MXPA99001508A - Papermaking belt having bilaterally alternating tie yarns - Google Patents

Abstract

A papermaking belt comprising a top (web facing) layer of interwoven top layer yarns, a bottom (machine facing) layer of interwoven bottom layer yarns, and a plurality of tie yarns. The top layer yarns comprise a plurality of top layer carrier yarns interwoven in a weave with a plurality of top layer cross-carrier yarns, the top layer carrier yarns being perpendicular to the top layer cross-carrier yarns. The bottom layer yarns comprise a plurality of bottom layer carrier yarns interwoven in a weave with a plurality of bottom layer cross-carrier yarns, the bottom layer carrier yarns being perpendicular to the bottom layer cross-carrier yarns. The top layer and the bottom layer are tied together in a parallel and interfacing relationship by a plurality of tie yarns having a general direction of the top layer carrier yarns and passing over the top layer cross-carrier yarns and under the bottom layer cross-carrier yarns in a repeating pattern. As each of the tie yarns passes over at least one of the top layer cross-carrier yarns and under at least one of the bottom layer cross-carrier yarns, each of the tie yarns bilaterally alternates about one top layer carrier yarn in the direction of the top layer cross-carrier yarns whereby forming an undulating line passing at spaced intervals completely underneath that top layer carrier yarn about which each of the tie yarns alternates.

Description

PAPER FORMING BAND WHICH HAS BILATERALLY ALTERNATING BANDS FIELD OF THE INVENTION The present invention relates to paper forming webs useful in machines for making tough, soft absorbent paper products. More particularly, this invention relates to bands consisting of two layers.

BACKGROUND OF THE INVENTION Paper products are used for a variety of purposes. Paper towels, facial tissues, toilet paper and the like, are of constant use in modern industrialized societies. The high demand for these paper products has created a demand for improved versions of the products. In general, the paper manufacturing process includes several steps. An aqueous dispersion of the papermaking fibers takes the form of an embryonic web on a foraminate member, such as the Fourdrinier mesh, or in a double mesh machine, where initial dewatering and rearrangement of the fibers occurs. In an air-drying process, after initial dewatering, the embryo plot is transported to a P755 air drying band consisting of an air permeable deflection member. The deflection member may consist of a recorded resinous structure having a large number of deflection conduits through which air can flow at differential pressure. The resinous structure is attached to a woven reinforcement structure and extends outwards. Fibers for the manufacture of paper in the embryonic web are deflected in the deflection ducts and the water is removed through them to form an intermediate web. Then the intermediate web is dried in the final drying step, in a manner similar to that of conventional papermaking described above. In the final drying step, the portion of the plot registered with the resinous structure can be subjected to printing - to form a multiple regions structure. Air-dried paper webs are made in the manner generally described in co-assigned U.S. Patent 4,514,345 issued to Johnson et al. On April 30, 1985; U.S. Patent 4,528,239 issued to Trokhan on July 9, 1985; U.S. Patent 4,529,480 issued to Trokhan on July 16, 1985; U.S. Patent 4,637,859 issued to Trokhan on June 20, 1987; United States Patent 5,334,289 granted to P755 Trokhan et al. On August 2, 1994. The above patents are incorporated herein by reference, for the purpose of showing the preferred constructions of the resinous etched structures and the reinforcing structures of the air drying type. Such bands have been used to produce commercially successful products such as Bounty paper towels and Charmin Ultra toilet paper, both produced and marketed by the present assignee. The woven reinforcing structure of the air drying bands stabilizes and reinforces the resinous structure and reduces the permeability of the paper forming web. Therefore, the reinforcement structure must have an open, adequate, projected area to allow the vacuum dewatering equipment used in the papermaking process to adequately perform its function of removing water from the plot intermediate and allow the water to be removed from the web by passing through the paper forming web. Therefore, the reinforcement structure must be highly permeable to fluids such as water and air. At the same time, the reinforcement structure also plays an important supporting role to the cellulosic fibers, by not allowing them to be completely separated from each other or to be dispersed through the paper forming band as a consequence of P755 the application of a vacuum pressure. These phenomena cause pinhole-sized holes or pitting in the paper web. A large number of bites reduces the quality of the paper and can negatively affect the perception of the consumer with respect to the paper product. Thus, the degree of support that provides the fibers with the reinforcement structure is of fundamental importance. Generally, there is an exchange between air permeability and fiber support of a paper forming web. This exchange is especially sensitive in the air drying bands which must have a suitable open area to eliminate water from the weft through the forming band. The improvement of a band in terms of fiber support by reducing its projected open area reduces the air permeability, or vice versa, the improvement of the band in terms of air permeability by increasing its projected open area reduces fiber support. To alleviate the negative consequences of this exchange between air permeability and fiber support of a paper-forming web, the first air-drying strips consisted of a fine-mesh reinforcing element. Although this fine mesh provided acceptable fiber support, it was generally impractical because it did not provide the strength and strength required for the high temperatures encountered in the papermaking process. A new generation of air drying paper forming bands was directed towards these interests. In these bands, a double layer reinforcement structure significantly improved the bond strength and durability of the bands. In some double layer reinforcement structures, a single yarn system in the cross machine direction is tied to two layers of yarns in the machine direction, which results in machine direction yarns crammed or stacked vertically . The use of a triple layer band further improves the fiber support of the reinforcing structure. A triple-layer band consists of two completely independent woven layers, an upper layer and a lower layer, each having its own yarns in the machine direction, woven with the yarns in the direction transverse to the machine. The two separate woven elements are tied together with lacing threads. Preferably, the upper layer or the one facing the weft of the triple layer band, has a finer mesh than the lower layer or the one facing the machine. The finer mesh provides better support for the fiber and minimizes the amount of pitting. The lower layer uses thicker threads to increase stiffness and improve bond strength. In a triple layer band, the mooring threads can be added specifically to make the function of joining the two independent layers, without being present in each of the layers as an inherent part of their structure. Alternatively, the tie wires can be the integral strands forming the upper and / or lower layers of the reinforcing structure. In both cases, the tie wires can be oriented either in the machine direction or in the cross machine direction. Mooring threads in the machine direction are preferred due to the increase they provide in the joining force. European Patent WO 91/14813 granted to Wright on October 3, 1991 and assigned to Asten Group Inc., discloses a two-ply fabric having a top layer that leads to paper containing twice as many threads in a transverse direction. the machine that the lower layer, facing the machine. A thread system in the machine direction is woven with a pattern selected as the one that produces a zig zag effect on the underside of the fabric to provide better drainage.

