Patent Application
20080105323
1. Field of the Invention
The present invention relates to fabrics employed in web forming equipment, such as papermaking and non-woven web forming equipment. More particularly, the preferred fabrics of this invention are employed as forming fabrics in web forming equipment; most preferably in papermaking machines.
2. Discussion of Background Information
Paper is conventionally manufactured by conveying a paper furnish, usually consisting of an initial slurry of cellulosic fibers, on a forming fabric or between two forming fabrics in a forming section, the nascent sheet then being passed through a pressing section and ultimately through a drying section of a papermaking machine. In the case of standard tissue paper machines, the paper web is transferred from the press fabric to a Yankee dryer cylinder and then creped.
Paper machine clothing is essentially employed to carry the paper web through these various stages of the papermaking machine. In the forming section the fibrous furnish is wet-laid onto a moving forming wire and water drainage from it is assisted by means of suction boxes and foils. The paper web is then transferred to a press fabric that conveys it through the pressing section, where it usually passes through a series of pressure nips formed by rotating cylindrical press rolls. Water is squeezed from the paper web into the press fabric as the web and fabric pass through the nip together. In the final stage, the paper web is transferred either to a Yankee dryer, in the case of tissue paper manufacture, or to a set of dryer cylinders upon which, aided by the clamping action of the dryer fabric, the majority of the remaining water is evaporated.
So called “triple layer” paper machine fabrics are well known in the art. These generally comprise paper side and machine side warp and weft yarn systems, which are bound together by additional binder yarns whose sole function is to join the two fabric layers. Such structures have caused sheet marking due to binder activity on the paper side fabric. More recently triple-layer fabrics have become available where interchanging pairs of yarns bind the two fabric layers together but also weave as part of the paper side weave to reduce sheet marking.
U.S. Pat. No. 5,437,315 to Ward (the '315 patent) discloses a triple-layer fabric with plain weave surface wherein, within the fabric weave repeat, each binder weft interchanges with a matching top weft once over a single paper side warp. The interchanging is such that when the binder weft appears in the paper side surface to bind with a paper side warp yarn the paper side weft yarn drops out of the paper side surface and floats between the fabric layers for a length of three paper side warp yarns. The potential dewatering restriction caused by a binder weft interlacing with a paper side warp alongside a paper side weft knuckle is, therefore, addressed by the '315 patent. However, because there are minimal binder and warp interlacings in the embodiment of the '315 patent due to the choice of weave pattern and machine direction MD yarns per unit width, all of the binder yarns feature long lengths of unbound yarn floating between the paper side and wear side fabrics such that fabric thickness, water carry and stability may be problematic. Furthermore the low level of binder-warp interlacings in each layer, and the preference for polyester binder material, fails to address delamination issues.
EP 1,000,197A ('197 patent) and divisional patent EP 1,158,090A ('090 patent) both disclose triple layer fabric in which the paper side weave is obtained by the interweaving of paper side machine direction (MD) or warp yarns with both paper side weft yarns and interchanging pairs of weft yarns. In addition to each interchanging weft pair providing a single continuous weft path in the paper side fabric, each pair member also acts to bind the paper side and wear side fabrics together.
While commercial embodiments according to the '197 patent and divisional '090 patent have been found to give some benefits such fabrics utilized the same MD yarn diameter and yarns per unit width as the '315 patent, and thus were also found to possess high thickness such that water carried within the fabric void space may, near the end of the paper machine's sheet forming zone, rewet the paper sheet resulting in decreased machine efficiency. EP 1,273,698A seeks to resolve this issue for the same weave patterns disclosed in the '197 and '090 patents by utilizing greater numbers of thinner MD and cross direction CD yarns than were used hitherto such that thinner structures with less void space are provided. While this approach is helpful in resolving the so-called “sheet rewet” issue it creates a new problem in that the finer fabric has reduced CD bending stiffness and consequently the less stable fabric has a decreased ability to minimize sheet basis weight profiles.
The problem of fabric bending stiffness in a triple-layer fabric containing interchanging weft yarn pairs was addressed to some extent by Kufferath in the WO 02/14601 publication (the '601 publication), wherein
According to one aspect of the invention, triple-layer fabrics are provided with enhanced cross-machine-direction stiffness.
According to another aspect of the invention, there is provided a triple-layer fabric having a desirably low void volume and water carry potential.
According to a further aspect of the invention, there is provided a triple-layer fabric with enhanced fabric delamination resistance between a paper side and wear side layer of the fabric.
More specifically, according to the invention, there is provided a relatively fine and thin fabric with reduced void volume and water carry potential.
According to yet another aspect of the invention, there is provided a triple layer fabric with excellent wear side abrasion resistance.
More specifically according to the invention, there is provided a triple layer fabric having a desirably low void volume and water carry potential in combination with good delamination resistance and CD bending stiffness.
