MXPA01003315A - Method of producing a wetlaid thermobonded web-shaped fibrous material and material produced by the method - Google Patents

Abstract

Method of producing an impulse dried wetlaid fibrous web-shaped material, such as paper or nonwoven, having a three-dimensional pattern of alternating raised and recessed portions, which have been provided in connection with impulse drying, at which the wet fibrous web is passed through at least one press nip (12) comprising rotatable roll (13) which is heated and that the fibrous web during the passage through the press nip is given a three-dimensional pattern of alternating raised and recessed portions eitherby means of a patterned wire (11) and/or by a pattern on the heated roll (13). To the fibrous web there has been added a material that softens or melts in the temperature interval 100-400°C and that at least the parts of the fibrous web that is located closest to the raised portions of the heated roll (13) are heated to such a high temperature that said material softens or melts and by that provides an increased amount of bonding points in the fibrous web. There is further provided a thermobonded impulse dried material produced by the method.

Description

METHOD FOR PRODUCING A FIBROUS MATERIAL IN THE FORM OF THERMALLY APPLIED FABRIC IN THE WET AND MATERIAL STATE PRODUCED BY SUCH METHOD Technical Field The present invention relates to a method for the production of a material in the form of fibrous tissue applied in the wet state as, for example, For example, paper or a non-woven structure, having a three-dimensional pattern of alternately raised and recessed portions, said pattern has been provided in relation to pulsed drying, wherein the wet fibrous fabric is passed through at least one Press throttling comprising a heated heated rotating roller and the fibrous tissue during the passage through the pressing throttle receives a three-dimensional pattern of portions alternately raised and recessed either by means of a mesh having a pattern and / or by means of a pattern on the heated roller and where said pattern is pressed into the fibrous tissue against a opposite half. The invention also relates to a material in the form of tissue produced by the method. BACKGROUND OF THE INVENTION Wet paper fabrics are usually dried against one or more heated rollers. A commonly used method for making tissue-type paper is what is known as Yankee drying. During Yankee drying, the wet paper web is pressed against a Yankee cylinder heated by steam that can have a very large diameter. Additional heating is provided for drying by blowing heated air. If the paper to be produced is a soft paper, the paper fabric is usually subjected to creping against the Yankee cylinder. The drying against the Yankee cylinder is preceded by the removal of water in vacuum and a pressing in the humid state, where the water is mechanically expelled from the tissue by pressing. Another method of drying is what is known as air passage drying (TAD). In this method, the paper is dried through hot air blown through the wet paper fabric, often without wet pre-pressing. The paper fabric that penetrates the dryer by air passage is then only dehumidified in vacuum and has a dry content of about 25-30% and is dried in the hot air dryer until it reaches a dry content of about 65. -95%. The tissue paper is transferred to a special drying fabric and is passed over what is known as a TAD cylinder having an open structure. Hot air is blown through the paper tissue during its passage over the TAD cylinder. The paper produced in this way, mainly soft paper, becomes very soft and bulky. The method nevertheless requires a high energy consumption since all the water removed has to be evaporated. In relation to the TAD drying, the pattern structure of the drying fabric is transferred to the paper fabric. This structure is also essentially maintained in the wet condition of the paper since it has been provided to the wet paper fabric. A description of the TAD technique can be found, for example, in US-A-3, 301, 746. Pulsed drying of a paper form is disclosed, for example, in SE-B-423 118 and includes the passage of the tissue from wet paper through the press throttle between a press roll and a heated roll, which is heated to a temperature high enough for rapid and strong steam generation to occur at the interface between the wet paper tissue and the heated roll. The heating of the roller is achieved, for example, by means of gas burners or other heating devices, for example by means of electromagnetic induction. Due , to the fact that heat transfer to paper occurs mainly in a press throttle, an extraordinarily high heat transfer rate is obtained. All the water removed from the paper tissue during pulsed drying is not evaporated but the steam in its path through the paper fabric draws water from the pores between the fibers in the paper fabric. In this way the drying efficiency becomes very high.