U.S. Patent 5,454,405 issued to Hawes on October 3, 1995 and assigned to Albany International Corp. discloses a triple layer paper forming fabric having a system of upper weft yarns and a system of lower woven weft yarns in pairs with first and second warp threads. The second warp yarns have relatively little ripple which increases the stretch resistance in the fabric. Although the use of double layer and triple layer reinforcement structures helps to balance the exchange between fiber support and air permeability of the band, the use of double and triple layer structures can not, for if they themselves, uncouple these intimately related characteristics in an inherent way. Accordingly, it is an object of the present invention to provide a paper-forming web that significantly reduces the negative consequences of the exchange between air permeability and support to the fibers of the web. It is a purpose of the present invention to increase the air permeability available in the web with a constant fiber support or to increase the fiber support available in the web with a constant air permeability.

SUMMARY OF THE INVENTION A paper forming web of the present invention consists of three primary elements: a top layer of interwoven threads of the top layer, a bottom layer of interwoven threads of the bottom layer and a plurality of anchor threads. In its preferred embodiment, the paper forming web is an endless web woven band having one side facing the weft and one side facing the opposite machine to the first. The paper forming web of the present invention may also have a resinous structure bonded thereto and extending outwardly from the face side of the upper layer web to form a contact surface with the web in the web forming band. paper. The upper layer yarns include a plurality of upper layer conveyor yarns interwoven into a fabric with a plurality of transverse conveyor yarns. The conveyor yarns of the upper layer are practically perpendicular to the transverse conveyor yarns of the upper layer. Preferably, the plurality of conveyor yarns of the upper layer are oriented in the machine direction. Alternatively, the plurality of conveyor yarns of the upper layer can be oriented in the direction transverse to the machine. The yarns of the lower layer comprise a plurality of conveyor yarns of the lower layer interwoven in a fabric with a plurality of transverse conveyor yarns of the lower layer. The conveyor yarns of the lower layer are practically perpendicular to the transverse conveyor yarns of the lower layer. Preferably, the plurality of conveyor yarns of the lower layer are oriented in the machine direction. The upper and lower layer are tied in a substantially parallel relationship and found by a plurality of tie wires having the same general direction as the plurality of conveyor wires of the upper layer. Mooring threads can include added mooring threads. The added lanyards are not inherent to the fabric of the upper or lower layers and are used only for the purpose of joining the upper layer and the lower layer. Alternatively, the lashing strands may include integral tie-down strands. The integral lanyards are in the fabric of the upper layer and / or the lower layer. The integral tie-down strands may be upper integral tie down strands, lower integral tie strands or upper / lower tie down strands. Mooring threads cross by P755 above the transverse conveyor threads of the upper layer and below the conveyor yarns of the lower layer in a pattern of repetition such that each of the plurality of tie wires cross at intervals spaced above at least one of the transverse conveyor yarns of the upper layer and by under at least one of the transverse conveyor threads of the lower layer. As the lacing threads cross above the transverse conveyor threads of the upper layer and below the transverse conveyor threads of the lower layer, each of the tie wires alternate bilaterally around at least one of the conveyor yarns of the upper layer and / or at least one of the conveyor yarns of the lower layer. Each of the mooring threads alternates in the direction of the transverse conveyor threads of the upper layer. As a consequence of this bilateral alternation, each of the mooring lines forms an undulating line that passes completely underneath at least one of the conveyor threads of the upper layer, around which this mooring thread alternates, at intervals spaced between two adjacent maxima of bilateral alternation of each of the mooring threads.

P755 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a fragmentary view of the upper plane of a strip according to the claimed invention, having added lanyards and a structure, and shown partly in section for clarity. For clarity the lower layer is not shown. Figure IA is a view of the upper plane of a band, similar to Figure 1, but having a more homogeneous distribution of maximum bilateral alternation than the band illustrated in Figure 1. Figure 2 is a vertical sectional view cross section taken along the line 2-2 of FIG. 1, showing an element of the structure and the added lanyards forming undulating lines that pass completely below the conveyor threads of the upper layer and of the conveyor threads of the lower layer. Figure 3 is a vertical cross-sectional view taken along line 3-3 of FIG.l. Figures 2-3 show the resinous structure in transparency. Figure 4 is a vertical cross-sectional view of the claimed strip according to the invention, showing the added lanyards forming undulating lines that pass completely below only the strands.