The above and other objects of this invention are obtained in “binder-top” composite fabrics. The meaning of “binder-top” will be explained in detail later herein.
In accordance with one embodiment of this invention, a multi-layer forming fabric has a paper side warp layer and a machine side warp layer, the fabric comprising at least one set of paper side wefts, at least one set of machine side wefts and at least one pair of interchanging weft yarns, the members of each interchanging weft pair together forming one continuous weft path on the paper side and all of said interchanging weft pair members interweaving with at least one paper side warp and, in at least one interchanging weft pair, only one of the members interweaving with at least one machine side warp. In other words, at least one interchanging weft yarn pair includes one weft yarn that, within each weave repeat, forms part of the continuous weave pattern in the paper side layer, and then moves out of the paper side layer adjacent one side of a paper side warp transition yarn to float between the paper side and wear side layers before re-entering the paper side layer. This latter weft yarn does not bind to any warp yarns in the wear side layer and is the “top” weft yarn of the binder-top interchanging yarn pairs. The other yarn of the interchanging top weft yarn-binder yarn pair is a binder yarn that moves into the paper side layer on the side of the paper side warp transition yarn opposite the side where the interchanging top weft yarn of the pair moves out of the paper side layer to thereby maintain the continuity of the continuous weave pattern in the paper side layer in the location overlying the region where the interchanging top weft yarn floats between the paper side and wear side layers. The binder yarn of the pair then moves out of the paper side layer on the side of a second paper side warp transition yarn opposite the side where the top weft yarn re-enters the paper side layer, and, in the region underlying the segment where the interchanging weft yarn binds to the warp yarns of the paper side layer, the interchanging binder yarn binds to at least one warp yarn of the wear side layer to bind together the paper side and wear side layers. In accordance with the broadest aspect of this invention, the fabric is not required to be a forming fabric.
In accordance with another aspect of this invention, the paper side layer of the fabric comprises only paper side warp yarns and interchanging weft yarn pairs, of which at least one pair comprises one binder member and one top weft member, such that there are no additional top weft yarns present. In other words, interchanging yarn pairs form all of the continuous weft paths in the paper side layer and at least one of the interchanging yarn pairs is a top weft-binder yarn pair to also bind to bottom warp yarns to hold together the paper side and wear side layers.
As used throughout this application, “intrinsic binder yarn/top weft yarn pairs,” or simply “binder-top” pairs, means a pair of interchanging yarns wherein one yarn of the pair, namely the binder yarn, forms the weft path in the paper side surface of the paper side layer in a first segment of each repeat of the weave pattern and then drops down to encircle at least one warp yarn in the machine side layer in a region underlying an adjacent second segment in the paper side layer. The intrinsic top weft yarn of the binder-top pair forms the weft path in a second segment in the paper side layer within each repeat of the weave pattern that is not occupied by the binder yarn of the pair, and then drops out of the paper side layer to float between the paper side layer and machine side layer in the first segment within each repeat of the weave pattern, without in any way binding the paper side layer to the machine side layer within the weave repeat. The resulting float, if it extends between two or more adjacent pairs of top and bottom warp yarns, is defined herein as a stiffening section. The binder yarn of the binder-top pair may also provide stiffening sections by interlacing with spaced apart wear side fabric MD yarns and floating between at least two adjacent pairs of top and bottom warp yarns between such interlacings. A “top weft yarn/binder yarn pair” is illustrated in FIG. 2(b) of International Publication No. WO 02/14601, the subject matter of which is incorporated herein by reference.
In particular embodiments, the multi-layer forming fabric has a top member stiffening section length between 5 and 9 warp pairs and a length of the binder member stiffening section interlacing with machine side warp yarns between 2 and 4 warp pairs.
Reference throughout this application to “intrinsic interchanging weft binder yarns” or “interchanging weft binder yarns” means paired yarns, each of which forms a part of the weave structure in at least the paper side layer of the composite fabric and also binds the paper side layer and machine side layer together. Thus, each intrinsic weft binder yarn of each pair of first and second intrinsic weft binder yarns provides two functions within each repeat of the weave pattern. One function is to contribute to the weave structure of the paper side surface of the paper side layer, and the second function is to bind together the paper side layer and the machine side layer.
In accordance with one of the preferred embodiments of this invention, at least 50% of the pairs of intrinsic interchanging yarns, and most preferably 100% of such pairs, are intrinsic, interchanging binder-top yarn pairs providing a minimum of 2 segments within each weave repeat, as described above. However, it is within the scope of this invention to also include within the fabrics other types of intrinsic interchanging weft yarn pairs other than binder-top yarn pairs, such as “intrinsic binder yarn/binder yarn pairs” (hereinafter binder-binder) in combination with the plurality of intrinsic, interchanging binder-top yarn pairs. It also is within the scope of the broadest aspects of this invention to provide intrinsic, interchanging binder-top yarn pairs that constitute less than 50% of the pairs of intrinsic interchanging yarns.
