Paper machine clothing fabric

Abstract

Paper machine covering fabric for a fiber web forming and / or converting machine, wherein the fabric comprises a first side and a second side opposite the first side, a machine direction and a machine cross direction, and several machine direction yarns interwoven with several machine cross direction yarns to form a repeating weave pattern on the first side, wherein in each pattern repeat a machine direction yarn forms numerous successive MD floats in the machine direction on the first side, wherein an MD float is formed by passing a machine direction yarn on the first side over several adjacent machine cross direction yarns, wherein the weave pattern comprises several compression areas separated from each other by recesses set back from the compression areas.wherein a compression zone is formed by several MD floats arranged adjacent to each other in the machine transverse direction, wherein the MD floats forming a compression zone overlap at least partially in the machine direction, wherein at least a majority of these MD floats are offset from each other in the machine direction, characterized in that at least one compression zone has at least a first group of MD floats and at least a second group of MD floats, wherein the at least one first group is formed by a first number of adjacent MD floats, and the at least one second group is formed by a second number of adjacent MD floats, and wherein the average offset of the MD floats in the at least one first group is smaller than the average offset of the MD floats in the at least one second group.

Description

Technical field

[0001] The present invention relates to a paper machine clothing fabric for use in the production of a fibrous web, such as a paper, cardboard, tissue, or nonwoven web. The present invention particularly relates to a paper machine clothing fabric used for producing structured tissue papers or nonwoven webs for hygiene or wipe products.

[0002] Tissue paper is a soft, absorbent paper (softer than graphic paper or cardboard and with a higher tensile strength index than graphic paper or cardboard, see DIN EN 12625-4 and DIN EN 12625-5) with a base weight of 8 to 40 g / m² 2 , preferably 10 to 25 g / m² 2 per layer. Tissue paper can essentially be made from natural fibers such as cellulose fibers.

[0003] The term nonwoven web (ISO 9092, DIN EN 29092) applies to a wide range of products whose properties lie between those of paper (cf. DIN 6730, May 1996) and cardboard (DIN 6730) on the one hand, and textiles on the other. A nonwoven web can be made primarily of natural fibers, synthetic fibers, or a mixture thereof.

[0004] Tissue paper or nonwoven webs for hygiene or wiping products, in particular, require a structure that provides voluminous areas with lower density and high liquid absorption capacity, as well as less voluminous areas with higher density and good tensile strength.

[0005] To produce such structured fibrous webs, paper machine covering fabrics (so-called structural fabrics) with a paper contact area featuring raised compression areas and troughs that separate the compression areas and are set back from the compression areas are used to give the tissue paper or nonwoven web a structure with voluminous areas of high absorbency and compressed areas of high tensile strength.

[0006] To produce such structured fiber webs, it is possible to form the web from a fiber suspension on such a structured fabric, or to form the voluminous and high-strength areas by forming or converting an already formed fiber web on such a structured fabric. State of the art

[0007] US 6,039,838 A describes a structured fabric with multiple continuous compression zones extending in the machine direction and separated by troughs. EP 1,916,332 A1 describes a similar structure. According to EP 1,916,332 A1, the compression zones are formed by floats of machine-direction yarns (hereinafter referred to as MD floats) that are grouped together and consistently offset from one another. The web or paper processed on these fabrics exhibits voluminous areas and compressed areas of substantially constant width. This results in a tissue paper or nonwoven web with high tensile strength in the machine direction but low tensile strength in the machine transverse direction.

[0008] In addition, the visual appearance, which is an important feature for consumer recognition of hygiene or wipe-on products, is very similar to that of many existing tissue papers or nonwovens when using fibrous webs produced on a fabric as shown in US 6,039,838 A. Therefore, it is difficult to successfully establish a market position for a new hygiene or wipe-on product produced on a fabric according to US 6,039,838 A.

[0009] US 7,585,393 B2 discloses a structured fabric with a weave pattern featuring square compression zones that are offset and adjacent in the machine and machine transverse directions. Due to the relatively short compression zones in the machine direction, tissue paper or nonwoven webs produced on such a fabric exhibit relatively low tensile strength and low bulk.

[0010] For the sake of completeness, reference should also be made to the publications US 4 191 609 A and US 2012 / 0 024 486 A1.

[0011] There is a need for an improved paper machine covering fabric with good tensile strength combined in the machine direction and better cross-linked in the machine transverse direction. Description of the invention

[0012] Based on the above, the present invention is based on the objective of providing a paper machine covering fabric for the production of tissue paper or nonwoven webs with improved tensile strength in the machine and machine transverse directions.

[0013] This task is accomplished with a paper machine covering fabric as defined in claim 1, claim 37 and claim 45.

[0014] According to a first aspect of the present invention, a paper machine cloth is provided comprising a first side and a second side opposite the first side, a machine direction, and a machine transverse direction. For clarification: The term "machine direction" refers to the direction in which the cloth moves during the papermaking process. The term "machine transverse direction" refers to the direction perpendicular to the machine direction. It should also be noted that the terms "cloth" and "paper machine cloth" are used synonymously. The cloth further comprises several machine direction yarns interwoven with several machine transverse yarns to form a repeating woven pattern on the first side. The longitudinal extent of the "machine direction yarns" runs essentially in the machine direction, i.e.,that their longitudinal extent may deviate by a maximum of + / - 30° from the machine direction of the fabric. The longitudinal extent of the "machine cross-direction yarns" runs essentially in the machine cross-direction, i.e., that their longitudinal extent may deviate by a maximum of + / - 30° from the machine cross-direction of the fabric. The "pattern repeat" is the smallest unit of the woven pattern in the machine and machine cross-directions. The woven pattern is formed by repeating or duplicating the pattern repeat. In the pattern repeat, a machine direction yarn forms numerous machine direction floats (hereinafter referred to as MD floats) on the first side, which are consecutive in the machine direction. An MD float of a machine direction yarn is formed by passing the respective machine direction yarn over several adjacent machine cross-direction yarns on the first side. If yarns of a type, i.e.,Machine directional yarns or machine transverse directional yarns are adjacent yarns, provided no other yarn of the same type is arranged between them. Between two successive MD floats of a machine directional yarn, the machine directional yarn forms at least one offset and / or one float on the second side.