EP-A-0 490 655 discloses the production of a paper fabric, especially soft paper, wherein the paper simultaneously with pulse drying receives a embossed surface. This embossing is effected by pressing a pattern on the paper from one side or both sides against a hard fastener. This provides compression to the paper and in this way a higher density is achieved in certain portions opposite the impressions and a lower density in the intermediate portions. In DE-A-26 15 889, a soft thermally bonded embossed paper is disclosed. Thermoplastic fibers are added to the paper fabric and after drying the paper tissue is heated to a temperature that exceeds the softening temperature of the thermoplastic fibers. Simultaneously with this heating the paper is embossed in the form of a pattern. Drying by air passage is mentioned as a drying method. OBJECT AND MOST IMPORTANT CHARACTERISTICS OF THE INVENTION The object of the present invention is to provide a method for producing a fibrous material in the form of pulse-dried fabric applied in the wet state, having a three-dimensional pattern, for example, a material for shaking or a soft paper whose purpose is to serve as sanitary paper, rolls for the kitchen, tissues, napkins for the table and the like, where the paper has a high volume, a high elasticity and is very soft. The structure of the material, for example, of the paper, must be maintained essentially also in the wet state. This has been achieved in accordance with the present invention by adding to the fibrous tissue a material that softens or melts in the temperature range of 100-400 ° C, and where the parts of the fibrous tissue that are located closest to the elevated portions of the heated roller are heated to a temperature such that said material softens or melts and thus provides an increased amount of binding points in the fibrous tissue. Due to the fact that drying, thermal bonding and pattern embossing are carried out in the same step - the impulse drying step - a more stable fiber structure with a low degree of internal fatigue is achieved, which occurs in another It easily forms if the fibrous tissue is dried and the fiber structure is blocked before thermal bonding. The invention also relates to a fibrous material in the form of pulse-dried fabric applied in the wet state, for example, paper, or non-woven structure, provided in a three-dimensional pattern with alternately raised and recessed portions, which have been provided in relation to to pulsed drying, wherein the fibrous tissue contains at least 5% by weight, calculated on the basis of the dry weight of the fibrous tissue, of a material that softens or melts within a temperature range of 100 to 400 ° C Additional features and advantages of the invention will be discussed in the following description and the appended claims. DESCRIPTION OF THE DRAWINGS The invention will be described in greater detail with reference to some embodiments illustrated in the accompanying drawings. Figures 1-4 are schematic side views of a pulse drying device in accordance with some different embodiments. Figure 5 is a schematic side view of a device for producing a fibrous tissue in the form of a foam, which is hydroentangled prior to pulse drying. DESCRIPTION OF THE INVENTION Figure 1 shows schematically a device for effecting pulsed drying of a paper tissue. The wet paper web 10 from which the water has been removed in suction boxes (not shown) is supported by a mesh or felt 11 and is brought to a press throttle 12 between two rotating rollers 13 and 14, wherein the roller 13 which is in contact with the paper web is a heating device 15 heated to a temperature high enough to provide drying of the paper web. The surface temperature of the heated roller may vary according to factors such as the moisture content of the paper tissue, the thickness of the paper web, the contact time between the paper web and the roller and the desired moisture content of the finished paper web. Obviously the temperature of the surface should not be so high as to damage the paper tissue. A suitable temperature should be within a range of 100 to 400 ° C, preferably 150 to 350 ° C and especially 200 to 350 ° C. The paper web is pressed against the heated roller 13 by means of the roller 14. The pressing device can obviously be designed in other ways. Two or more pressing devices can also be placed one after the other. The fastener 14 can also be a press shoe. It is also possible for the paper fabric 11 to pass into the pressing choke without support, ie without support by mesh or felt. A very rapid, violent and almost explosive generation of steam takes place at the interface between the heated roller 13 and the wet paper fabric, where steam generated in its path through the paper fabric draws water. For a further description of the pulsed drying technique reference is made to the aforementioned document SE-B-423 118 and for example to EP-A-0 337 973 and US-A-5, 556, 511. When drying, the paper is wound onto a recovery roller 16. If desired, the paper can be creped before winding. It is noted, however, that the need for paper creping to provide softness and volume which is the objective in the case of soft paper is reduced when a pulse drying method according to the invention is employed, since the paper is It provides volume and smoothness through the three-dimensional structure and the selected pattern. The paper is after drying rolled into a recovery roll 16. It is noted that the need for paper creping to provide softness and volume which is the purpose in the case of soft paper, is reduced when the pulse drying method is employed. according to the invention since the paper by means of the three-dimensional