In accordance with certain preferred embodiments of this invention, the ratio of paper side to wear side warp yarn diameter is in excess of 0.75 such that when relatively fine paper side MD yarns are used the fabric thickness is suitably low.
In accordance with certain preferred embodiments of this invention the cover factor of the paper side warp yarns/cm unit width (calculated by multiplying yarn diameter by the number of yarns/cm by 10) is in excess of 40.0% such that when relatively fine paper side MD yarns are used, the initial drainage through the fabric may be adequately controlled. The fabric may be woven such that the effective paper side to machine side CD ratio is 2:1.
In accordance with certain preferred embodiments of this invention, the paper side and wear side warp diameter combinations are selected from the group of: 0.11 mm paper side and up to 0.15 mm wear side; 0.12 mm paper side and up to 0.17 mm wear side; 0.13 mm paper side and up to 0.19 mm wear side; 0.14 mm paper side and up to 0.19 mm wear side; 0.15 mm paper side and up to 0.20 mm wear side; and [[&]] 0.16 mm paper side and up to 0.22 mm wear side.
In accordance with certain preferred embodiments, the paper side MD yarns/cm unit width when using 0.12 mm paper side MD yarns is in the region of 35 to 40 yarns/cm; when using 0.13 mm paper side MD yarns is in the region of 30 to 35 yarns/cm; when using 0.14 mm paper side MD yarns is in the region of 30 to 35 yarns/cm; when using 0.15 mm paper side MD yarns is in the region of 28 to 33 yarns/cm and when using 0.16 mm paper side MD yarns is in the region of 26 to 33 yarns/cm.
Details of various preferred embodiments of the invention will now be described in connection with the following drawings, wherein:
In describing various embodiments of the invention, reference may be made to a number of features, which are defined below, prior to describing the various embodiments of this invention.
a) Interchanging Weft Yarn Segments
The two members, or yarns, of an interchanging weft pair interchange to provide one continuous weft path on the paper side fabric, or layer and one or both of the pair may also bind to wear side fabric MD yarn(s). Each part of the paper side weft path made by one of the pair members is defined as a “segment.” The segment length is defined as the number of paper side layer warps in an adjacent preceding transitional region plus the paper side warps with which the interchanging yarn weaves under or over before entering the next transitional region. In the fabrics of the invention the yarns of each interchanging yarn pair typically transition, or move in/out of the paper side layer alongside opposite sides of common paper side warp yarn(s), such that the two members of the interchanging pair actually cross each other beneath such warp yarn(s). The common paper side warp yarn(s) is (are) referred to as a “transitional” (warp) yarn or yarns. In the most preferred embodiments the common paper side warp yarn is a single, top warp yarn, and the yarn of an interchanging yarn pair that is weaving with the top warp yarns in the paper side layer upstream of that transitional warp yarn will move out of the paper side layer adjacent the upstream side of the transitional warp yarn and the other yarn of the pair will move into the paper side layer adjacent the other, or downstream side of the transitional warp yarn. The two interchanging yarns cross each other in a region generally underlying the transitional warp yarn. The upper surface of each such transitional warp yarn may be referred to as a transition point, even though the interchanging weft pair transition (i.e., crossover) occurs under these yarns. In instances where the interchanging yarn pair transitions between contiguous paper side warp yarns, instead of under one or more paper side warp yarns, then the transition point is considered to be located equidistant to both of the contiguous paper side warp yarns. It should also be noted that the further terms “interchange point(s)” and “interchange warp(s)” as used within this application have identical meanings to “transition point(s)” and “transitional warp(s)” respectively. It also should be noted that such interchanging points and interchanging warps are included in prior art structures, such as the structures disclosed in the earlier identified Ward '197 patent, which already has been fully incorporated by reference herein.
As with the weave repeat of the prior art fabrics, embodiments shown herein repeat after two interchanging yarn segments. When a pair of first and second intrinsic, interchanging weft yarns includes two segments in the paper side layer within each repeat of the weave pattern, each yarn of that pair interchanges position into and out of the paper side layer two times within each such repeat. That is, a first yarn of the interchanging yarn pair is in the paper side layer in a first segment to form part of the continuous top weave pattern in each repeat; is beneath the paper side layer in a region underlying a second segment where it may also bind to one or more bottom warp yarns or alternatively it may remain between the fabric layers, and then is in the paper side layer in a first segment of a new repeat of the weave pattern. The other, or second, yarn of the interchanging yarn pair is in the paper side layer in the second segment to cooperate with the first yarn of the pair to complete the continuous top weave pattern in each repeat of the weave pattern; is in the machine side layer underlying a first segment of the paper side layer to bind to one or more bottom warp yarns in a region underlying such first segment, and then is in the paper side layer in a second segment of an adjacent repeat of the weave pattern.