P755 upper layer conveyor yarns. Figure 5 is a vertical cross-sectional view of the claimed band according to the invention, which has fewer conveyor yarns of the lower layer than of the upper layer. Figure 6 is a vertical cross-sectional view of the claimed strip according to the invention, showing the lower integral tie wires. Figure 7 is a vertical cross-sectional view perpendicular to the view shown in FIG.

Figure 2, showing the added lanyards forming undulating lines that pass completely below the conveyor yarns of the upper layer and the conveyor yarns of the lower layer. Figure 8 is a vertical cross-sectional view similar to the view shown in the Figure 3, showing lower integral tie-down threads passing completely below a conveyor yarn of the upper layer and forming a "one-up / seven-down" repetition pattern of the tie layers interwoven with the top layer. Figure 9 is a vertical cross-sectional view similar to the view shown in Figure 8 and showing another embodiment of the lower integral tie wire.

P755 Figure 10 is a vertical cross-sectional view similar to the view shown in Figure 8, showing another embodiment of the lower integral tie-down thread forming a "one-up / five-down" repetition pattern of the tie layers interwoven with the top layer. Figure 11 is a vertical cross-sectional view similar to the view shown in Figure 10, showing yet another embodiment of the lower integral tie-down thread forming a "one-up / three-down" repetition pattern of the tie layers interwoven with the top layer. Figure 12A is a schematic cross-sectional view of the web having upper / lower integral tie wires. Figure 12B is a view similar to that of Figure 12A showing another embodiment of the band having upper / lower integral tie down wires. Figure 13 is a view of a plane of the paper forming web of the prior art, showing non-alternating tie wires.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 1-11, the paper forming web 10 of the present invention is of Preferably an endless web of flat fabric that transports a web of cellulosic fibers from a forming mesh to a drying apparatus, typically a heated cylinder, such as a Yankee drying cylinder (not shown). Although the preferred embodiment of the paper forming web 10 is in the form of an endless band, this can be incorporated in other diverse forms which include, for example, regulatory plates that are used in the manufacture of rotating sheets or drums that are used with other types of continuous processes or in batches. The paper forming web 10 of the present invention consists of three main elements: an upper layer 12 of yarns of the interwoven upper layer 100, a lower layer 20 of yarns of the interwoven lower layer 200, a plurality of binding yarns 300. The upper layer 12 is a face-to-face layer and the lower layer 20 is a face-to-face layer 10 layer. As will be discussed later in more detail, the terms and the reference numbers "layer threads" upper 100"," lower layer yarns 200"," tie ropes 300"are generic terms and reference numbers that include and designate different types of upper layer yarns, lower layer yarns, tie ropes, respectively. Now with reference to Figures 1-3, the layer P755 upper 12 has a side 14 facing the weft and the lower layer 20 has a side 24 facing the machine. The band 10 may consist of a structure 40 attached to the band 10 and extending outwardly from the side facing the weft 14 of the upper layer 12 to form a contact surface with the weft 44. Preferably, the structure 40 is molded from a photosensitive resin onto the top layer 12. When made from a photosensitive resin, the structure 40 penetrates the structure of the web 10 and is cured within any desired pattern by irradiating the liquid resin with Actinic radiation through a binary mask that has opaque sections and transparent sections. A variety of suitable resins can be used as structure 40. U.S. Patent 4,529,480; U.S. Patent 4,514,345; U.S. Patent 4,528,349; U.S. Patent 5,334,289 mentioned above, which describe structure 40 in more detail, are incorporated herein by reference. The yarns of the upper layer 100 of the paper forming web 10 consist of a plurality of conveyer yarns of the upper layer 110 interwoven in a fabric with a plurality of transverse conveyor yarns of the upper layer 120. The yarns P7S5 upper layer conveyors 110 are practically perpendicular to the transverse conveyor yarns of upper layer 120. Figure 1 shows a preferred square fabric one-up / one-bottom of the yarns of upper layer 100, but it must be recognized that other tissue patterns can be used. Examples of suitable weaving patterns include, but are not limited to, twill, twill twill, semi-twill, and multi-cut satins. In the same way as the threads of the upper layer 100, the threads of the lower layer 200 consist of a plurality of conveyor yarns of the lower layer 210 interwoven in a fabric with a plurality of transverse conveyor yarns of the lower layer 220, the conveyor yarns of the lower layer 210 being substantially perpendicular to the transverse conveyor yarns of the lower layer 220. Preferably, but not necessarily, the lower layer 20 has a square weave to maximize the binding force. As used herein, the yarn of the upper layer 100 is generic and includes the conveyor yarns of the upper layer 110 and the transverse conveyor yarns of the upper layer 120. In an analogous manner, the yarn of the lower layer 200 is generic and inclusive for the conveyor yarns of the lower layer 210 and the yarns P755 transverse conveyors of the lower layer 220. It is preferred that the conveyor yarns of the upper layer 110 and the conveyor yarns of the lower layer 210 have an address to the machine. Alternatively, the conveyor yarns of the upper layer 110 and the conveyor yarns of the lower layer 210 may have a direction transverse to the machine. As will be recognized by one skilled in the art, the term "machine direction" refers to the direction, which is parallel to the main flow of the paper web along the papermaking equipment. The "cross machine direction" is perpendicular to the machine direction and is located within the plane of the web 10. The machine direction of the conveyor wires 110, 210 is preferred to maximize the strength of the joint of the band 10. However, arrangements can also be used that have the conveyor yarns 110, 210 arranged in the transverse direction