structure and the selected pattern acquires volume and softness. The paper tissue can, before its penetration into the pulse drier, either lose water in suction boxes or it can also be slightly pressed. Simultaneously with impulse drying, the paper receives a three-dimensional structure. This can be achieved as shown in Figure 1 by the fact that the heated roller 13 is equipped with an embossing pattern consisting of alternately raised and lowered areas. This structure is substantially maintained also in a wet back condition of the paper, since it is provided to the wet paper web in relation to its drying. Since the term embossing is normally used for a form that is achieved on dried paper, we have used the term "press molding" for the three-dimensional formation of paper that occurs simultaneously with pulsed drying. By this pressing molding, the volume and the absorption capacity of the paper are increased, and these are important qualities for a soft paper. The paper fabric can be pressed against a non-rigid surface, ie a compressible pressing felt 11. The roller 14 can also have an elastically yielding surface, for example, a rubber wrapping surface. In this way, the paper is provided with a three-dimensional structure whose total thickness is greater than the thickness of the unpressed paper. In this way the paper is given a high volume and thus a high absorption capacity and a greater softness. In addition, the paper will have an elastic characteristic. At the same time, a density that varies locally is obtained on paper. The paper can also be pressed against a hard surface, for example, a mesh 11 and / or a roller 14 having a hard surface, wherein the pattern of the heated roll 13 is pressed into the paper fabric under strong compression of the paper on the opposite side of the prints, while the intermediate portions are maintained without compression. The embodiment illustrated in figure 2 differs from the embodiment illustrated in figure 1 by the fact that below the mesh 11 a felt 17 is placed extending around the roller 14. The function of the felt 17 is to improve the effect of removal of the felt. water and extend the pressing throttle. According to the embodiment illustrated in FIG. 3, the paper web 10, during drying, is supported by a mesh 11 having a pattern, which is pressed into the tissue of the paper when it passes through the press throttle. between the rollers 13 and 14. The roller 13 can be either smooth, as shown in Figure 3, or it can have an embossed pattern. If the roller 13 is smooth, the pressed-molded paper will have a smooth surface and an impressed surface. In the case in which the roller 13 has an embossed pattern that will also be printed on the paper, so it will have one side with a pattern corresponding to the structure of the mesh 11 and on the opposite side it will have a pattern corresponding to the embossing pattern of the roller. The patterns may coincide but it is not necessary and / or they may be the same or different. In accordance with the embodiment illustrated in Figure 4, the three-dimensional pattern in the paper fabric is produced by a pattern band 11 which extends around the cylinder 13 and is heated by said cylinder. The pattern of the web 11 is molded by pressing on the paper web as said web passes through the press throttle 12 between the rollers 13 and 14. The paper web is supported by a felt 17 through the press throttle. According to the invention, a material is added to the paper fabric, said material softens or melts in the temperature range of 100 to 400 ° C. Said material can be synthetic or natural polymers in the presence of softeners. The material may be in the form of powders, flakes, fibers, continuous filaments, or an aqueous suspension, for example, a latex dispersion. Examples of thermoplastic polymers are polyolefins such as polyethylene and propylene, polyesters, polyamides, polylactics, conjugated fibers, etc. The material can be added in the papermaking process together with the pulp fibers before the formation and removal of water from the paper tissue. It can also be added in the form of a suspension flowing in the formation mesh through a separate container placed either before or after the container for the pulp suspension. Alternatively, the material may have the form of a suspension to be added through a certain section of a multi-layer container and wherein the pulp suspension is added through the other sections of the multi-layer container. It is also possible to add the material to the paper tissue formed in the form of a liquid suspension through spraying or through contact with a rotating transfer roller. The material can be added either to the entire paper web or only to portions of the paper web intended to be closer to the heated roller 13 especially near the raised portions of said roller. By mixing the material with the pulp fibers before the pulp container a substantially homogeneous mixture of the material in the whole paper tissue is achieved. However, if the material is added through a separate container or through a special multi-layer container section or alternatively sprayed or printed on the already formed paper tissue, the material will be located mainly in a certain layer of the paper fabric, preferably in the layer that is located closest to the heated roller 13 during pulsed drying. If the material is printed on the paper tissue formed by a transfer roller, it is possible for the material to be printed in a pattern that essentially corresponds to the pattern of the heated roll 13 in the form of raised and lowered portions, such that the paper fabric contains the softening or melting material only in the portions that will