[0015] The term "float" is used here when a yarn of one type (machine directional or machine cross-directional yarn) is passed over at least two adjacent yarns of the other yarn type (machine cross-directional or machine directional yarn) on one side of the fabric. For example, if a machine directional yarn is passed over two adjacent machine cross-directional yarns on the first side, this forms an MD float over two machine cross-directional yarns on the first side. In contrast to the term "float," the term "crank" is used when a yarn of one type is passed over only one yarn of the other type on one side of the fabric.Each MD floatation begins with a first of the adjacent machine cross-directional yarns, with the machine directional yarn being transferred from the second side to the first side, and ends with a last of the adjacent machine cross-directional yarns, with the machine directional yarn being transferred on the first side before it disappears towards the second side.

[0016] The pattern repeat further comprises several compression zones. Each compression zone is formed by several MD floats arranged adjacent to each other in the machine transverse direction. The adjacent MD floats forming the respective compression zone overlap at least partially in the machine direction, with at least a majority of these MD floats being offset from each other in the machine direction such that the compression zone extends diagonally (at an angle) to the machine and machine transverse directions along its length. If two MD floats (formed on the first side of the fabric) are arranged adjacent to each other in the machine transverse direction, they are formed by two adjacent machine-direction yarns.

[0017] The term “majority” means that more than 50%, preferably at least 75%, particularly preferably at least 85% of the adjacent MD floats forming the respective compression area are offset from each other.

[0018] Two adjacent MD floats are "offset" from each other if their "centers" are shifted relative to each other in the machine direction. The "center" of an MD float is half the length of that float. The "length" of an MD float, or "float length," is determined by the number of adjacent machine cross-direction yarns over which the machine direction yarn is guided on the first side when forming the MD float.

[0019] The compression zones are separated by troughs that are set back from the compression zones on the first side. It should be noted that, with regard to the finished paper or nonwoven web produced on the paper machine cloth, those areas of the web that have been in contact with the compression zones will be compressed and / or have a lower base weight than those areas of the web that have been in contact with the troughs.

[0020] The first aspect of the invention is characterized in that at least one compression area has at least one first group of MD floats and at least one second group of MD floats, wherein the at least one first group is formed by a first number of adjacent MD floats, and the at least one second group is formed by a second number of adjacent MD floats, and wherein the average offset of the MD floats in the at least one first group is smaller than the average offset of the MD floats in the at least one second group.

[0021] The “average offset” of a group is calculated by adding up all the offsets between the adjacent MD floats forming the respective group and dividing by the number of offsets in the group.

[0022] For example, if a group consists of seven (7) MD floats, the group has six (6) offsets (offset from the 1st to the 2nd MD float, offset from the 2nd to the 3rd MD float, offset from the 3rd to the 4th MD float, offset from the 4th to the 5th MD float, offset from the 5th to the 6th MD float, and offset from the 6th to the 7th MD float). If, in this example, the offset for all adjacent MD floats is 1 (offset from the 1st to the 2nd MD float equals 1, offset from the 2nd to the 3rd MD float equals 1, ..., offset from the 6th to the 7th MD float equals 1), the average offset is one (1). If, in the above example, the offset between the 2nd and 3rd MD floats is three (3) and all other offsets are equal as described above, then the average offset would be one point three three (1.33).

[0023] By providing at least one compression zone with a first and a second group of MD floats, where the MD floats forming the first group have a smaller average offset than those forming the second group, the compression zone can have a wavy outer contour with variable width. In contrast to compression zones along straight lines, this results in a more uneven arrangement of the high-volume and high-strength areas in the tissue paper or nonwoven web produced on such a fabric. Therefore, a fiber web with improved tensile strength is provided in both the machine and machine transverse directions.Because the compressed areas of the fiber web produced on a fabric according to the invention extend in an arc-like series, the transition zone between an uncompressed, high-volume area and a compressed, high-strength area is much longer compared to a straight transition zone. Thus, a tensile force acting on the fiber web is distributed over a longer path.

[0024] This leads to the benefit that such transition zones are less weak compared to paper produced on state-of-the-art fabrics.

[0025] Preferably, the majority of the compression areas, and particularly preferably each compression area, comprises at least a first and a second group of MD floats.

[0026] The average offset of the MD floats in the at least one first group can be between 0 and 2.5, preferably between 0.5 and 2. Furthermore, the average offset of the MD floats in the at least one second group can be between 1.2 and 4.

[0027] The offset of the adjacent MD floats in the at least one first group can be such that the adjacent MD floats overlap in the machine direction by at least half their float length. Preferably, at least 50%, and more preferably at least 75%, of all adjacent MD floats forming a compression zone have an overlap of at least three successive machine transverse yarns.

[0028] According to a preferred embodiment of the first aspect, the second number can be smaller than the first, meaning that the second group with the larger average offset is formed by fewer MD floats than the first group. It is possible that a majority of compression zones are formed by at least 10 adjacent MD floats. Furthermore, it is possible that all MD floats forming a compression zone are offset from each other in the machine direction.

[0029] More specifically, it is possible that each of the first groups is formed by at least four adjacent MD floats, preferably by at least six adjacent MD floats, and / or that each of the second groups is formed by at most eight adjacent MD floats, preferably by at most six adjacent MD floats.