to the machine. As shown in Figures 2-11, the upper layer 12 and the lower layer 20 are bonded together in a substantially parallel relationship and found by means of the plurality of the tie wires 300. Preferably, the top layer 12 and Lower layer 20 are tied together in a splice relationship. If desired, as shown in P755 Figure 2, each conveyor wire of the upper layer 110 is stacked or stacked in a vertical alignment with a conveyor wire of the lower layer 210; and as shown in Figure 3, each transverse conveyor yarn of the upper layer 120 is stacked or stacked in a vertical alignment with a transverse conveyor yarn of the lower layer 220. Although the modality having a vertical alignment is preferred, it does not it is necessary. For example, only the conveyor yarns 110, 210 can be stacked or stacked in a vertical alignment, while the transverse conveyor yarns 120, 220 are not, or vice versa. Also, the upper layer 12 and the lower layer 20 may be slightly offset from each other from the vertical alignment in the direction of the conveyor yarns 110, 210 or in the direction of the transverse conveyor yarns 120, 220. The upper layer 12 may have the yarns of the upper layer 100 spaced more closely than the yarns of the lower layer 200 are - to provide sufficient support for the fibers. Figure 9 depicts the manner in which one of each two transverse conveyor yarns of the upper layer 120 is stacked or stacked in a vertical alignment with a transverse conveyor yarn of the lower layer 220. As best seen in Figures 1 and 1A , the P75S tie wires 300 have the same general direction as the conveyor wires of top layer 110. It will be noted that, for purposes of illustration, the tie wires 300 have been shaded in Figures 1-11 and 13. As shown in FIG. Figure 1, the tie wires 300 pass over some of the transverse conveyor yarns of the top layer 120 in a repeating pattern. The pattern of repetition is formed by the plurality of tie-wires 300 as each tie-string 300 passes at intervals spaced above at least one of the transverse conveyor yarns of the top layer 120 and below at least one of the transverse conveyor yarns of the lower layer 220. (The transverse conveyor yarns of the lower layer are not shown in Figure 1 for clarity). With respect to the upper layer 12, the spaced interval shown in Figures 1 and 1A includes eight transverse conveyor yarns of the upper layer 120. In other words, in view of the implication of an individual tie-down thread 300, the pattern of repetition shown in Figures 1 and 1A is formed with each individual anchor thread 300 by passing over a transverse conveyor wire of the upper layer 120, then passing below seven transverse conveyor wires of the upper layer 120, then going by P755 on top of a transverse conveyor yarn of the upper layer 120, then again passing under seven transverse conveyor yarns of the upper layer 120 and so on (ie, a "one-up / seven-down" pattern. best seen in Figure 3, when the tie wire 300 passes through under the seven transverse conveyor yarns of the top layer 120, the tie thread 300 also passes under at least one of the transverse conveyor wires of the lower layer 220, whereby the upper layer 12 is joined to the lower layer 20. One of ordinary skill in the art will recognize that the "one-up / seven-down" pattern of the fabric of the tie-down threads 300 with the layer upper 12 is a preferred but not necessary embodiment of the band 10 of the present invention For example, Figure 10 shows a "one-up / five-down" pattern and Figure 11 shows a "one-up / three-below "of the tissue d and the tie wires 300 with the top layer 12. The examples shown in Figures 1-12 are presented for purposes of illustration only and not for purposes of limitation. As will be noted above, the preferred embodiment of the band 10 is in the form of an endless band. Therefore, it should be recognized that, in the sense in which they are used in the present, the terms P755"above", "above", "below", "below" are relative terms, whose descriptive meanings are consistent with the descriptive meanings of the terms "upper layer 12" and "lower layer 20" of band 10 as it is shown in the cross-sectional views shown in Figures 2-11 and used in its normal and ordinary position in a papermaking machine. Returning to Figure 1, as each tie wire 300 passes or knits above at least one of the transverse conveyor yarns of the top layer 120, each tie thread 300 alternates bilaterally around at least one of the upper layer 110 conveyor yarns. As shown in Figure 1, each tie wire 300 alternates bilaterally around the corresponding conveyor yarn of the upper layer 110 in the direction of the transverse conveyor yarns of the upper layer 120. In the Preferred embodiment, at the point where the lanyard 300 passes over the transverse conveyor wire of the upper layer 120, the lanyard 300 reaches its maximum of bilateral alternation. As used herein, the term "bilateral alternating maximum" refers to the largest deviation of the lanyard 300 from the longitudinal axis of the corresponding conveyor wire 110, measured in the plane of the band. 10. A P755"corresponding" conveyor yarn (or simply, a corresponding yarn) is the conveyor yarn around which the binding yarn 300 alternates in the plane of the band 10. It should be carefully observed that the corresponding yarn can be an inherent element of the yarn. fabric of the upper layer 12, of the lower layer 20, or both - the upper layer 12 and the lower layer 20. As a consequence of the bilateral alternation, each tie-string 300 forms an undulating line that passes completely below the thread conveyor of the upper layer 110 at spaced intervals between two adjacent alternating maxima of this tie-in thread 300. It should be noted that when the tie wires 300 pass over the transverse conveyor yarns of the top layer 120, the yarns of mooring 300 preferably does not extend above the conveyor yarns of the upper layer 110 and therefore, does not interfere with the planar tissue character or preferred for the side facing the web 14 of the web 10. Figures 1 and IA show two different general patterns of distribution of the maximum bilateral alternating of the tie threads 300. Figure 1 represents a general pattern having zones Concentrates of maximum bilateral alternation (which run "diagonally" in relation to the direction of the machine in Figure 1).