be in contact with the raised portions of the roller 13. By adding to the paper fabric of said material, which is softened or melted, an increased amount of binding sites is achieved in the paper fabric. In this way, the variation of base weight and the three-dimensional structure that has been provided to the paper web in relation to the impulse drying combined with the press molding becomes effectively permanent. This structure is also maintained in the wet condition of the paper. A further advantage of the invention is that the drying, thermal bonding and pattern embossing that take place in the same step - the pulse drying step - where a more stable paper structure with a low degree of internal fatigue is achieved, which occurs of another easily if the paper is dried and the fibrous structure is blocked before the thermal bonding. In the embodiment illustrated in Figure 5, the thermoplastic material consists of continuous filaments 20, such as spun or melted fibers that are formed through melting or spinning equipment 21 and are applied on a mesh 22 where they form a structure fibrous, open where the fibers are relatively free between them. This is achieved either by the fact that the distance between the meltblown / spinneret nozzle and the mesh is relatively large, such that the fibers will have time to cool before reaching the mesh 22, and thus will reduces its adhesion capacity. Alternatively, the cooling of meltblown / spunbond fibers before their application to the mesh is provided differently, for example, by spraying with liquid. On top of the melted / spun layer a fibrous fabric 25 formed in foam from a pulp container 24 is applied. Foaming means that a fiber fabric is formed from a dispersion of pulp fibers in a Foamy liquid containing water and a surfactant. The foaming technique is disclosed, for example, in GB 1,329,409, US 44,443,297 and WO 96/02701. A fiber fabric formed in foam has a very uniform fiber formation. For a more detailed description of the foaming technique reference is made to the aforementioned documents. Through the effect of intense foam formation, a mixture of the meltblown / spun fibers in the foam fiber dispersion is already obtained during this step. Air bubbles from the intense turbulent foam from the container 24 penetrate the mobile meltblown fibers and separate them, so that relatively thicker fibers are integrated with the meltblown fibers. After this step, an integrated fiber fabric will be obtained, and layers of different fiber fabrics will no longer be obtained. In addition to the pulp fibers, the fiber fabric formed into foam may also contain fibers of other types, both synthetic and natural fibers. The foam is sucked through the mesh 22 and the fiber fabric of the melt blown / spun fibers applied to the mesh, through suction boxes (not shown) placed under the mesh. The integrated fiber fabric of meltblown / spunbond fibers and other fibers are then hydroentangled while the fabric is still supported by the mesh 22 and thus form a composite material. Optionally, the fiber fabric can, prior to hydroentanglement, be transferred to a special entanglement mesh. The entanglement station 25 comprises several rows of nozzles from which very fine water jets emerge under very high pressure and are directed against the fiber fabrics and provide the entanglement of the fibers.

For a further description of the hydroentanglement technique which is also known as spun lace technique, reference is made for example to CA Patent 841,938. The meltblown / spunbond fibers, prior to thermal shrinkage, are blended and integrated with the fibers in the fiber fabric formed into foam due to the foaming effect. During the subsequent hydroentanglement, a tangle of the different types of fibers is obtained and a composite material is provided in which all types of fibers are mixed in an essentially homogeneous manner and integrated among them. The thin mobile melt blown fibers are easily twisted and entangled with the other fibers which provides a high strength material. The energy supply required in the hydroentanglement stage is relatively low, that is, it is easy to entangle the material. The power supply in the hydroentanglement stage is preferably within a range of 50 to 300 kWh / ton. After the hydroentanglement, the paper web is impulse-dried and press-molded in a manner corresponding to that disclosed above. The cross-tie step can, however, be eliminated, and pulsed drying is effected directly after draining the fiber fabric formed into foam. The hydroentanglement contributes to an essentially improved wet strength due to the fact that the fibers are entangled therebetween. This improved resistance in wet state is especially desired in the case of applications where the material must be used as cleaning material. However, the high wet strength that is provided to the material through the fabric is sufficient for many applications. Alternative embodiments of the method described above relate to the use of a preformed fabric layer or the like on which the blown / melt / spun fibers are applied 20 after which the fiber fabric 23 formed in foam is applied over the top of melt blown / spun fibers. A layer of meltblown / spunblown fibers can also be placed between two foam-formed paper tissues. The paper can be produced by numerous different types of pulp. If the recovery pulp is not taken into account, which is used today largely to be used mainly for toilet paper and kitchen rolls, the type of pulp most frequently used for soft paper is chemical pulp. The lignin content in said pulp is practically zero and the fibers, which consist mainly of pure cellulose, are relatively thin and flexible. The chemical