[0030] For example, the first groups can consist of between 4 and 20 adjacent MD floats, preferably between 6 and 15 adjacent MD floats. It is also possible for the second groups to consist of between 2 and 10 adjacent MD floats, preferably between 3 and 6 adjacent MD floats.

[0031] The first and second groups can be arranged alternately. In this context, "alternatingly" means that a second group is positioned between two adjacent first groups, and vice versa. The first and second groups can also be consecutive. In this context, "consecutive" means that an MD fleet, which does not belong to either of these groups, can be positioned between a first and a second group.

[0032] The compression areas are preferably arranged adjacent to each other in the machine direction and / or the machine transverse direction, with a trough separating them being arranged between two adjacent compression areas.

[0033] The compression zones can provide at least one continuous compression zone and / or at least one non-continuous compression zone.

[0034] The width of each continuous compression area is preferably less than half, more preferably less than one third (1 / 3), and most preferably less than one fifth (1 / 5) of the width of the pattern repeat.

[0035] A continuous compression area can have a length that extends at least as far as the length of a pattern repeat without being interrupted by a trough. The "length of a compression area" can be the greatest extent that the compression area has along a straight line selected from all possible straight lines in the plane of the machine and machine transverse directions. The "width of a compression area" can be the greatest extent that the compression area has between any two adjacent troughs along a straight line in the plane of the machine and machine transverse directions that is perpendicular to the line defining the length. The "length of the pattern repeat" is the extent of the pattern repeat in the machine direction. The "width of the pattern repeat" is the extent of the pattern repeat in the machine transverse direction.Two continuous compression zones, arranged adjacent to each other in the machine transverse direction, can be separated by troughs. The continuous compression zones preferably extend in such a way that, when considering numerous adjacent pattern repeats, the continuous compression zone extends over the length or width of the fabric. Thus, the paper machine cloth has a network of compression zones and troughs that continuously overlap the entire cloth in an arc-like or wave-like pattern. This gives the fiber web produced with such a cloth a balanced distribution of voluminous areas with high absorption capacity and compressed areas with high tensile strength in both the machine direction and the machine transverse direction.The continuous compression zones spanning the length of the fabric also offer the advantage that the fiber web is consistently supported during a crepe step. This results in improved crepe behavior in terms of bulk.

[0036] A non-continuous compression area can be surrounded by a trough that separates the non-continuous compression area from the adjacent compression areas on all sides.

[0037] Preferably, the first and second groups of MD floats contribute to the formation of at least one continuous compression zone. In other words, at least one compression zone comprises at least one first group of MD floats and at least one second group of MD floats. Particularly preferably, more than 50%, and preferably more than 70%, of the MD floats forming the at least one continuous compression zone are arranged in the first or the second group. The continuous compression zones can be formed by at least 10 adjacent MD floats.

[0038] The at least one non-continuous compression zone can be formed by a number of MD floats arranged adjacent to each other in the transverse direction of the machine and offset from one another in the machine direction. Preferably, the number of MD floats forming the at least one continuous compression zone can be greater than the number of MD floats forming the at least one non-continuous compression zone. It is possible that the number of MD floats forming the at least one non-continuous compression zone is less than half, preferably less than one-third, of the number of MD floats forming the at least one continuous compression zone. Specifically, the at least one non-continuous compression zone can be formed by no more than six MD floats, preferably no more than four MD floats.The average length of the MD floats and / or the maximum length of the MD floats and / or the length of each MD float forming at least one non-continuous compression area may be less than the first and / or the second float length. The term "average float length" is calculated by summing the float lengths of all MD floats forming the respective non-continuous compression area and dividing by the number of MD floats forming the non-continuous compression area.

[0039] The outer contour of the continuous compression areas can be wavy. Viewed in the transverse direction of the machine, the fabric can furthermore have between 1 and 10, preferably between 3 and 8, continuous compression areas per pattern repeat.

[0040] The MD floats forming a first group may have a first average float length, and the MD floats forming the second group may have a second average float length, wherein the individual length of the MD floats forming the first group does not deviate from the first average float length by more than 25% and / or the individual length of the MD floats forming the second group does not deviate from the second average float length by more than 25%.

[0041] According to a further preferred embodiment of the first aspect of the present invention, the first groups can be formed by first MD floats and the second groups by second MD floats, wherein the first MD floats have a first float length and the second MD floats have a second float length, and wherein the first float length is different from the second float length. Depending on the specific requirements of the paper machine clothing fabric, it may be advantageous for the first float length to be greater than the second float length.

[0042] According to a specific example, a first group may consist of six (6) MD floats with a float length of seven (7), and a second group may consist of four (4) MD floats with a float length of five (5).

[0043] Alternatively, the first float length may be less than the second float length. According to a specific example of this embodiment, a first group may consist of five (5) MD floats with a float length of five (5), and a second group may consist of three (3) MD floats with a float length of seven (7).

[0044] According to a further preferred embodiment, the pattern repeat can comprise at least one machine direction yarn forming several successive first MD floats in the machine direction, and at least one further machine direction yarn forming several successive second MD floats in the machine direction. Two successive first MD floats in the machine direction can be separated by a further MD float, which is not a first MD float. Two successive second MD floats in the machine direction can be separated by a further MD float, which is not a second MD float.

[0045] More specifically, the pattern repeat can comprise several first machine direction yarns, each of which can form several first MD floats adjacent in the machine direction, and / or the pattern repeat can comprise several second machine direction yarns, each of which forms several second MD floats adjacent in the machine direction. Two first MD floats are adjacent in the machine direction if no further MD float is arranged between them, preferably if neither a further MD float nor a float on the second side is arranged between them. Two second MD floats are adjacent in the machine direction if no further MD float is arranged between them, preferably if neither a further MD float nor a float on the second side is arranged between them.