It is also possible to make multi-segment structures with 4 or more segments, as disclosed in co-pending provisional patent application No. 60/477,376, filed on Jun. 10, 2003, and incorporated herein by reference and attached hereto as Exhibit A.
b) Binder Internal Float Length
The binder yarn in each interchanging pair of yarns employed in multi-layer fabrics of this invention moves between one fabric layer and the other. Thus, at some stage, after binding with an MD yarn of a first fabric layer the binder yarn then floats between warp yarns of the respective fabric layers before entering the second fabric layer to bind with an MD yarn in the second layer. The distance between leaving the first fabric layer and entering the second fabric layer is specified in terms of pairs of MD yarns and is the binder's internal float length (or simply “float length”) e.g., for a binder float length equal to one, the binder passes below a warp of the upper fabric layer and above a warp of the lower fabric layer with both of said warp yarns being aligned and constituting one pair of MD yarns. Embodiments of this invention illustrated herein are fabrics with 1:1 ratio of top-to-bottom MD yarns. However, within the broadest scope of this invention MD ratios other than 1:1 can be employed, for example, 3:2 or 2:1. In such cases the binder will float between full or partial groups of warp yarns instead of between pairs.
Excessively long binder float lengths are not preferred because they may create a relatively large vertical distance, or gap, inside the fabric, i.e. between the paper side and machine side layers, such that the structure may carry and retain more water than desired during sheet formation. The carried water, in turn, may be discharged onto the sheet being formed at the end of the forming section, thus undesirably increasing the sheet moisture content. Preferred embodiments of the invention have binder float lengths of between 1 and 3.
c) Interchanging Yarn Stiffening Section
Each interchanging yarn may, after interlacing around a warp yarn on the outside of either fabric layer, return to and remain inside the fabric, i.e., between the two fabric layers, before making a further interlacing with another warp yarn of the same layer. In the paper side layer of certain fabrics of this invention the interchanging yarn pair provides long external CD orientated yarn floats while in other fabrics of the invention the interchanging yarns weave in a plain weave, i.e., such that they weave over and under single adjacent warp yarns of the paper side layer. However, an interchanging yarn stiffening section within the fabrics of this invention requires the interchanging yarn to remain inside the fabric for two or more adjacent warp yarns and to be bound on each end of the stiffening section with a warp yarn of the same fabric layer. In this manner, a straight section of yarn is provided to enhance fabric cross-machine-direction (CD) bending resistance. Furthermore, it may also be possible to reduce the internal float length of the binder yarn by creating a stiffening section through interlacing with wear side fabric MD yarns to ensure a minimal “layer gap” between the respective fabric layers. These features of the invention are desirable to minimize undesired sheet moisture content and profiles therein, respectively, and will be described in detail hereinafter with respect to various embodiments of this invention.
d) Locked/Unlocked Binder
This refers to the binder members of the interchanging weft pairs and more particularly to the binder knuckle positions on the wear side layer in relation to the interlacings of adjacent wear side fabric warp and weft (non-interchanging) yarns. Where a binder of an interchanging yarn pair makes a knuckle under a yarn, or contiguous yarns, of the wear side layer and said knuckle is bordered on both sides by the adjacent warp yarns of the wear side layer interlacing with non-interchanging bottom weft yarns then said binder knuckle is classified as “locked” into position because the adjacent yarns will not allow that binder knuckle to move from its position, either in fabric manufacture or in end use of the fabric. Where the binder knuckle is not so bordered on both sides by MD-CD interlacings then it is classified as “unlocked.” Both unlocked and locked binder knuckle positions are included in embodiments of this invention.
In order to better understand the present invention, a prior art, 20 shaft fabric disclosed in Ward U.S. Pat. No. 5,437,315 will be briefly described in connection with
As can be seen in
It is clear from
Specifically, in each weave repeat, binder weft yarn I4 floats between four adjacent top and bottom warp pairs 19-20, 1-2, 3-4 and 5-6 before binding to top warp yarn 7, and then floats between three adjacent top and bottom warp pairs, 9-10, 11-12 and 13-14 before binding to adjacent bottom warp yarns 16 and 18. Long internal binder yarn paths, or floats, are known to contribute to undesirably high fabric thickness and also can move quite freely, thereby resulting in significant binder wear due to contact of the weft yarn with the inside of the two fabric layers as the composite structure travels around the paper machine.
The preferred embodiments of '315 also use a relatively low number of MD yarns in each layer such that distances between paper side yarns, and thus binder float length, are further extended.
Referring to
Alternate pairs of binder-top weft yarns 42a, 46a, 50a, 54a and 58a are of the same general arrangement, as will be described in detail with respect to pair 42a. In pair 42a, binder yarn I3 (solid line) provides the shorter paper side segment of 4 paper side warp yarns 13, 15, 17 and 19 and binds in a locked position, to single wear side warp yarn 8 in the region underlying the longer segment of 6 paper side warp yarns 1, 3, 5, 7, 9 and 11 provided by the top weft yarn I4 (dotted line). In the second alternate binder-top pairs 42a, 46a, 50a, 54a and 58a the stiffening section length provided by the top weft yarn of the pair is reduced to 5 pairs of warp yarns, e.g., 13-14, 15-16, 17-18, 19-20 and 1-2 provided by I4 of pair 42a.