P755 Figure IA shows a general pattern that has the maximum of bilateral alternation which is less concentrated than the pattern shown in Figure 1. The pattern shown in Figure IA is preferred, because it provides a more regular and homogeneous distribution of the clogged areas created in and around the maximum bilateral alternating points of the tie wires 300. The general pattern shown in Figure 1A is depicted for purposes of illustration and not for limitation purposes. It will be readily understood by one skilled in the art that other distribution patterns of maximum bilateral alternation of tie-wires 300 can be used, which provide a more regular distribution of maximum bilateral alternation of tie-wires 300 across the entire band 11. For example, a non-uniform general pattern (not shown) can be used, in which the maximum bilateral alternation is distributed non-repetitively or even disorderly. Preferably, each lanyard 300 is in direct contact with its corresponding conveyor wire 110 at the point where the lanyard 300 reaches its maximum of bilateral alternation. Therefore, the corresponding conveyor wires 110 do not allow the tie wires 300 to stretch in a completely straight line and to be parallel to the conveyor wires 110 between two P755 Adjacent bilateral alternating maxima even if the lashing threads 300 are pre-stretched in the machine direction. The specific fabric of the band 10 of the present invention results in tie-off yarns 300 forming undulating lines. Therefore, there is no need for a special pretreatment of the tie wires 300 (for example, chemical or thermosetting treatment) in order to cause the tie wires 300 to form undulating lines. While the tie wires 300 are preferably never parallel with respect to their corresponding conveyor yarns of the upper layer 110 between two adjacent bilateral alternating maxima, it will be carefully observed that the tie wires 300 have the same general direction as the conveyor wires of the upper layer 110, as indicated above and shown in Figure 1. In the sense in which it is used herein, the term "general direction" designates an address of the lanyard threads 300 which is presented as along a series of at least four consecutive highs of bilateral alternation. With respect to the lower layer 20, Figures 3, 7, 8, 9, 10 and 11 represent different embodiments of the band 10 of the present invention. First, it should be noted that the tie wires 300 may comprise P755 added lanyards 330. Alternatively, lanyard threads 300 may comprise integral lanyards 350. In the sense in which it is used herein, lanyard 300 is considered to be an "added lanyard 330"if it is not inherent to the selected fabric either for the upper layer 12 or for the lower layer 20. That is to say, the upper layer 12 and the lower layer 20 exist as independent structures of the interwoven yarns of the upper layer 100 and of the interwoven threads of the lower layer 200 respectively, without taking into account the existence of the added lanyards 330. The added threads 330 are used only for the purpose of attaching the upper layer 12 and the lower layer 20 and may still alter the ordinary fabric of these upper and lower layers 12, 20. Preferably, the added lanyards 330 are smaller in the cross-sectional area than the threads of the upper layer 100 and that the threads of the cap to lower 200. In the sense in which it is used herein, tie-down thread 300 is considered to be an "integral tie-down thread" 350 if it is an inherent element to the fabric of top layer 12, of the bottom layer 20 or both of the upper layer 12 and the lower layer 20. The integral anchor thread 350 is a "lower integral tie-down thread" if it is an inherent element of the layer fabric P755 lower 20 and only occasionally passes over the upper transverse conveyor wire 120. The integral anchor wire 300 is an "upper integral tie-down thread" if it is an inherent element to the fabric of the upper layer 12 and occasionally passes under the thread lower transverse conveyor 220. Figures 8, 9 show two embodiments of the band 10 of the present invention having the lower integral tie threads 352 that are preferred. In the two embodiments shown in Figures 8 and 9, the lower layer 20 consists of the lower integral tie threads 350 which are interwoven with the lower transverse conveyor wires 220. In the two embodiments shown in Figures 8 and 9, the lower integral tie threads 350 also function as (and are in fact) the conveyor yarns of the lower layer 210. It will be apparent to one skilled in the art that in the band 10 having the upper integral tie wires 350 , the upper layer 12 consists of the upper integral anchor threads 350 interwoven with the transverse conveyor threads of the upper layer 120. In this case, the upper integral anchor threads 350 also function as conveyor yarns of the upper layer 120. The latter This modality is not illustrated, but it can be easily imagined by turning Figures 8 and 9 to P755 reverse. In this case, as each upper integral tie-down thread 350 passes below or above at least one of the transverse conveyor wires of the lower layer 220, each upper integral tie-down thread 350 alternates bilaterally around at least one of the conveyor yarns of the lower layer 210. As a consequence of this bilateral alternation, each upper integral tie-down wire 350 forms an undulating line that passes completely above or below the conveyor wire of the lower layer 110 at intervals spaced between two maximums Adjacent Bilateral Alternating Upper Anchor Thread 350. One skilled in the art will recognize that a variety of possible patterns of the anchor threads 300 interwoven with the upper layer 12 and with the lower layer 20 of the band 10 can be used. Some of these patterns are shown in Figures 3, 7, 8, 9, 10 and 11. Figures 3, 7 represent the band 10 having the yarn. mooring lines 330, while Figures 8-11 represent the band 10 having the integral mooring threads 350. Figure 3 shows the typical embodiment of the band 10 comprising the added lanyards 330. In the band 10 shown in Figure 3, the added lanyard 330 is interwoven with the top layer 12 according to the "one-up / seven-down" pattern described above. The thread of P755 added mooring 330 interweaves with the lower layer 20 according to the similar pattern "seven-up / one-down". The transverse conveyor yarn of the lower layer 220 below which the added lanyard 330 passes while running under seven transverse conveyor yarns of the upper layer 120, is arranged to two adjacent intermediate transverse conveyor yarns of the upper layer 120 by on top of which the added lanyards 330 pass. As shown in Figure 3, most of the added lanyard length 330 is disposed between the upper layer 12 and the lower layer 20. Other embodiments of the lanyard are feasible. band 10 of the present invention, given the various combinations of the upper / lower layers vs. added / integrated lanyards and permutations of the aforementioned teachings. The combinations described are not intended to limit the present invention only to those described and shown in the foregoing. For example. FIGS. 12A and 12B schematically illustrate two embodiments of the band 10 in which the tie wire 300 consists of an upper / lower integral tie-off thread 390. As the term suggests, the upper / lower tie-down thread 390 is an inherent element of the fabric of both the top layer 12 P755 as in the lower layer 20. In this case, the plurality of the conveyor yarns of the upper layer 110 and the plurality of the conveyor yarns of the lower layer 210 consist of a plurality of upper / lower integral tie threads 390. When the conveyor yarns 110, 210 are oriented in the machine direction, the upper / lower integral tie threads 390 are the upper / lower integral tie threads 390 in the machine direction, as shown in Figures 12A and 12B . By analogy, when the conveyor yarns 110, 210 are oriented in the transverse direction to the machine, the upper / lower integral tie threads 390 are the upper / lower integral tie threads 390 in the transverse direction to the machine (not shown). As shown in Figures 12A and 12B, the upper layer 12 and the lower layer 20 are tied together in an almost parallel and found relationship by means of the upper / lower integral tie threads 390 in the machine direction. These upper / lower integral tie threads 390 in the machine direction pass over some of the threads of the upper directional layer transverse to the machine 120 and below some of the threads of the lower cross direction layer the machine 220 in a repetition pattern and at intervals spaced such that each of the P755 upper / lower integral tie threads 390 in the machine direction pass over at least one of the threads of the upper direction layer transverse to the machine 120 and below at least one of the threads of the lower layer of cross machine direction 220, each of the upper / lower integral tie threads 390 in the machine direction alternates bilaterally in the transverse direction to the machine around at least one thread of the top layer in the direction of the machine 110 (corresponding) and around at least one thread of the lower layer of the machine direction 210 (corresponding). (The wires 110 and 120 are not shown in Figures 12A and 12B for clarity). As a result of this bilateral alternation, each of the upper / lower integral tie threads 390 in the machine direction forms an undulating line having a general direction in the machine direction and passing completely under the corresponding thread of the machine. the top layer of the machine direction 110 and completely above the corresponding thread of the lower layer of the machine direction 210 at spaced intervals between two adjacent alternating two-sided maxima of each of the upper / lower integral tie wires of the address of the machine 390.