[0046] Additionally or alternatively, the pattern repeat can have several third machine direction yarns, with each third machine direction yarn forming at least one first and at least one second MD float consecutively in the machine direction.

[0047] The successive or adjacent MD floats of each machine directional yarn can be separated by a separation zone, which can each be formed by at least one offset and / or float of the machine directional yarn on the second side.

[0048] More specifically, at least some of the separation zones can be formed by i) a plain weave sequence of a machine directional yarn with at least three adjacent machine transverse directional yarns, or ii) a float of a machine directional yarn on the second side over at least two adjacent machine transverse directional yarns, or iii) a crank of a machine directional yarn on the second side over a machine transverse directional yarn, and iv) two successive cranks of a machine directional yarn on the second side over a machine transverse directional yarn, separated from each other by a float of the machine directional yarn over at most four adjacent machine transverse directional yarns on the first side.

[0049] Preferably, the length of the MD float of a separation zone according to iv) is less than or equal to the minimum float length of the MD floats forming the adjacent compression area(s).

[0050] The separation zones of all machine-direction yarns combined can contribute to or form the recessed troughs. Either the separation zones of adjacent machine-direction yarns overlap in the machine direction, or these separation zones are arranged adjacent to each other in the machine direction.

[0051] According to a further preferred embodiment of the first aspect of the present invention, a center-connecting line, which connects the centers of all adjacent MD floats forming the respective compression area, runs substantially at an angle to the machine direction and the machine transverse direction. To provide continuous areas that run substantially in the machine direction, the center-connecting line runs substantially in the machine direction.

[0052] The center-to-center line cannot be straight and preferably has at least two bends. Furthermore, the center-to-center lines of all continuous compression zones can run parallel to each other.

[0053] According to a second aspect of the present invention, a paper machine covering fabric is characterized, in addition to the features of the preamble of claim 1, in that at least one of the compression areas each of the MD floats has a float center point, wherein a first center line connecting the centers of first two adjacent MD floats extends at a first angle to the machine direction, and a second center line connecting the centers of second two adjacent MD floats extends at a second angle to the machine direction, wherein the second angle is different from the first angle.

[0054] It should be noted that the aforementioned center-connecting line of a respective compression area is formed by all center lines of the MD floats forming the compression area.

[0055] Preferably, a line connecting the centers of more than five adjacent MD floats is not straight and preferably has at least two bend points.

[0056] According to a third aspect of the present invention, a paper machine covering fabric is provided for a fiber web forming and / or converting machine, wherein the fabric has a first side and a second side opposite the first side, a machine direction and a machine transverse direction, as well as several machine direction yarns which are interwoven with several machine transverse direction yarns to form a pattern repeat on the first side.For each pattern repeat, a machine-directional yarn forms numerous MD floats in the machine direction, successive in the machine direction and separated from each other by separation zones. Each MD float is formed by passing a machine-directional yarn over several adjacent machine-transverse yarns on the first side, and each separation zone is formed by at least one float of the machine-directional yarn over at least one machine-transverse yarn on the second side. The fabric according to the third aspect is characterized in that the pattern repeat comprises several first machine-directional yarns and several second machine-directional yarns. The first machine-directional yarns form first MD floats separated by first separation zones, and the second machine-directional yarns form second MD floats separated by second separation zones.The first MD floats have a greater float length in the machine direction than the float length of the second MD floats. The first separation zones are shorter in the machine direction than the second separation zones, with at least some, preferably all, of the separation zones being formed by a plain weave sequence of the machine direction yarn with at least three successive machine cross direction yarns.

[0057] According to a preferred embodiment of the third aspect, the first machine direction yarns per pattern repeat form at least one, preferably several group(s) of adjacent first machine direction yarns, and / or the second machine direction yarns form at least one, preferably several group(s) of adjacent second machine direction yarns.

[0058] Preferably, the first group(s) and the second groups are arranged alternately in the machine direction and / or the machine transverse direction. Furthermore, adjacent first machine direction yarns in the first group(s) can be offset from each other in the machine direction, and / or adjacent second machine direction yarns in the second group(s) can be offset from each other in the machine direction.

[0059] Preferably, the first machine directional yarns can form first separation zones, each formed by a plain weave sequence with at least three successive machine cross-directional yarns, and / or the second machine directional yarns can form second separation zones, each formed by a plain weave sequence with at most 15 successive machine directional yarns.

[0060] According to a fourth aspect of the present invention, a paper machine covering fabric is provided for a fiber web forming and / or converting machine. The fabric comprises a first side and a second side opposite the first side, a machine direction and a machine cross direction, as well as several machine direction yarns which are interwoven with several machine cross direction yarns to form a pattern repeat on the first side.For each pattern repeat, a machine-directional yarn forms numerous MD floats in the machine direction, separated from each other by separation zones. Each MD float is formed by passing a machine-directional yarn over several successive machine-transverse yarns on the first side, and each separation zone is formed by at least one float of the machine-directional yarn over at least one machine-transverse yarn on the second side. The fabric according to the fourth aspect of the present invention is characterized in that the pattern repeat comprises several third machine-directional yarns. Each of the third machine-directional yarns forms at least one first MD float with a first float length and at least one subsequent second MD float with a second float length.The first length is smaller than the second length, wherein the first and second MD floats are separated by a third separation zone formed by a plain weave sequence of the third machine directional yarn with at least three successive machine cross directional yarns or a float of the third machine directional yarn over a machine cross directional yarn on the second side.

[0061] According to a preferred embodiment of the fourth aspect, the pattern repeat can comprise several first machine direction yarns, each forming several first MD floats successive in the machine direction.

