directional strength in the layers where delamination is desired. For example, a discontinuous layer 7 shown in Figure 5 has a lower surface where layer adhesion can occur. This results in a weakened layer adhesion which can be used to induce delamination in a subsequent process step.

A further advantage of the invention is that the pattern of the individual layers can be chosen independently of each other. Even for an individual top layer, the pattern can thus be chosen independently of the pattern of other layers. This is thus possible because the top layer is formed on top of the base layer or previous top layer by single-sided dewatering during at least a substantial part of the forming zone with direction away from the base layer or the previous top layer. The base layer is carried by a wire to the next dewatering unit and the top layer is constantly supported by the previously formed fibrous web.

The base layer can be formed with double wire technology, alternatively with other forming techniques.

In addition, a pattern can be created in connection with the formation of said base layer by a redistribution within the layer of at least a substantial part of the solid material in the fiber stock during simultaneous dewatering, whereby local basis weight differences in the plane are achieved. The base layer and / or the top layers can have patterns or be without patterns, these layers can then be freely varied, whereby each layer can be used as outer layer or intermediate layer as well as inner layer.

The double wire technique or double wire forming includes forming methods in which the headbox jet is inserted directly into a double wire nip (Fig. 1-2), hybrid forming, Fig. 3, and also drainage units with upward drainage after secondary headboxes on a flat wire, Fig. 4, or other similar methods. With double-wire technology, all forming methods are thus included here, where two wires form a forming zone. However, for the manufacture of tissue paper, which requires high machine speeds, methods are preferred in which the headbox jet is inserted directly into the double wire nip thereby obtaining a closed forming zone. This category includes roll forming (non: pulsating dewatering pressure), sheet forming (pulsating dewatering pressure) and combinations of these two forming methods. Some examples of such methods are shown, inter alia, in U.S. Pat. No. 3,056,719, EP 0 699 798, EP 0 454 989, WO 95/34713, U.S. Pat. 1 shows roller forming where a fiber jet is inserted directly into a double wire nip formed by two wires running in endless loops.

During at least a substantial part of the formation zone where formation takes place over one or more of curved surfaces 4, 14, 114, 1114, the dewatering takes place unilaterally in that the curved surfaces 4, 14, 114, 1114 are impermeable, whereby dewatering through the inner wire 2, 3, 13, 113 is prevented. Alternatively, unilateral dewatering can be achieved by the inner wire 2 being impermeable. A significant part of the dewatering takes place through the second wire - the outer wire 3, 13,113,1113 - ie the permeable or partially permeable wire. This means that when a base layer is formed over the curved surface 4 or when a top layer is formed over the curved surface 14 of the base layer or formed over curved surfaces 114, 1114 on the previous top layer, dewatering through the layers and the wire carrying the layer or layers is prevented by the wire 2 or the curved surfaces 4, 14, 114, 1114 over which the wire 2 runs are impermeable. The thus single-sided dewatered base layer or top layer is separated from the inner wire 2, 3, 13, 113 over a suction box 6, 16, 116, 1116 and follows with the corresponding outer wire 3, 13, 113, 1113 towards the next forming unit, where a top layer is formed on top of the previous layer . Each dewatering unit should have a good dewatering capacity, especially when high machine speeds prevail.

The invention can thus be applied in a number of different types of forming sections, see for example Figs. 1-4, which, however, all include double-wire technology / double-wire forming.

The double wire formation takes place in a formation zone between wires or the like which run over stationary and / or rotatable machine elements. When the wires run over machine elements in the form of blades or the like which do not provide a continuous surface, single-sided dewatering can be achieved by using impermeable wires or the like. In the case of double-wire forming, the instantaneous dewatering pressure of the voltage of the outer wire is given taking into account its radius of curvature. When the wires run over the rotating rollers, a dewatering pressure can be obtained which, after an ascent phase, approaches a constant level (so-called roller forming according to Webster). This is favorable in the manufacture of tissue paper, for example with regard to the wire retention and the strength utilization of the raw material used. Alternatively, the dewatering takes place with a varying or a pulsating dewatering pressure where the wires run over stationary machine elements, such as stationary blades or strips. In addition to the dewatering pressure which is induced by the viral voltage, among other things, the dewatering can also be strengthened in other ways, for example by means of a vacuum.