P755 It is important, especially in the case of air drying, that the strip 10 of the present invention allows sufficient air to flow perpendicular to the plane of the strip 10. Preferably, the air permeability of the strip 10 (which has no resinous structure 40 on it) of the present invention is greater than 500 standard cubic feet per minute (cfm) per square foot of surface at a differential pressure of 100 Pascals. More preferably, band 10 (which has no resinous structure 40 thereon) has an air permeability greater than 800 cfm at 100 Pascals. Although it is not intended to be limited to theory, it is believed that the band 10 of the present invention having bilaterally alternating lacing yarns provides increased air permeability compared to the similar band which has no alternating lanyards . Figure 13 illustrates the prior art and shows the band 700 having non-alternating lanyards 800. As shown in Figure 13, the non-alternating lanyards 800 of the prior art considerably reduce the projected open areas. between reciprocally perpendicular interwoven strands 100, 200. In the present invention, the tie threads 300, by virtue of their bilateral alternation, minimize the reduction of the open area of the band 10 and by P755 thus minimize interference with the air flow through the band 10. Two bands of two layers are compared - first, the band 10 of the present invention, which has the alternating lanyards; and second, the 700 band of the prior art, which has tie-down threads that do not alternate. The two bands 10 and 700 have the following characteristics: the diameter of the conveyor yarns of the upper layer is 0.15 mm, the number of conveyor yarns of the upper layer is 45 threads per inch, the diameter of the transverse conveyor yarns of the upper layer is 0.15 mm, the number of transverse conveyor yarns of the upper layer is 48 threads per inch; the diameter of the conveyor yarns of the lower layer (lower integral tie wires) is 0.15 mm; the number of conveyor yarns of the lower layer (lower integral binding wires) is 45 threads per inch, the diameter of the transverse conveyor threads of the lower layer is 0.20 mm, the number of transverse conveyor threads P755 of the lower layer is 24 threads per inch. The two bands 10 and 700 have the inherent "one-up / one-down" fabric of the upper and lower layers and the "one-up / seven-down" fabric of the lower integral tie threads described above. The two bands 10 and 700 have the similar general pattern of locations in which the lanyard passes over the transverse conveyor threads of the upper layer, as shown in Figures 1 and 13, respectively (in the case of the band 10 of the present invention, these locations comprise the maximum of bilateral alternating mooring threads). Supposedly, because of the use of the identical fibers and the fabric patterns in the two bands, both bands have approximately the same support for the fibers. It is believed that the use of alternating lanyards in the first band 10 made according to the present invention increases the projected open area by at least 15%, compared to the projected open area of the second band 700 having mooring threads that are not alternating from the prior art. At the same time, the use of alternating lanyards 300 according to the present invention provides the necessary support for the fibers. In the sense in which it is used in the present "fiber support" and P755 especially, its physical characteristic "Index of Fiber Support" is defined in Robert L. Beran, "The Evaluation and Selection of Forming Fabrics" Tappi / April 1979, Vol. 62, No. 4, which is incorporated in the present for reference. As demonstrated above, there is an exchange between air permeability and fiber support of the paper forming web. Therefore, if the webs 10 and 700 are re-woven prophetically to be compared based on the same air permeability (or of the same projected open area), the use of the alternating yarns in the web 10 of this invention increases the Fiber Support rate to more than about 20%, compared to the 700 band of the prior art having almost the same projected open area but not the alternating lanyard yarns. The wires 100, 200, 300 may have a variety of cross-sectional shapes, among which circles, ovals, rectangles and other polygons are included in a non-exclusive manner. For example, the threads of the upper layer 100 and of the lower layer 200 can have cross-sectional areas in the form of circles of equal or unequal diameters, while those of the lanyard threads 300 can be flat. In any case, the cross-sectional area of the lower yarns 200 may be larger than the cross-sectional area of the yarns.