[0062] All fabrics according to the various aspects of the present invention mentioned above can be single-ply fabrics. The first side of these fabrics can provide a paper contact surface, and the second side can provide a machine contact surface. All these fabrics can be used in a forming or drying section of a paper or nonwoven web manufacturing machine. If the fabric is used in a drying section, it can be a so-called through-air dryer fabric (TAD fabric). Furthermore, at least some, preferably all, of the machine directional yarns forming the MD floats can have a flattened cross-section. Description of the drawings:

[0063] The invention is described in more detail below with reference to non-restrictive drawings showing two preferred embodiments of fabrics according to the present invention. Fig. Figure 1 shows a schematic view of a pattern repeat on the first side of a fabric according to a first embodiment of the present invention, Fig. Figure 2 shows a photographic top view of the first side of the fabric made of Fig. 1, Fig. Figure 3 shows a schematic view of a pattern repeat on the first side of a fabric according to a second embodiment of the present invention and Fig. Figure 4 shows a photographic top view of the first side of the fabric made of Fig. 3.

[0064] At the in Fig. 1 and Fig. The fabric 100 shown in Figure 2 is a single-layer fabric consisting of a system of machine-woven cross-directional yarns (hereinafter referred to as CD yarns) A to T, woven in a pattern repeat with a system of machine-woven directional yarns (hereinafter referred to as MD yarns) 1 to 20. The pattern repeat consists of 20 MD yarns x 20 CD yarns. The fabric 100 has a first side 101 and a second side opposite the first side, as well as a machine direction MD and a machine-woven cross direction CD.

[0065] Fig. Figure 1 shows a schematic top view of a pattern repeat on the first page 101 of fabric 100. Each dark square in Fig. 1 indicates where an MD yarn is passed over a CD yarn on the first page 101. Each light square in Fig. 1 indicates where an MD yarn is passed over a CD yarn on the second page, or in other words, where a CD yarn is passed over an MD yarn on the first page 101.

[0066] Fig. Figure 2 shows a photographic top view of the first page 101 of the fabric 100 made of Fig. 1, where more than one sample report is shown. The features described below are partly in Fig. 2 highlighted.

[0067] In the pattern repeat, each MD yarn (1 to 20) forms numerous MD floats (F1 or F2) that are consecutive in the MD direction of the machine. The successive MD floats (F1, F2) of MD yarns (1 to 20) are separated by separation zones (S1, S2), each formed by passing the respective MD yarn over at least one CD yarn (A to T) on the second side.

[0068] For example, MD yarn 11 forms two first MD floats F1 per pattern repeat, with a float length of seven CD yarns T + A to F + J to P. The first MD floats F1 of the respective MD yarn 11 are separated by separation zones S1. The separation zones S1 are formed by a plain weave sequence of a machine directional yarn 11 with three adjacent machine cross-directional yarns G, H, I and Q, R, S. The same applies to MD yarns 1 to 3, 8 to 13, and 18 to 20, which all form first floats F1 separated by first separation zones S1. MD yarns 1 to 3, 8 to 13, and 18 to 20 are referred to as first MD yarns. In the first MD yarns, the first MD floats F1 are arranged adjacent to each other in the machine direction MD, because no further MD floats are arranged between the first MD floats F1 of the same first MD yarn.

[0069] Furthermore, each of the MD yarns 5 to 7 and 14 to 17 forms two second MD floats F2 per pattern repeat, with a float length of five CD yarns (for example, MD yarn 7 forms one second MD float F2 over the adjacent CD yarns D to H and another second MD float F2 over the adjacent CD yarns N to R). The second MD floats F2 of the respective MD yarn are separated by second separation zones S2. The second separation zones S2 are formed by a plain weave sequence of the respective machine directional yarn with five adjacent machine cross-directional yarns (for example, MD yarn 7 forms one second separation zone with the CD yarns A to C + S to T and another second separation zone with the CD yarns I to M). The MD yarns 5 to 7 and 14 to 17 are referred to as second MD yarns.In the case of the second MD yarns, the second MD floats of the same second MD yarn are arranged adjacent to each other in the machine direction MD, because there are no further MD floats between the second MD floats F2.

[0070] The weaving pattern comprises several continuous compression zones, with a portion of each zone visible and indicated by a dashed line labeled CR. The MD floats forming a continuous compression zone are adjacent in the machine transverse direction CD and offset from each other in the machine direction MD. The continuous compression zones CR are formed by the first and second MD floats F1 and F2. The first and second separation zones S1 and S2 together form the trough V that separates the adjacent compression zones CR. The continuous compression zones CR extend at least the length of the pattern repeat without being interrupted by a trough V. The continuous compression zones CR extend diagonally to both the machine and machine transverse directions.The outer contour of the continuous compression zones CR is wavy.

[0071] As in Fig. As shown in Figure 1, the first MD yarns 8 to 13 form a first group of first MD floats F1, each with a first float length of seven CD yarns. A second group of second MD floats F2, formed by MD yarns 4 to 7, is arranged adjacent to the first group of first MD floats. All second MD floats have a second float length of five CD yarns, which is less than the first float length. As can be seen, the continuous compression area CR has at least one first group of MD floats 8 to 13 and at least one second group of MD floats 4 to 7. The at least one first group is formed by a first number of first MD floats F1, arranged adjacent to CD in the machine transverse direction. In this case, the first number is six (6).The at least one second group of second MD floats F2 is formed by a second number of second MD floats F2 arranged adjacent to each other in the machine transverse direction CD. In this case, the second number is four (4). The first and second groups are arranged alternately. The average offset of the first MD floats F1 in the first group is 1.4 (=[1+1+3+1+1] / 5), and the average offset of the second MD floats F2 in the second group is 3 (=[3+3+3] / 3). Therefore, the average offset in the first group is less than the average offset in the second group.