Webster roll forming is shown in Fig. 1 where the fiber stock is inserted into the double wire nip at such a rate that the exterior of the tensioned wires 3 they fl are ignored, while maintaining a substantially constant tension during the fl section of the outer wire 3, by supporting the outer wire of a rotating support 5, at least one of which is resiliently or displaceably mounted to compensate for said deflection. The outer wire 3 is thus mounted so that it can be deflected. The radial position of the outer wire during the forming run is thus not given in advance. The radial position of the outer wire along the roll periphery is determined by such factors as the thickness of the fiber stock jet, the material concentration in the fiber stock, the drain resistance of the stock, the wire tension and any vacuum in the feed roll. The beam has sufficient kinetic energy to fl realize the outer wire and penetrate the nip. The webster method is described in e.g. US 3,056,719. The formation can also take place with fixed virage geometry, or fixed suspension which can be seen in US 3,543,834 and US 3,821,073.

According to the invention, the forming is started and completed over the forming roll 4, 14, 114, 1114. Thereafter, the fiber network structure is substantially fixed so that no significant redistribution of the fibers occurs as the web passes over additional dewatering elements. A further consolidation of the web can then take place according to well-known methods such as gusset rollers, suction boxes and the like before the web enters the press section or the drying section or other subsequent units or sections.

The formation of each top layer takes place on an individually selected and adapted wire 3, 13, 113, 1113 or the like in order to be able to create a pattern in the layer. Each layer is therefore given a completely customized wire and through the wire or the like a patterned fiber web is obtained.

In addition, it is easy to change patterns via wire changes.

The pattern may have purely aesthetic qualities, or the purpose of the pattern may be to affect different physical material properties of the finished tissue, which will be described in more detail in the more detailed description of the preferred embodiments shown in Figures 5-10. Examples of properties of the tissue web or product which the invention wishes to be able to influence are bulk, stiffness, strength properties, elongation, absorption properties partly of water and partly of highly viscous liquids, and anisotropy.

The forming wire or the like 3, 13, 113, 1113 for forming at least one of the top layers has a pattern. Areas with impaired drainage force the solid material in the fiber stock, in particular fillers and fibers, to move to the open areas and thus create distinct patterns consisting of different local areas with different basis weights. The distribution or redistribution of the solid material in the fiber stock which takes place during the formation of the top layer on top of the previous layer takes place by dewatering through the wire or by mechanical pressure against the wire or by exposing the wire in some other way that the fibers are redistributed according to the desired pattern in local areas. , so that the fibers dissipate and accumulate. Openings in the top layer are created in such a way that the desired pattern is achieved.

In connection with the shaping and laying of the fiber netting, a special mustering process takes place with this method. During shaping / patterning, local areas with a higher drainage capacity of the wire will give the formed layer areas with higher basis weight while areas with lower drainage capacity of the wire will give areas with a low, lower, no or almost non-existent basis weight of the fibrous web. The deformation or blockages of the wire or the like can be particularly advantageously performed so that it gives the pattern-creating surfaces, the local areas where the pattern is created, a propagation pattern which is substantially independent of the wire weave pattern. This gives a wire with the best possible ability to create a visually clearly desired pattern of the fiber layer. o nu cos: v øuoouo. u -v ua- 10 15 20 25 30 I II nu u o n 0 f '“' n v _ -: nu oo v I I °:: fl ßu '2 n I-UI-fï: i: ° H' °" 2. ' zzg I: * "'.gg nu' .In- nu un o 14 Patterning wires can be used to pattern a paper web or other fiber web in connection with wet forming g. the fiber suspension through the wire is disturbed or controlled in such a way that local basis weight or fiber length variations occur in the fiber web.

The formation of a layer is performed by using a special pattern wire or the like, the wire or the like being provided with means, such as, for example, blockages, which limit the drainage of fl uid through the wire in a given pattern.

The patterning wire can be provided by blocking continuous, discontinuous or partially discontinuous areas of a conventional open wire with cured polymer, the wire being of any material, for example plastic or rubber. The blocked areas can be achieved by the application of other materials, such as thermoplastic, thermosetting plastic, solder, by electrolytic deposition or by application of sealants. A decorative material can be placed on top of a conventional wire to create a composite material. A composite nonwoven wire can be blocked by, for example, felting. These wires also have blocked drainage openings, which can give rise to patterns.

Similar patterning effect can also be obtained by incorporating a patterned wire into the weaving wire, for example in a Jacquard type loom. It can also be conventional weave patterns with a fl eital shaft.