pulp is a pulp of low yield since it offers a yield of only approximately 50% calculated on the basis of the wood raw material used. Therefore it is a relatively expensive pulp. Therefore, it is common to use more economical pulps that are known as high performance pulps, for example, mechanical pulp, thermomechanical pulp, chemomechanical pulp (CMP) or chemithermomechanical pulp (CTM?) On soft paper as well as other types of paper, For example, newspaper, cardboard, etc. In high performance pulps, the fibers are thicker and contain a high amount of lignin, resins and hemicellulose. Lignin and resins provide the fibers with more hydrophobic properties and a reduced ability to form hydrogen bonds. The addition of a certain amount of chemithermomechanical pulp in soft paper has, due to the fiber-reduced fiber bond, a positive effect on properties such as volume and absorption capacity. A special variant of a chemithermomechanical pulp (CTMP) is what is known as a high temperature chemithermomechanical pulp (HT-CTMP), whose production differs from conventional CTMP production mainly by the use of a higher temperature for impregnation , preheating and refining, preferably not less than 140 ° C. For a more detailed description of the production method for HT-CTMP, reference is made to WO 95/34711. The characterization for HT-CTMP is that it is a high-yield pulp of long fibers, which presents high volume and from which the water can be easily removed, with a low content of lumps and a low content of fines. In accordance with the present invention it has been found that the high performance pulp is especially suitable for pulse drying since it is not sensitive to pressure, it is easy to remove the water and has an open structure that allows the generated steam to pass through through it. This minimizes the risk of overheating of the paper and destruction of the paper during pulsed drying, which is carried out at considerably higher temperatures than in other drying methods. The insensitivity to pressure and open structure depends on the fact that the fibers in the high-performance pulp are relatively thick and rigid compared to the fibers in the chemical pulp.

Pulsed drying is also carried out at a considerably higher temperature, for example than Yankee drying or air-pass drying, to which, according to a theory to which the invention is not limited, the softening point of The lignin present in the high-performance pulp is achieved during pulse drying and simultaneous pressing molding. When the paper cools, the lignin hardens again and contributes to make the three-dimensional structure provided to the paper permanent. This is therefore maintained essentially also in the wet condition of the paper, which significantly improves the volume and the absorption capacity of the paper. According to one embodiment of the invention, the paper contains a certain amount of a high-yielding pulp, said amount must be at least 10% by weight calculated based on the dry weight of fibers, preferably at least 30% by weight. weight, and especially at least 50% by weight. Mixing a certain amount of another pulp with high strength properties such as chemical pulp, preferably long-fiber kraft pulp, or recycled pulp, is an advantage if high paper strength is desired. The invention, however, is not limited to the use of a certain type of pulp in the paper, but can be applied to any type of optional pulp or optional pulp mixture. In all cases it is also possible to allow the wet paper fabric to pass through at least two consecutive press throttles 12 each comprising a rotating roller 13 which is heated and provided with a pattern of alternately raised and recessed portions for pressing in the tissue of paper against a fastener. The second pressing throttling in this case is preferably reversed compared to the first pressing throttling, where one side of the paper fabric reaches the highest temperature in the first pressing throttling while the other side reaches the highest temperature in the second pressing throttle. According to a further embodiment of the invention, the paper fabric has a composition of variable material as can be seen in its thickness direction such that, at least in the layer (s) it will be (n) ) closer to the heated roller 13 in relation to pulsed drying, it contains a certain amount of material that softens, melts or hardens in the temperature range of 100-400 ° C. In this way the paper will receive a surface layer that contributes to strengthening of structural stability of paper also in a damp condition. The pulp composition in the rest of the layers of the paper can on the other hand be selected to optimize the other properties such as softness, strength, volume and coating. Common additives such as wet strength agents, softening agents, fillers, etc., can obviously also be used on paper. The paper fabric can after pulsed drying be subjected to different types of treatments known per se such as addition of different chemical agents, additional embossing, lamination, etc. It is also possible when transferring the paper fabric between two different meshes, for example, from a water removal mesh to a drying mesh, to have a difference in speeds between the meshes in such a way that the displacement of the paper tissue is slower in relation to the transfer. The paper tissue will then be compacted to a certain extent which further increases the softness. The material in the form of a fabric has been called in the above description paper for simplification purposes. If other fibers other than pulp fibers are mixed in the material, the term "non-woven structure" would be a more precise term and is obviously included in the invention.