Thus, the fabric illustrated in
Referring to
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but always of 4 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 7 warp pairs in the region underlying the first segments such that the stiffening effect is increased by comparison to the first embodiment. For example, the top weft yarn I2 (solid line) of the binder pair 40b provides a second paper side segment with top warp yarns 9, 11, 13 and 15, and then floats between warp pairs 17-18, 19-20, 1-2, 3-4, 5-6, 7-8 and 9-10. As can be seen in
The fabric disclosed in
Table 1 shows some test data for a sample fabric according to
Table 1 shows the only significant difference is the enhanced CD bend stiffness of the invention, i.e., an almost 20% increase. Both sample fabrics utilized 0.12/0.15 mm paper side and wear side MD yarn diameter, respectively at approximately 76 MD/cm. CD and binder diameter were 0.13 mm and other suitable diameters include 0.10 mm, 0.11 mm, and 0.12 mm. The utilization of relatively high MD yarns/cm allows the weave to repeat in a very small area such that a relatively high number of binding points can be obtained to enhance delamination resistance.
Referring to
The top weft yarn of each of the interchanging binder-top weft yarn pairs provides a second paper side segment, but always of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments such that the stiffening effect is decreased by comparison to the previous embodiment. For example, top weft yarn I1 (dotted line) of the interchanging pair 40c provides a second paper side segment with paper side warp yarns 17, 19, 1, 3, 5 and 7, and then floats between the five warp pairs 9-10, 11-12, 13-14, 15-16 and 17-18. This same relationship exists for top weft yarn I4 of the interchanging pair 42c, as well as for all of the remaining interchanging pairs.
As in the fabric disclosed in
As in the previous 20 shaft embodiments, the fabric has 10 non-interchanging top weft yarns (T1-10), 10 non-interchanging bottom weft yarns (B1-10) and 10 pairs of binder-top weft interchanging yarn pairs. Both the top weft yarns T1-10 and bottom weft yarns B1-10 can provide the identical weave pattern with the top and bottom warp yarns, respectively, as the previously disclosed embodiments. The binder yarn of adjacent interchanging pairs binds to a single bottom warp yarn that shifts 2 warp yarns from the previous binder yarn. For example, binder yarn I2 of the pair 40c binds to bottom warp yarn 4. Binder yarn I3 of the interchanging pair 42c shifts over two bottom warp yarns to bind to bottom warp yarn 8. Similarly, the binder yarn of the next interchanging pair binds to bottom warp yarn 12; the binder yarn of the next interchanging pair binds to bottom warp yarn 16, etc.
Referring to
The top yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but always of 4 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 7 warp pairs in the region underlying the first segments such that the stiffening effect is increased by comparison to the first embodiment which had alternative stiffening sections of 5 and 7 warp pairs respectively. For example, top weft yarn I2 of the interchanging pair 40d provides a second paper side segment with 4 paper side warp yarns 9, 11, 13 and 15 and then floats between the 7 warp pairs 17-18, 19-20, 1-2, 3-4, 5-6, 7-8 and 9-10. This same relationship exists for the top weft yarns in all of the interchanging yarn pairs, as can be seen in
The fabric disclosed in
Referring to
The top yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but always of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. For example, top weft yarn I1 (dotted line) of the interchanging binder-top weft yarn pair 40e provides a second paper side segment with the 6 paper side warp yarns 1, 3, 5, 7, 9 and 11, and provides a stiffening section of 5 warp pairs 13-14, 15-16, 17-18, 19-20 and 1-2. As can be seen in
The fabric disclosed in
Referring to
The top yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but always of 4 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 7 warp pairs in the region underlying the first segments such that the stiffening effect is increased by comparison to the first embodiment. For example, the top weft yarn I2 of the interchanging pair 40f provides a second paper side segment with 4 paper side warp yarns 5, 7, 9 and 11, and also floats between the 7 warp pairs 13-14, 15-16, 17-18, 19-20, 1-2, 3-4 and 5-6. This same relationship exists for all of the top weft yarns in the other pairs of interchanging yarns.
Regarding the internal binder float lengths in
The fabric disclosed in
Referring to
The top weft yarn of the alternate, interchanging binder-top weft yarn pairs 40g, 44g, 48g, 52g and 56g provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of example, the top weft yarn I1 (dotted line) of the interchanging pair 40g provides a second paper side segment with the 6 paper side warp yarns 9, 11, 13, 15, 17 and 19, and also floats between the 5 warp pairs 1-2, 3-4, 5-6, 7-8 and 9-10.