A number of different types of wires can form the basis for the described pattern wires, for example single, double and triple stored wires. The wire can be replaced by fabric or material that can be used in similar ways, such as, for example, film, screen, fabric, felt, membrane, cast membrane, nonwoven, foil or tape. They can have an etched, cut out, punched out, burnt out or a cast pattern. As for ribbons and the like, you can either put a pattern on the ribbon or use a ribbon with a finished pattern.

All conventional wires, bands or the like are included in the invention and can be used according to the method of the invention. Furthermore, the invention intends to use a wire with a plurality of wires arranged in a wire structure with a plurality of drainage openings and a patterning tube area substantially in the plane of the wire intended for the foundation, of which a number of the wires exhibits a permanent deformation that forms one or fl era in the formation of pattern-creating surfaces within the pattern pattern area. In addition, a number of the drainage openings can be at least partially blocked as a result of the deformation, in which case openings or areas can also be very much blocked, which can give one or more stepless transitions from a non-blocked drainage opening to completely or partially blocked drainage openings. This method is described in more detail in the Swedish patent application SE 9903849-9.

According to the invention, the term tissue web and product, in particular a single-layer multilayer tissue, includes your various tissue paper webs and products. It can be paper for personal use and household use, such as toilet paper, kitchen paper, paper towels, towels, face paper, cosmetic paper, handkerchiefs, napkins, dinner napkins, wet wipes, baby wipes, washcloths, kitchen towels and kitchen towels. Other types of paper are also included, especially for commercial and industrial use such as cloths, cloths and tissue for polishing, polishing, oil drying and waste cloths as well as other cloths for industrial cleaning and the like, for example for use in workshops or printing houses. It can also be both dry and wet towels, tablecloths and pre-treated tissue. The paper can be treated during production or post-treated with, for example, liquids, suspensions, solutions, lotions, various chemicals, agents, therapeutic agents or the like.

Paper for other uses is also included, it can be tablecloths, tablecloths, reinforced tissue and nonwoven materials. Other tissue products which may be included in, in the vicinity of or which are closely related to the said products are also considered to fall within the definition of a multilayer tissue product, in particular a multilayer tissue product, according to the invention. In addition, a multilayer tissue product can also be converted to be included in other hygiene products, such as diapers, sanitary napkins, panty liners and incontinence guards. It is contemplated that pulp of all the various variants normally encompassed in the manufacture of tissue paper may be used in this invention. Other pulps of cellulose fiber can also be used. Some examples are the seed hairs from cotton linters, bast cells such as ramie, linen and jute, straw mass, bamboo mass, bagasse, hemp or nylon.

Chemical pulp that can be used includes sulphite, sulphate pulp and organosolph pulp. Mechanical wood pulp used can be abrasive pulp, tin mechanical pulp, refiner pulp and also chemical mechanical pulp. The pulp can be made of fibers from softwood as well as from hardwood. Another important raw material is recycled fiber from committees and recycled paper. In addition, synthetic and semi-synthetic fibers can also be used.

It is also assumed that the fiber mass, before it becomes a fiber stock, can be treated according to all the normal or known treatment methods available. It may be that the fiber or pulp is ground, screened, purified in various ways, bleached, treated chemically and / or mechanically and other things that are part of the normal pulp handling and / or pre-processing.

The finished fiber stock can also contain process chemicals, such as retention aids, or functional chemicals to give the finished product special properties. These can be, for example, retention aids, fl occultants, fillers, various strengthening or strengthening agents, plasticizers, pH-giving or pH-controlling agents, hydrophobing agents, absorbents, stabilizers, bleaches, etc. Agents useful according to the invention are not limited to the above-mentioned agents; but also includes other known or available process or functional chemicals. In addition, the fiber nettle is usually considered to be water-based and that other liquids may be partly or mainly included.

Different types of imaginative or non-imaginative patterns can be applied to any of the layers of tissue paper as a basis weight pattern with one or fl your openings and one or fl your accumulations of fibers representing the desired pattern. What mainly distinguishes the desired pattern from other conventional basis weight patterns -made by other methods- is that the lower basis weight ranges have very low basis weight, almost non-existent or »znaa 10 15 20 25 30 519 181 17 u o. Von no basis weight at all, which creates openings or holes in the layer in question. Holes or openings in one or more inner layers can be enclosed and wrapped by the outer layers. A pattern made according to the method sometimes resembles a watermark, see for example 12, 14 in Figs. 6 and 7.