[0072] In addition, the first MD floats F1, which form the first group, have a first average float length, which in this case is seven (7) CD yarns, and the second MD floats F2, which form the second group, have a second average float length, which in this case is five (5) CD yarns. As can be clearly seen, the individual length of the MD floats forming the first group does not deviate from the first average float length, and the individual length of the MD floats forming the second group does not deviate from the second average float length.

[0073] Furthermore, it is evident that each of the MD floats F1, F2 has a float center point “X”. If the centers “X” of the first two adjacent MD floats are connected with a straight line (for example, the center point of the second MD float F2 formed by the third MD yarn 9 and the center point “X” of the second MD float F2 formed by the third MD yarn 10), a first center line (shown as a dotted line) is created, which runs at a first angle to the machine direction MD.If the centers “X” of two adjacent MD floats are connected with a straight line (for example, the center of the second MD float F2 formed by the third MD yarn 10 and the center “X” of the first MD float F1 formed by the first MD yarn 11), a second center line (shown as a dotted line) is created, which runs at a second angle to the machine direction MD that differs from the first angle.

[0074] Connecting all the center lines of the MD floats forming the respective continuous compression zone CR creates a center-connection line CLC, which runs essentially at an angle to the machine and machine transverse directions MD and CD, respectively. The center-connection line CLC is not straight and has at least two bends. In addition, the outer contour of the continuous compression zones is wavy.

[0075] During the Fig. 3 and Fig. The fabric 100 shown in Figure 4 is a single-layer fabric consisting of a system of CD yarns A to R woven in a pattern repeat with a system of MD yarns 1 to 20. The pattern repeat consists of 20 MD yarns x 18 CD yarns. The fabric 100 has a first side 101 and a second side opposite the first side, as well as a machine direction MD and a machine cross direction CD.

[0076] Fig. Figure 3 shows a schematic top view of a pattern repeat on the first page 101 of fabric 100. Each dark square in Fig. 3 indicates where an MD yarn is passed over a CD yarn on the first page 101. Each light square in Fig. 3 indicates where an MD yarn is passed over a CD yarn on the second page 101, or in other words, where a CD yarn is passed over an MD yarn on the first page 101.

[0077] Fig. Figure 4 shows a photographic top view of the first page 101 of the fabric. Fig. 3, where more than one pattern repeat is shown.

[0078] The pattern repeat comprises several first MD yarns, each first MD yarn, for example 10 to 12, forming several consecutive first MD floats F1. The pattern repeat further comprises several third MD yarns, for example 8, 9, 13, 14, each first MD yarn forming at least one first MD float F1 and at least one subsequent second MD float F2.

[0079] The successive MD floats F1, F2 of each of the MD yarns 1 to 20 are separated by first separation zones S1, second separation zones S2, third separation zones S3, fourth separation zones S4, or fifth separation zones S5. The first and second separation zones S1, S2 are the same separation zones as in the Fig. 1 and Fig. 2 of the preceding embodiment shown. The third separation zones S3 are formed by two successive bends of an MD yarn on the second side, each over a machine transverse yarn, separated from each other by a float of the MD yarn over three adjacent CD yarns on the first side. The fourth separation zones S4 are formed by a bend of an MD yarn over a CD yarn on the second side. The fifth separation zones S5 are formed by a float of an MD yarn over two adjacent CD yarns on the second side.

[0080] The weave pattern comprises several continuous compression zones, with a portion of each continuous compression zone visible and indicated by a dashed line labeled CR. The MD floats forming a continuous compression zone CR are arranged adjacent to each other in the machine transverse direction CD and offset from each other in the machine direction MD. The continuous compression zones CR are essentially formed by the first and second MD floats F1 and F2. The first to fifth separation zones S1 to S5 together form troughs V that separate the adjacent continuous compression zones CR. The weave pattern also includes non-continuous compression zones dCR, each surrounded by recessed troughs V.Each non-continuous compression zone dCR is formed by a number of MD floats that are adjacent in the machine transverse direction CD and offset in the machine direction MD, overlapping in the machine direction MD. The number of MD floats forming a non-continuous compression zone dCR is less than the number of MD floats forming a continuous compression zone CR.

[0081] The continuous compression zones CR extend at least the length of the pattern repeat without being interrupted by a trough V. The continuous compression zones CR extend diagonally to the machine direction and machine transverse direction.

[0082] As in Fig.As shown in Figure 3, the first MD yarns 11 to 14 in the continuous compression zone CR form a first group of first MD floats F1, each with a first float length of five (5) CD yarns. Adjacent to the first group of first MD floats F1, the continuous compression zone CR includes a second group of second MD floats F2, formed by MD yarns 7 to 10. All second MD floats F2 have a second float length greater than the first float length, consisting of seven (7) CD yarns. As can be seen, the continuous compression zone CR has at least one first group of MD floats and at least one second group of MD floats. The at least one first group is formed by a first number of first MD floats F1 adjacent to CD in the machine transverse direction. In this case, the first number is four (4).The at least one second group of MD floats F2 is formed by a second number of second MD floats F2 that are adjacent in the machine transverse direction CD. In this case, the second number is three (3). The first and second groups are arranged consecutively. The average offset of the first MD floats F1 in the first group is 1 (=[1+1+1+1] / 4), and the average offset of the second MD floats F2 in the second group is 3 (=[3+3+3] / 3). Therefore, the average offset in the first group is less than the average offset in the second group.

[0083] In addition, the first MD floats F1, which form the first group, have a first average float length of five CD yarns in this case, and the second MD floats F2, which form the second group, have a second average float length of seven CD yarns in this case. As can be clearly seen, the individual length of the MD floats forming the first group does not deviate from the first average float length, and the individual length of the MD floats forming the second group does not deviate from the second average float length.