P755 upper threads 100. As a result, the cross-sectional area of the upper threads 100 can be larger than the cross-sectional area of the mooring threads 300. In general, the threads 100, 200, 300 of the forming band of the present invention can be produced from a wide range of synthetic resins. When used in an air drying band, the preferred material for the wires 100, 200, 300 of the band 10 is Poly (ethylene terephthalate). Although the present invention has been discussed and Figures 1-12 have been presented in terms of monofilament yarns, one skilled in the art will recognize that the yarns 100, 200, 300 may consist of multifilament yarns and folded monofilament yarns.

P755

Claims (20)

1. CLAIMS: 1. A paper forming web consisting of: a top layer of interwoven top layer yarns, these upper layer yarns comprising a plurality of upper layer transporting yarns woven into a fabric with a plurality of yarns transverse conveyors of the upper layer, these conveyor yarns of the upper layer being practically perpendicular to the transverse conveyor yarns of the upper layer; a lower layer of yarns of the interwoven lower layer, these yarns of the lower layer comprise a plurality of conveyor yarns of the lower layer interwoven in a fabric with a plurality of transverse conveyor yarns of the lower layer, these yarns being transporters of the layer bottoms substantially perpendicular to the transverse conveyor threads of the lower layer; the upper layer and the lower layer are tied together in a substantially parallel relationship and found by means of a plurality of tie wires having a general direction practically parallel to the conveyor yarns of the upper layer and to the conveyor yarns of the lower layer, these lashing threads pass over the transverse conveyor threads P755 of the upper layer and below the transverse conveyor yarns of the lower layer at intervals spaced in a pattern of repetition, such that each of the mooring yarns passes over at least one of the transverse the upper layer and below at least one of the transverse conveyor yarns of the lower layer, each of the tie wires alternate bilaterally around at least one of the conveyor yarns of the upper layer or at least one of the conveyor yarns of the lower layer in the direction of the transverse conveyor threads whereby each of the mooring threads forms an undulating line that passes completely below at least one of the conveyor threads of the upper layer or completely above. at least one of the lower conveyor threads, at intervals spaced between two adjacent maxima of bilateral alternating yarn Mooring 2. A band according to Claim 1, wherein the general direction of the plurality of tie wires is substantially parallel to the machine direction. 3. A band according to Claim 2, wherein the plurality of lanyards comprises added lanyards. P755 4. A band according to Claim 2, wherein the plurality of tie-down strands comprise integral tie-down strands. 5. A band according to Claim 4, wherein the plurality of tie wires comprises threads of the lower layer. 6. A band according to Claim 4, wherein the plurality of tie-wires comprises strands of the top layer. 7. A band according to Claim 5, wherein the plurality of tie wires additionally comprises threads of the top layer. A band according to Claim 2, wherein the cross-sectional area of the lacing yarns is smaller than the cross-sectional area of the yarns of the upper layer. A band according to Claim 8, wherein the cross-sectional area of the lacing yarns is smaller than the cross-sectional area of the threads of the lower layer. A band according to Claim 1, wherein the general direction of the plurality of tie wires is substantially parallel to the direction transverse to the machine. 11. A band according to Claim 10, in P755 where the plurality of lacing yarns comprises added lanyards. 12. A band according to Claim 10, wherein the plurality of lanyard threads comprise integral lanyards. 13. A band according to Claim 12, wherein the plurality of tie wires comprises threads of the lower layer. 14. A band according to Claim 12, wherein the plurality of tie wires comprises threads of the top layer. 15. A band according to Claim 13, wherein the plurality of tie-down yarns additionally comprises yarns of the upper layer. 16. A paper forming web comprising: a top layer of interwoven top layer yarns, these upper layer yarns comprising a plurality of upper layer yarns in the machine direction woven into a fabric with a plurality of yarns. yarns of the upper layer in the cross machine direction, these yarns of the upper layer being in the cross machine direction practically perpendicular to the yarns of the upper layer in the machine direction; a lower layer of threads of the lower layer P755 interwoven, these threads of the lower layer comprise a plurality of threads of the lower layer in the machine direction woven into a fabric with a plurality of threads of the lower layer in the cross-machine direction, these threads being of the layer lower in the transverse direction to the machine practically perpendicular to the threads of the lower layer in the machine direction; the top layer and the bottom layer are tied together in a substantially parallel relationship and found by means of a plurality of machine direction lanyards that pass over the threads of the upper cross direction layer to the machine and below the threads of the lower layer of cross-machine direction at intervals spaced in a repeat pattern, such that each of the lanyards in the machine direction passes over at least one of the yarns of the upper layer of direction transverse to the machine and below each of the threads of the lower layer of direction transverse to the machine, each of the lanyards in the machine direction alternates bilaterally around the at least one of the threads of the upper layer of the machine direction and at least one of the threads of the lower layer of the machine direction in P755 direction transverse to the machine, whereby each of the tie wires in the machine direction forms an undulating line that passes completely below at least one of the threads of the top layer in the machine direction to intervals spaced between two adjacent maxima of bilateral alternation of each of the tie wires in the machine direction. 