Discontinuous patterns are shown in the preferred embodiments of Figures 5-7 and are basis weight patterns where the solid material in the fiber stock, especially the fibers and fillers, has accumulated in areas that are completely separated from each other. It is thus the areas in the layer which consist of fibers which constitute the discontinuous pattern. The layer with the discontinuous pattern is therefore not self-supporting and is very difficult to manufacture, if not impossible with conventional methods, but with the method according to the invention this is now possible.

Of course, it is also conceivable to let the pattern-creating areas in, for example, Figs. 6 and 7 consist of empty portions or portions with a lower basis weight than surrounding portions.

A layer with a discontinuous pattern 7 can be used as one or more intermediate layers, as shown in Fig. 5. The discontinuous pattern creates distance or bulk between the outer layers and one can then speak of a distance layer. A discontinuous or differently shaped intermediate spacer layer can create bulk, resulting in higher absorption and storage capacity. In addition, this "bulk feeling" gives a higher positive experience to the consumer. Among other things, highly viscous liquids can be stored in a very advantageous way, but this also applies to other liquids. In the cases where the ritten layer instead of an evenly thick layer gives a differently shaped layer which gives extra bulk, this is compensated with strength in the outer layers. The discontinuous pattern 7 can be chosen freely. Other suitable embodiments of discontinuous patterns 9, 11, 13, 15, 17, 21, 23 are shown in Figures 6-7 and 9. The discontinuous areas of solid material 8, 10, 12, 18 consist of smaller and relatively local to the surface small demarcated areas. The described embodiments in Figs. 7 and 9 show discontinuous patterns 13, 15, 21, 23 which consist of continuously extending areas of solid material 14, 16, 22, 24. The areas: in 15 15 25 25 51-9 181 18 which constitutes the discontinuous pattern can thus in turn consist of discontinuous patterns or continuous patterns.

A pattern in the middle of a product, which is also not self-supporting, opens up opportunities for completely new patterns that in addition to the pure design can also combine both design and functional properties as well as patterns can only be created to give the product a certain function or property. Patterns in the middle layer are protected by outer layers that can be continuous or possibly even partially discontinuous.

One of the important applications that exists comprises a single-layer product with at least three layers, of which an intermediate layer with a pattern which can also be discontinuous, see Fig. 5. The first formed layer, ie the base layer, can constitute the patterned layer, as well as later formed top layers. .

In the cases where reinforced patterns are in demand, it is now also possible to create so-called discontinuous reinforcement patterns, see Fig. 8, such as so-called trick-track patterns 17. In the places where the fiber lines, which are intended to form a reinforcement pattern, would normally have crossed each other, interruptions have been made in this pattern, creating openings. This is especially advantageous because reinforcements also involve stiffeners. By not having a continuous reinforcement pattern but instead using a so-called reinforcement pattern that leaves openings, where the fiber pattern would normally have been crossed, the stiffening effect can be reduced. No fibers bridge each other and the openings are sufficient to break the stiffness. Of course, different continuous reinforcement patterns can also be used in the product, see figure 9.

Other examples of reinforcement patterns that can be created in one or more layers are reinforcements with patterns in the machine direction, 15, 21, fig. 9.

The bending stiffness or elasticity is normally different in the longitudinal and transverse directions of the machine, which not only but perhaps above all stems from the subsequent creping which further reduces the bending resistance, bending the stiffness in the machine direction.

Based on this fact, bending stiffness can be created in the machine direction by strong basis weight patterns 16, 22 in the longitudinal direction 15, 21 of the machine, which in the transverse direction gives a .ø; »| 10 15 20 25 30 519 181 19 alternating strong and weak basis weight pattern. By thus having created a higher bending stiffness in the machine direction which is later reduced in the creping step, a more uniform product, with respect to the bending stiffness or the elasticity in the longitudinal and transverse directions, can be obtained. A reinforcing pattern can also be made so that the layer is reinforced in the transverse direction of the machine 21. This and similar patterns can be used when you want to reinforce the creping effect. As the middle layer acquires strength-giving properties, the outer layers are designed mostly for softness.