[0084] Furthermore, it is evident that each of the MD floats F1, F2 has a float center point “X”. If the centers “X” of the first two adjacent MD floats are connected with a straight line (for example, the center point of the second MD float F2 formed by the third MD yarn 9 and the center point “X” of the second MD float F2 formed by the third MD yarn 10), a first center line (shown as a dotted line) is created, which runs at a first angle to the machine direction MD.If the centers “X” of two adjacent MD floats are connected with a straight line (for example, the center of the second MD float F2 formed by the third MD yarn 10 and the center “X” of the first MD float F1 formed by the first MD yarn 11), a second center line (shown as a dotted line) is created, which runs at a second angle to the machine direction MD that differs from the first angle.

[0085] Connecting all the center lines of the MD floats forming the respective continuous compression zone CR creates a center-connection line CCL, which runs essentially at an angle to the machine direction and the machine transverse direction. The center-connection line CCL is not straight and has at least two bends. In addition, the outer contour of the continuous compression zones is wavy.

Claims

[1] Paper machine covering fabric for a fiber web forming and / or converting machine, the fabric comprising a first side and a second side opposite the first side, a machine direction and a machine transverse direction, and several machine direction yarns interwoven with several machine transverse yarns to form a repeating weave pattern on the first side in a pattern repeat, wherein in each pattern repeat a machine direction yarn forms numerous successive MD floats in the machine direction on the first side, wherein an MD float is formed by passing a machine direction yarn on the first side over several adjacent machine transverse yarns, wherein the weave pattern comprises several compression areas separated from each other by recesses set back from the compression areas,wherein a compression zone is formed by several MD floats arranged adjacent to each other in the machine transverse direction, wherein the MD floats forming a compression zone overlap at least partially in the machine direction, and wherein at least a majority of these MD floats are offset from each other in the machine direction, characterized by , that at least one compression area has at least one first group of MD floats and at least one second group of MD floats, wherein the at least one first group is formed by a first number of adjacent MD floats, and the at least one second group is formed by a second number of adjacent MD floats, and wherein the average offset of the MD floats in the at least one first group is smaller than the average offset of the MD floats in the at least one second group. [2] Paper machine covering fabric according to claim 1, characterized by that the second number is less than the first number. [3] Paper machine covering fabric according to claim 1 or 2, characterized by , that all MD floats forming a compression area are offset from each other in the machine direction. [4] Paper machine covering fabric according to any one of the preceding claims, characterized by that each compression area includes at least a first and a second group. [5] Paper machine covering fabric according to any one of the preceding claims, characterized by that the first and second groups are arranged alternately. [6] Paper machine covering fabric according to any one of the preceding claims, characterized by that the compression zones are arranged adjacent to each other in the machine direction and / or the machine transverse direction. [7] Paper machine covering fabric according to any one of the preceding claims, characterized by that each first group is formed by at least four adjacent MD floats, preferably at least six adjacent MD floats. [8] Paper machine covering fabric according to any one of the preceding claims, characterized by that every second group is formed by at most eight adjacent MD floats, preferably by at most six adjacent MD floats. [9] Paper machine covering fabric according to any one of the preceding claims, characterized by , that the first groups are formed by first MD floats and the second groups by second MD floats, wherein the first MD floats have a first length and the second MD floats have a second length, and the first length is different from the second length. [10] Paper machine covering fabric according to claim 9, characterized bythat the first length is greater than the second length, or that the first length is smaller than the second length. [11] Paper machine covering fabric according to any of the preceding claims, characterized by , that the average offset of the MD floats in the first group is between 0 and 2.5, preferably 0.5 and 2. [12] Paper machine covering fabric according to any one of the preceding claims, characterized by , that the average offset of the MD floats in the second group is between 1.2 and 4. [13] Paper machine covering fabric according to any of the preceding claims, characterized by , that the offset of the adjacent MD floats in the first groups is such that the adjacent MD floats overlap in the machine direction by at least half their float length. [14] Paper machine covering fabric according to any one of the preceding claims, characterized bythat at least 50%, preferably at least 75% of all adjacent MD floats forming a compression area have an overlap of at least three successive machine cross yarns. [15] Paper machine covering fabric according to any one of the preceding claims, characterized by , that the contact area formed by the first groups differs from the contact area formed by the second groups by no more than 20% in relation to the total contact area of ​​the tissue on the first side. [16] Paper machine covering fabric according to any of the preceding claims, characterized by , that the pattern repeat includes at least one machine directional yarn forming several successive first MD floats, and at least one further machine directional yarn forming several successive second MD floats. [17] Paper machine covering fabric according to claim 16, characterized by, that the pattern repeat comprises several first machine direction yarns, with each first machine direction yarn forming several adjacent first MD floats. [18] Paper machine covering fabric according to claim 16 or 17, characterized by , that the pattern repeat comprises several second machine direction yarns, with each second machine direction yarn forming several adjacent second MD floats. [19] Paper machine covering fabric according to claim 16, 17 or 18, characterized by that the pattern repeat comprises several third machine direction yarns, each third machine direction yarn forming at least one first and at least one second successive MD float. [20] Paper machine covering fabric according to any one of the preceding claims, characterized by, that successive MD floats of each machine directional yarn are separated from each other by a separation zone, wherein the separation zone is formed by a crank and / or a float of the machine directional yarn over at least one machine transverse directional yarn on the second side. [21] Paper machine covering fabric according to any of the preceding claims, characterized by, that the pattern repeat comprises several separation zones, at least some of which are formed by i) a plain weave sequence of a machine directional yarn with at least three adjacent machine cross-directional yarns, or ii) a float of a machine directional yarn on the second side over at least two adjacent machine cross-directional yarns, or iii) a float of a machine directional yarn on the second side over a machine cross-directional yarn, or iv) two successive floats of a machine directional yarn on the second side, each over a machine cross-directional