The above alternating pairs of interchanging yarns, which have the above described weave relationship, alternate with interchanging pairs 42g, 46g, 50g, 54g and 58g. In these latter pairs of interchanging binder-top weft yarns the binder yarn provides the longer paper side segment of 6 paper side warp yarns and binds, in a locked position, to a first wear side warp yarn and also binds, in an unlocked position, to a second wear side warp yarn to provide additional delamination resistance, both bindings being located in the region underlying the shorter segment of 4 paper side warp yarns provided by the top yarn. By way of example, the binder yarn I4 (dotted line) of the interchanging pair 42g provides a paper side segment with the 6 paper side warp yarns 13, 15, 17, 19, 1 and 3, and binds in a locked position to bottom warp yarn 8 and in an unlocked position to bottom warp yarn 12.
In addition, in the second set of alternate binder-top pairs 42g, 46g, 50g, 54g and 58g the stiffening section length is increased to 7 pairs of warp yarns. By way of explanation, the stiffening section in the pair 42g is provided by the top weft yarn I3 (solid line) floating between warp pairs 13-14, 15-16, 17-18, 19-20, 1-2, 3-4 and 5-6.
In all of the interchanging binder-top weft pairs in this embodiment (
The fabric disclosed in
Table 2 shows the influence of the interchanging yarn pair material. In particular the shrinkage of the material has a strong influence on the resulting properties. In both samples made according to
Consequently it is demonstrated that when using interchanging yarns of the same polymer type it is possible to derive benefits due to selected yarn thermal shrinkage properties. The interchanging yarns of a pair can both be made with both using either high or low shrink yarns of the same polymer or the low and high shrink yarns can be mixed within a given interchanging yarn pair.
Note is also made of the relative fineness of the fabric samples with approximately 66 MD yarns/cm and MD diameter of 0.14/0.18 mm. It is expected that other desirable combinations of MD diameters (0.13/0.17) and CD diameters on paper side of 0.10 to 0.15 mm and binder diameters of 0.10 to 0.15 mm and MD yarns/cm (60-70/cm) would yield similar results
Referring to
In
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of further explanation, the top weft yarn I1 (dotted line) provides a second paper side segment with 6 paper side warp yarns 5, 7, 9, 11, 13 and 15, and floats between 5 warp pairs 17-18, 19-20, 1-2, 3-4 and 5-6 between binding to top warp yarns 15 and 7.
In all of the interchanging binder-top weft pairs in this embodiment the first and second warp yarns of the wear side fabric which are interlaced with the binder yarn are situated on either side of an intervening wear side fabric warp yarn, in the same manner as previously described in connection with the fabric shown in
The fabric disclosed in
Referring to
In
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of further explanation, the top weft yarn I1 (dotted line) provides a second paper side segment with 6 paper side warp yarns 1, 3, 5, 7, 9 and 11, and floats between 5 warp pairs 13-14, 15-16, 17-18, 19-20 and 1-2 between binding to top warp yarns 11 and 3.
This embodiment (
The fabric disclosed in
Table 3 contrasts sample fabric of the invention (according to
Referring to
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but of 8 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 3 warp pairs in the region underlying the first segments. By way of further explanation, top weft yarn I1 (dotted line) provides a paper side segment with 8 paper side warp yarns 1, 3, 4, 7, 9, 11, 13 and 15, and then floats between 3 warp pairs 17-18, 19-20 and 1-2.
As noted above, in all the interchanging binder-top weft pairs in this embodiment of the invention the first and second bottom warp yarns of the wear side fabric which are interlaced with the binder yarn are situated on either side of four intervening wear side fabric warp yarns to thereby provide an additional stiffening yarn section.
The fabric disclosed in
Table 4 contrasts sample fabric of the invention (according to
Referring to
In
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of further explanation, the top weft yarn I1 (solid line) provides a second paper side segment with 6 paper side warp yarns 19, 1, 3, 5, 7, and 9, and floats between 5 warp pairs 11-12, 13-14, 15-16, 17-18 and 19-20 between binding to top warp yarns 9 and 1.
This embodiment (
The fabric disclosed in
Referring to
The binder yarn of a first pair of interchanging binder-top weft yarn pairs provides a first paper side segment of 4 paper side warp yarns, and binds in a locked position, to a single bottom warp yarn in regions underlying the second segments. By way of further explanation, binder yarn I2 (solid line) of the interchanging pair 40L provides a first paper side segment of 4 paper side warp yarns 13, 15, 17 and 19, and binds in a locked position to bottom warp yarn 8.
The top yarn of the first interchanging binder-top weft yarn pairs provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of further explanation, top weft yarn I1 (dotted line) of interchanging binder pair 40L provides a paper side segment of 6 paper side warp yarns 1, 3, 5, 7, 9 and 11, and then floats between the 5 warp pairs 13-14, 15-16, 17-18, 19-20 and 1-2, between binding to top warp yarns 11 and 3.