According to the invention, the layers can be created and combined in different ways and a single-layer product can be composed in any way. A preferred example of such a product, Fig. 10, is a three-ply tissue paper having an outer layer 30 formed with large openings 31, which facilitates highly viscous liquids or oils to penetrate the material. The middle layer is formed into a bulk-giving layer, for example a discontinuous intermediate layer 32 with fiber accumulations of the solid material 33 which absorb and store the highly viscous material in the middle. The second outer layer consists of a smooth or rough surface which provides good absorption for, for example, water or other low-viscosity liquids. In this way, a two-sidedness has been obtained which, of course, can also have been created in other ways and with other functions completely according to the wishes of the producer or consumer.

Staining in certain layers in combination with the basis weight patterns can create distinct and clear patterns in the product. At least one top layer may be colored differently from other layers. An example is that the fiber stock used for the discontinuous optional pattern has an inner layer dyed in, while the outer layers have a different color. This can be especially effective when figures, brands or other aesthetic and functional patterns are used. See examples of discontinuous and continuous patterns in Figs. 5-10.

Of course, it is also possible to imagine using different fiber meters in different layers. The Yankees side gives a smoother side than the cover side does, while many volume-important products such as toilet paper and kitchen paper should be substantially symmetrical. The two-sidedness given by the Yankee cylinder can be prevented by ~. _ _ - -. .sv .- -u-u -. ~ .- u-v 10 15 20 5-19 181 20 to select the fibers in the layers so as to shift the smoothness of the sides. That is, you choose fibers and perhaps also the shape of the layer so that the side that will be the cover side from the beginning is smoother. Due to the soothing effect of the Yankee cylinder, the smoothness will be evened out through the process.

For the production of substantially symmetrical tissue the higher quality segments, one of the preferred monolayer products consists of at least three layers in combination with a drying process which results in a lower degree of duplexity than Yankee drying does. Thus, it is advantageous if the drying is carried out at least in part as blow-through drying (TAD, through-air-drying) which can give a low degree of two-sidedness. You can then, for example, also use short fiber stock in the outer layers for smoothness and long fiber stock in the inner layers for strength and bulk.

It is difficult, if not impossible, to describe all the variations of products that can be created with the method according to the invention. Therefore, all conceivable variations and variants of the described products are considered to be included in the invention entirely in accordance with the method and products described in the claims and are explained in more detail in the description. The invention should therefore not be considered limited to the above embodiments as these are only intended to clarify the invention. Within the scope of the invention, it is also possible to combine features from different embodiments with each other.

Claims (24)