Claims (1)

1. CLAIMS A method for producing a material in the form of fibrous tissue applied in the wet state, such as paper or a non-woven structure, having a three-dimensional pattern of alternately raised and recessed portions, which has been provided in relation to drying by impulses through which the wet fibrous tissue (10) is passed by means of at least one pressing throttle (12) comprising a heated rotating roller (13) and the fibrous tissue during the passage through the pressing throttle receives a three-dimensional pattern of alternately raised and recessed portions, either by means of a mesh having a pattern (11) and / or through a pattern on the heated roll (13) and wherein said pattern is pressed into the fibrous tissue against an opposite device, characterized by the addition to the fibrous tissue (10) of a material that softens or melts in the temperature range of 100 to 400 ° C and where at least the portions of the fibrous tissue closest to the raised portions of the heated roller (13) are heated to said high temperature in such a way that the material softens or melts and thus an increased amount of binding points is provided. in the fibrous tissue. A method according to claim 1, characterized in that said material comprises synthetic or natural polymers with thermoplastic properties, chemically modified lignin and / or synthetic or natural polymers together with softeners. A method according to claim 1 or according to claim 2, characterized in that said material is in the form of powder, flakes, fibers or an aqueous suspension such as, for example, a latex suspension. A method according to any of the preceding claims, characterized in that said material is in the form of continuous filaments. A method according to claim 4, characterized in that the continuous filaments (20) are meltblown and / or spun fibers. A method according to any of the preceding claims, characterized in that the fibrous tissue is formed into foam. A method according to any of claims 4 to 6, characterized in that it includes the foaming of a fibrous fabric and the mixing of the dispersion of foam fibers (23) with the continuous filaments (20), and pulsed drying. of drained fibrous tissue. A method according to claim 7, characterized in that it has a hydroentanglement of the dispersion of fibers in foam and continuous filaments. The method according to any of claims 1-3, characterized in that said material is added to the fiber dispersion prior to the formation and removal of water from the fibrous tissue. A method according to any of claims 1-3, characterized in that said material is added to the fibrous tissue in the form of a suspension that is applied on the forming mesh through a separate container. A method according to any of claims 1-3, characterized in that said material in the form of a suspension is added through at least one separate section in a multi-layer container and wherein the other fiber dispersion is added to through other sections of the multi-layer container. A method according to any of claims 1-3, characterized in that said material is added to the fibrous tissue formed in the form of a liquid suspension by spraying or by contact with a rotating transfer roller. 3. A method according to any of the preceding claims, characterized in that said material is added to the fibrous tissue only in the portions provided to be closer to the heated roller (13), especially near the elevated portions of said roller. 14. A method according to any of the preceding claims, characterized in that the • opposite means (11, 14) is equipped with a non-rigid surface such that the paper fabric receives a three-dimensional structure having a total thickness greater than the thickness of the unpressed paper web. 15. A method according to claim 14, characterized in that the fibrous tissue is supported by a compressible pressing felt (11) through the pressing throttle (12), said pressing felt forming said opposite non-rigid means. 16. A method according to claim 14, characterized in that the pressing felt (11) is pressed against a resilient surface. (14) in the pressing choke (12). A method according to any of the preceding claims, characterized in that the pulp fibers included in the fibrous tissue contain at least 10% by weight, preferably at least 30% by weight and more preferably 50% by weight , calculated on the basis of the weight of dry fibers, of a 5 high-performance pulp, such as mechanical pulp, thermomechanical pulp (TMP) or chemithermomechanical pulp (CTMP). 18. A method of conformance with any of the preceding claims, characterized in that 10 adds a wet strength agent to the fiber dispersion or fibrous tissue prior to pulsed drying. V. 19. A material formed in fibrous tissue applied in a pulsed, dried state, such as, for example, Paper or a non-woven structure, having a three-dimensional pattern of alternately raised and recessed portions, which has been provided in relation to pulsed drying, characterized in that the fibrous fabric contains at least 5% by weight, 20 calculated on the basis of the dry weight of the fibrous tissue, of a material that softens or melts in the temperature range of 100 to 400 ° C. 20. A fibrous material in the form of fabric according to claim 19, characterized because the The thermoplastic material comprises synthetic or natural polymers with thermoplastic properties, chemically modified lignin and / or synthetic or natural polymers together with softeners.