The above-described weave arrangement is provided in alternate pairs of binder-top weft interchanging yarns. These latter interchanging yarn pairs alternate with yarn pairs having a different arrangement, as is exemplified by yarn pair 42L.
The binder yarn in the interchanging yarn pair 42L, and in the other yarn pairs that alternate with the first group of yarn pairs, provides the longer paper side segment of 6 paper side warp yarns and binds in a locked position, to a single wear side warp yarn in the region underlying the shorter segment of 4 paper side warp yarns provided by the top weft yarn. In the second alternate binder-top pairs the stiffening section length provided by the top weft interchanging yarn is increased to 7 pairs of warp yarns. By way of example, the binder yarn I4 of the interchanging pair 42L provides the paper side segment with 6 paper side warp yarns 9, 11, 13, 15, 17 and 19, and binds to single bottom warp yarn 6 underlying the other paper side segment. The top weft yarn I3 has a stiffening section length of the 7 pairs of warp yarns 9-10, 11-12, 13-14, 15-16, 17-18, 19-20 and 1-2. As noted above, this embodiment provides a paper side to wear side effective CD ratio of 1:1 unlike the prior embodiments which all provided an effective CD ratio of 2 paper side paths: 1 wear side yarn.
By comparison to the prior embodiments, which had a 2:1 CD ratio, the fabric of
As with all embodiments,
Referring to
The embodiment shown in
The top weft yarn of the first set of alternating, interchanging binder-top weft yarn pairs provides a second paper side segment, but of 4 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 7 warp pairs in the region underlying the first segments. By way of example, top weft yarn i1 (solid line) of the interchanging pair 40m provides a second paper side segment with 4 paper side warp yarns 5, 7, 9 and 11, and the floats between 7 warp pairs 13-14, 15-16, 17-18, 19-20, 1-2, 3-4 and 5-6 between binding to top warp yarns 11 and 7.
The set of binder-top weft yarn pairs having the arrangement of 40m alternate with a second set of binder-top weft yarn pairs.
In the second set of binder-top weft yarn pairs the binder yarn provides the shorter paper side segment of 4 paper side warp yarns and binds in a locked position, to a single wear side warp yarn in the region underlying the longer segment of 6 paper side warp yarns provided by the top weft yarn. In the second set of alternating binder-top pairs the stiffening section length provided by the top weft yarn is decreased to 5 pairs of warp yarns. By way of example, binder-top weft yarn pair 42m is representative of the second set of alternating pairs. The binder yarn i4 (solid line) in this pair provides the paper side segment of 4 paper side warp yarns 11, 13, 15 and 17. The top weft yarn i3 (dotted line) of this pair provides a paper side segment of 6 paper side warp yarns 19, 1, 3, 5, 7 and 9, and floats between 5 pairs of warp yarns 11-12, 13-14, 15-16, 17-18 and 19-20.
This embodiment of the invention provides a paper side to wear side effective CD ratio of 3:2 unlike the prior embodiments which provided an effective CD ratio of either 2:1 or 1:1. For an identical number of woven yarns, a 3:2 effective CD ratio will provide a significant increase in wear side yarns and the same number of paper side yarns as a 2:1 CD ratio fabric such that life potential is increased. This is because the 3:2 ratio fabric has less pairs of interchanging yarns which only give a single effective yarn path.
The top weft yarns all provide a plain weave pattern. The bottom weft yarns are a 5 shed repeat (as were all prior embodiments with the exception of
Regarding the internal binder floats in
Referring to
The binder yarn of each pair of interchanging binder-top weft yarn pairs provides a first paper side segment of 6 paper side warp yarns, and binds, in an unlocked position, to a first wear side warp yarn and also binds, again in an unlocked position, to a second wear side warp yarn to provide additional delamination resistance, both bindings being located in regions underlying the second segments. By way of example the binder yarn 12 (solid line) provides a first paper side segment of 6 paper side warp yarns 5, 7, 9, 11, 13 and 15, and then binds, in unlocked positions to bottom warp yarns 24 and 28.
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, but of 8 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 7 warp pairs in the region underlying the first segments. By way of example, top weft yarn I1 (dotted line) of the pair 40n provides the second paper side segment of 8 paper side warp yarns 17, 19, 21, 23, 25, 27, 1 and 3, and then floats between the 7 warp pairs 5-6, 7-8, 9-10, 11-12, 13-14, 15-16 and 17-18.
In all the interchanging binder-top weft pairs in this embodiment the first and second warp yarns of the wear side fabric which are interlaced with the binder yarn are situated on either side of an intervening wear side fabric warp yarn.
Variants on
Regarding the paper side transition points these still number two for each interchanging pair. However, it is now two for every 28 MD yarns and not for every 20 MD yarns as with prior embodiments, i.e., there is the possibility of reduced wiremark due to reduction in the transition points per unit area. This concept has been described in some detail in co-pending application Ser. No. 60/473,664, titled “High Shaft Fabrics” which was filed on May 23, 2003. The subject matter of this '664 application is herein fully incorporated by reference.