10 15 20 25 30 519 ”18 1 233 .. i ''“ 21 Patent Claims Method for forming a single-layer, multilayer paper web, preferably for forming a tissue paper web with at least two layers, where a base layer of fiber stock is first formed on a wire or the like (2), after which at least one top layer is applied on top of the base layer, which during application of the topsheet is supported by a wire or the like (3, 13, 113, 1113), the base layer and at least one topsheet being applied with a fiber netting beam and the base and topsheets applied thereby being formed by double wire technique, characterized in that a pattern is created in connection with the formation of the base layer and / or at least one top layer by local redistributions within each layer of at least a substantial part of the solid material in the fiber stock, the pattern in said base layer and / or at least one top layer is created during simultaneous dewatering, and the local redistributions depend on the pattern. Method for forming a multilayer paper web, preferably for forming a tissue paper web having at least two layers, wherein a base layer of fiber stock is first formed on a wire or the like (2), after which at least one top layer is applied on top of the base layer, as during the application of the top layer. supported by a wire or the like (3, 13, 113, 1113), the top layer being applied with a fiber melt jet and the top layer applied thereby being formed by double wire technique, characterized in that a pattern is created in connection with the formation of at least one top layer by local redistributions within the layer of at least a substantial part of the solid material in the fiber stock, the pattern in said top layer being formed on top of any of the previously formed layers during simultaneous dewatering, and that the local redistributions depend on the pattern. Method according to one of the preceding claims, characterized in that the double wire nip comprises a patterning wire, through which the dewatering takes place, which creates the desired local redistributions of the solid material, such as preferably fibers, fillers and the like, in the layer. anwa »10 15 20 25 30 519 181 22 Method according to claims 2-3, characterized in that the formation of said base layer takes place with double wire technique. Method according to claims 2-4, characterized in that a pattern is created in connection with the formation of the base layer by local redistributions within the layer of at least a substantial part of the solid material in the fibrous web, wherein the pattern in said base layer and / or the at least one top layer created during simultaneous drainage, and that the local redistributions are dependent on the pattern. Method according to one of the preceding claims, characterized in that the pattern of at least one top layer is formed independently of the pattern in the base layer or in other top layers. Method according to one of the preceding claims, characterized in that in the manufacture of the paper web a base layer is first formed, after which a top layer is formed on top of the base layer, the forming forming at least one patterned layer taking place by single-sided dewatering during at least a substantial part of the forming zone. away from the base layer. Method according to one of the preceding claims, characterized in that forming and dewatering of at least said layers takes place a forming space between wires or the like which run over one or more curved surfaces (4, 14, 114, 1114). Method according to one of the preceding claims, characterized in that single-sided dewatering of at least said patterned layers takes place in that the forming surface (4, 14, 114, 1114) is non-permeable. Method according to one of the preceding claims, characterized in that the forming of at least one layer is carried out by using a special patterning wire or the like, the wire or the like being provided with means, such as, for example, blockages, which limit the drainage of fl uid through the wire in a given pattern. > |; |: 10 15 20 25 30 en vvo 23 Method according to one of the preceding claims, characterized in that the fiber stock used in at least one top layer differs from the fiber stock used in another layer in its composition in terms of fiber type, chemical additive or the like. A multilayer tissue web, preferably a tissue web having at least two layers, characterized in that it is produced according to the method of any one of claims 1-1 1. A multilayer paper web, preferably a tissue paper web having at least two layers, characterized in that at least one of the layers exhibits basis weight variations in a pattern produced by a patterning wire that creates local displacements and redistributions of at least a substantial portion of the preferably solid material, fillers and the like, within the layer in connection with the forming. A multilayer tissue web according to claim 13, characterized in that at least one top layer is colored in a different way than the other layers. A multilayer tissue web according to claim 13 or 14, characterized in that at least one of the layers consists of a discontinuous layer (7, 9, 11, 13, 15, 17, 21, 23, 32) defined by areas of the layer having a substantially higher basis weight (8, 10, 12, 14, 16, 18, 22, 24, 33) compared to surrounding areas having no or almost non-existent basis weight, so that the solid material, such as preferably fibers, fillers and the like, in the layer (8, 10, 12, 14, 16, 18, 22, 24, 33) consists of a discontinuous, non-self-supporting path. A multilayer tissue web according to claim 15, characterized in that the non-self-supporting layer (13, 15, 21, 23) comprises continuous elongated streaks or stripes consisting of the solid material, such as preferably fibers, fillers and the like, in the layer (14 , 16, 22, 24). A multilayer tissue web according to claim 15, characterized in that the non-11.1: 10 self-supporting layer (13, 15, 21, 23) comprises discontinuous areas consisting of the solid material, such as preferably fibers , fillers and the like, in the layer (8, 10, 12, 18, 33). A multilayer tissue web according to claim 13 or 14, characterized in that at least one of the layers consists of a reinforcing pattern (19, 15, 21, 23), of which substantially all solid material (20, 16, 22, 24), such as preferably fibers , fillers and the like, in the layer constitute the reinforcing pattern, which increases the strength of the paper web in the longitudinal or transverse direction. A multilayer tissue web according to claim 18, characterized in that at least one layer is formed into a pattern which provides reinforcements in the machine direction (15, 21), which gives a higher bending stiffness in the machine direction. A multilayer tissue web according to claims 13-19, characterized in that at least one top layer is formed into a discontinuous reinforcement pattern (17). A multilayer tissue web according to claims 13-20, characterized in that at least one top layer is formed into a patterned intermediate bulk-giving spacer layer (7, 32). A multilayer tissue product according to any one of claims 13-21, characterized in that at least one layer comprises a basis weight pattern in the form of a watermark constituting a logo, a descriptive or representing pattern, signs, symbols and the like. A single-layer, multilayer tissue web according to claims 13-22, characterized in that the paper has at least three layers, of which two outer and at least one intermediate layer, at least one intermediate layer consisting of said patterned, discontinuous or bulk-giving layers. 'o - n o n »ovana v 25 A single-layer, multilayer tissue web according to claims 13-22, characterized in that the paper has at least three layers, of which two outer and at least one intermediate layer, at least one outer layer, have openings (30) which promote absorption of highly viscous liquids, at least one intermediate layer consists of a bulk-giving layer (32), which absorbs and stores liquid, and that at least one second outer layer has a smooth or rough surface (34).