17. A paper forming web comprising: a top layer of interwoven top layer yarns, the upper layer yarns comprising a plurality of upper layer yarns in the machine direction woven into a fabric with a plurality of yarns. yarns of the upper layer in cross-machine direction, the yarns of the upper layer in the machine direction are practically perpendicular to the yarns of the upper layer in the machine direction; a lower layer of yarns of the interwoven lower layer, the yarns of the lower layer comprise a plurality of yarns in the direction of the machine interwoven in a fabric with a plurality of yarns of the lower layer in the cross-machine direction, the threads of the lower layer in the direction transverse to the machine are practically perpendicular to the lanyards in the machine direction; the upper layer and the lower layer are tied P7S5 together in a substantially parallel relationship and found by means of the plurality of machine-direction lacing yarns passing over the threads of the top layer of machine-transverse direction at intervals spaced in a pattern of repetition of such that each of the lacing threads of the machine direction passes over at least one of the threads of the upper layer of direction transverse to the machine, each of the lanyards of the machine direction it alternates bilaterally around the corresponding thread of the upper layer of the machine direction in the direction transverse to the machine, whereby each mooring thread in the machine direction forms an undulating line that passes completely below the corresponding thread of the upper layer in the direction of the machine at intervals spaced between two maximums of bilateral alternation of each of the threads of mooring e of the address of the machine. 18. A paper forming web comprising: a top layer of interwoven upper layer yarns, the upper layer yarns comprising a plurality of upper layer yarns in the machine direction woven into a fabric with a plurality of yarns. threads of the top layer of cross-machine direction, the threads of the top layer of direction P755 across the machine are practically perpendicular to the threads of the upper layer in the machine direction; a lower layer of threads of the interwoven lower layer, the threads of the lower layer comprise a plurality of threads of the lower layer in the machine direction woven into a fabric with a plurality of threads of the lower layer in a direction transverse to the machine, the threads of the lower layer in the cross machine direction are practically perpendicular to the threads of the upper layer in the machine direction, the plurality of threads of the upper layer in the machine direction and the plurality of threads of the lower layer in the machine direction comprises a plurality of upper / lower integral tie threads in the machine direction; the top layer and the bottom layer are bonded together in a substantially parallel relationship and found by means of a plurality of upper / lower integral tie threads in the machine direction which pass over the threads of the upper layer and below of the threads of the lower layer at spaced intervals in a repeat pattern such that each of the plurality of integral mooring threads P755 top / bottom of the machine direction passes over at least one of the threads of the upper directional layer transverse to the machine or below at least one of the threads of the lower directional layer transverse to the machine , each of the upper / lower integral binding strands of the machine direction alternate bilaterally in the machine-transverse direction around a corresponding thread of the upper layer of the machine direction or around a corresponding thread of the machine. lower layer of machine direction, whereby each of the upper / lower integral tie wires of the machine direction form an undulating line that passes completely below the corresponding thread of the top layer of the machine direction or completely above the corresponding thread of the lower layer of the machine direction at intervals spaced between two adjacent maxima of Bilateral alternation of each of the lower integral tie / tie wires in the machine direction. 19. A paper-forming web according to claim 1 further comprises a structure that is bonded to said web and extends outwardly from one side facing the web of the top layer to form a contact surface with the web. plot. P755 20. A paper forming band according to Claim 17, further comprises a structure that attaches to said web and extends outwardly from one side facing the web of the top layer to form a contact surface with the web. P755 SUMMARY OF THE INVENTION A paper-forming web consisting of a top layer (facing the web) of interwoven top layer yarns, a bottom layer (facing the machine) of interwoven bottom layer yarns and a plurality of mooring threads. The yarns of the upper layer comprise a plurality of yarns transported from the upper layer interwoven in a fabric with a plurality of transverse conveyor yarns of the upper layer, the conveyor yarns of the upper layer are perpendicular to the transverse conveyor yarns of the upper layer . The yarns of the lower layer comprise a plurality of conveyor yarns of the lower layer interwoven in a fabric with a plurality of transverse conveyor yarns of the lower layer, the conveyor yarns of the lower layer being perpendicular to the transverse conveyor yarns of the lower layer . The upper layer and the lower layer are tied together in a parallel and found relationship by means of a plurality of tie wires having a general direction of the conveyor yarns of the upper layer and passing over the transverse conveyor wires of the upper layer and below the transverse conveyor threads of the lower layer in a pattern of P755 repetition. As each of the tie wires passes over at least one of the transverse conveyor yarns of the upper layer and below at least one of the transverse conveyor wires of the lower layer, each of the tie wires it alternates bilaterally around a conveyor yarn of the upper layer in the direction of the transverse conveyor yarns of the upper layer whereby an undulating line is formed which passes at intervals spaced completely below the conveyer yarn of the upper layer around which each of the mooring threads alternates. P755