yarn, separated from each other by a float of the machine directional yarn over at most four adjacent machine cross-directional yarns on the first side. [22] Paper machine covering fabric according to any one of the preceding claims 20 to 21, characterized by, that the separation zones of all machine directional yarns contribute overall to the formation of the recessed troughs. [23] Paper machine covering fabric according to any one of the preceding claims 20 to 22, characterized by that the separation zones of adjacent machine direction yarns either overlap or are adjacent in the machine direction. [24] Paper machine covering fabric according to any one of the preceding claims, characterized by that the web pattern includes at least one continuous compression area and at least one non-continuous compression area. [25] Paper machine covering fabric according to claim 24, characterized by that each continuous compression zone is formed by at least 10 adjacent MD floats. [26] Paper machine covering fabric according to claim 24 or 25, characterized bythat the at least one non-continuous compression area is formed by no more than six MD floats, preferably no more than four MD floats. [27] Paper machine covering fabric according to any one of the preceding claims, characterized by , that a center-connecting line connecting the centers of all adjacent MD floats runs substantially at an angle to the machine and machine transverse directions. [28] Paper machine covering fabric according to claim 27, characterized by that the center-connecting line essentially runs in the direction of the machine. [29] Paper machine covering fabric according to claim 27 or 28, characterized by that the center-connecting line is not straight, preferably has at least two bend points. [30] Paper machine covering fabric according to claim 27, 28 or 29, characterized bythat the center-connecting lines of all continuous compression areas run parallel to each other. [31] Paper machine covering fabric according to any of the preceding claims, characterized by that the outer contour of the continuous compression areas is wavy. [32] Paper machine covering fabric according to any one of the preceding claims, characterized by , that each of the MD floats has a float center point, wherein a first center line connecting the centers of the first two adjacent MD floats runs at a first angle to the machine direction, and a second center line connecting the centers of the second two adjacent MD floats runs at a second angle different from the first angle to the machine direction. [33] Paper machine covering fabric according to any one of the preceding claims, characterized bythat the tissue is a single-layered tissue. [34] Paper machine covering fabric according to any one of the preceding claims, characterized by that the first side provides a paper contact surface and the second side provides a machine contact surface. [35] Paper machine covering fabric according to any one of the preceding claims, characterized by that at least some, preferably all, of the machine directional yarns forming the floats have a flattened cross-section. [36] Paper machine covering fabric for a fiber web forming and / or converting machine, the fabric comprising a first side and a second side opposite the first side, a machine direction and a machine transverse direction, and several machine direction yarns interwoven with several machine transverse direction yarns to form a pattern repeat on the first side, wherein in each pattern repeat a machine direction yarn forms numerous MD floats successive in the machine direction and separated from each other by separation zones, wherein an MD float is formed by passing a machine direction yarn on the first side over several adjacent machine transverse direction yarns, wherein each separation zone is formed by a crank and / or a float of the machine direction yarn over at least one machine transverse direction yarn on the second side, characterized by, that the pattern repeat comprises several first machine direction yarns and several second machine direction yarns, wherein the first machine direction yarns form first MD floats separated by first separation zones, and the second machine direction yarns form second MD floats separated by second separation zones, wherein the first MD floats in the machine direction have a first greater float length than the float length of the second MD floats, wherein the first separation zones in the machine direction are shorter than the second separation zones, wherein at least some, preferably all, of the separation zones are formed by a plain weave sequence of the machine direction yarn with at least three successive machine cross direction yarns. [37] Paper machine covering fabric according to claim 36, characterized bythat the first machine direction yarns per pattern repeat form several groups of adjacent first machine direction yarns. [38] Paper machine covering fabric according to claim 36 or 37, characterized by that the second machine direction yarns form several groups of adjacent second machine direction yarns per pattern repeat. [39] Paper machine covering fabric according to claim 36, 37 or 38, characterized by that the first groups and the second groups are arranged alternately in the machine direction and / or the machine transverse direction. [40] Paper machine covering fabric according to any one of the preceding claims 36 to 39, characterized by , that adjacent first machine direction yarns in the first groups are offset from each other in the machine direction, and / or that adjacent second machine direction yarns in the second groups are offset from each other in the machine direction. [41] Paper machine covering fabric according to any one of the preceding claims 36 to 40, characterized by , that the first machine directional yarns form first separation zones, each formed by a plain weave sequence with at least three successive machine cross-directional yarns. [42] Paper machine covering fabric according to any one of the preceding claims 36 to 41, characterized by , that the second machine directional yarns form second separation zones, each formed by a plain weave sequence with a maximum of 15 successive machine transverse directional yarns. [43] Paper machine covering fabric for a fiber web forming and / or converting machine, the fabric comprising a first side and a second side opposite the first side, a machine direction and a machine transverse direction, and several machine direction yarns interwoven with several machine transverse yarns to form a pattern repeat on the first side, wherein in each pattern repeat a machine direction yarn forms numerous MD floats successive in the machine direction and separated from each other by separation zones, wherein an MD float is formed by passing a machine direction yarn on the first side over several adjacent machine transverse yarns, wherein each separation zone is formed by at least one float of the machine direction yarn over at least one machine transverse yarn on the second side, characterized bythat the pattern repeat comprises several third machine direction yarns, each forming at least one first MD float with a first float length and at least one subsequent second MD float with a second float length, wherein the first length is smaller than the second length, wherein the first and second MD floats are separated by a third separation zone formed by a plain weave sequence of the third machine direction yarn with at least three successive machine direction yarns or a float of the third machine direction yarn over a machine cross direction yarn on the second side. [44] Paper machine covering fabric according to claim 43, characterized by that the pattern repeat includes several first machine direction yarns, each forming several first MD floats in succession in the machine direction.

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