Referring to
The paper side wefts all form a plain weave pattern within each repeat. The wear side wefts employ an 8 shaft repeat and step three to the right relative to the immediately preceding wear side weft. To further explain, wear side weft B1 binds to bottom warps 2 and 18. The next succeeding wear side weft B2 steps three to the right relative to B1 and binds with bottom warps 8 and 24. The next succeeding wear side weft B3 steps three to the right relative to B2 and binds with bottom warps 14 and 30. This arrangement continues for the rest of the bottom weft yarns within the repeat.
The binder yarn of each pair of interchanging binder-top weft yarn pairs provides a first paper side segment of 8 paper side warp yarns, and binds, in an unlocked position, to a first wear side warp yarn and also binds, again in an unlocked position, to a second wear side warp yarn to provide additional delamination resistance, both bindings being located in regions underlying the second segments. By way of example, binder yarn 11 (solid line) of the interchanging pair 40p provides a first paper side segment of 8 paper side warp yarns 25, 27, 29, 31, 1, 3, 5 and 7, and then binds, in unlocked positions to bottom warp yarns 14 and 22.
The top weft yarn of the interchanging binder-top weft yarn pairs provides a second paper side segment, also of 8 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 9 warp pairs in the region underlying said first segments. By way of example, top weft yarn I2 (dotted line) of the interchanging pair 40p provides a second paper side segment with 8 paper side warp yarns 9, 11, 13, 15, 17, 19, 21 and 23, and then floats between the 9 warp pairs 25-26, 27-28, 29-30, 31-32, 1-2, 3-4, 5-6, 7-8 and 9-10 between binds to top warp yarns 23 and 11.
In all the interchanging binder-top weft pairs in this embodiment the first and second warp yarns of the wear side fabric which are interlaced with the binder yarn are situated on either side of 3 intervening wear side fabric warp yarns to thereby provide an additional stiffening yarn section. By way of example, the first and second bottom warp yarns 14 and 22, which are interlaced with the binder yarn I1 are situated on opposite sides of the 3 intervening wear side fabric warp yarns 16, 18 and 20. In this embodiment there is no reversal of the insertion order because each of the two paper side segments are of the same length, i.e., 9 paper side warp yarns in length. However, it is not a limiting feature of the invention that, where possible the segments must be of equal length, as, regarding the embodiment shown in
Still regarding segments of different length but in multi-segment binder-top embodiments it is feasible to provide at least one pair of interchanging binder-top yarns wherein each member of the pair provides two segments each of different lengths. This technique has been disclosed in co-pending application Ser. No. 60/477,376, titled Fabrics with Multi-Segment, Paired, Interchanging Yarns, filed on Jun. 10, 2003. The subject matter of this latter '376 is hereby fully incorporated by reference herein. In the two segment embodiments it is possible to vary segment lengths from one pair of interchanging binder-top yarns to another of the pairs. Benefits sought by this technique can include optimization of delamination resistance or stiffening segment or break up of transitional warp yarn twill lines.
In both multi-segment and 2 segment binder-top embodiments it is also possible to redistribute transitional warp yarn twill lines by placing a different number of paper side CD yarns between at least three adjacent pairs of interchanging binder-top yarns.
Returning to discuss
Referring to
Still referring to
The top weft yarn of the first interchanging binder-top weft yarn pair provides a second paper side segment, but of 6 paper side warp yarns, and floats between paper side and wear side fabrics to provide a stiffening section of 5 warp pairs in the region underlying the first segments. By way of example top weft yarn I4 (dotted line) provides a second paper side segment with 6 paper side warp yarns 1, 3, 5, 7, 9 and 11, and floats between the 5 warp pairs 13-14, 15-16, 17-18, 19-20 and 1-2.
The next binder-top weft yarn pair 46q, which is spaced from the preceding binder-top weft yarn pair 42q by an interchanging binder-binder pair 44q, has a different arrangement from the pair 42q. Specifically the binder-top weft yarn pair 46q includes a binder yarn 18 that provides a first paper side segment with 6 paper side warp yarns 9, 11, 13, 15, 17 and 19 and binds to a single bottom warp yarn 6, which is locked. The top weft yarn 17 of the pair 46q provides a paper side segment of 4 paper side warp yarns 1, 3, 5 and 7, and then floats between 7 pairs of warp yarns 9-10, 11-12, 13-14, 15-16, 17-18, 19-20 and 1-2.
The interchanging binder-top weft yarn pairs alternate with second pairs of interchanging weft yarns which are disposed as binder-binder interchanging weft pairs. In a first pair 40q of the binder-binder pairs a first binder yarn I1 (dotted line) provides the longer paper side segment of 6 paper side warp yarns 17, 19, 1, 3, 5 and 7 and binds in a locked position, to a single wear side warp yarn 14 in the region underlying the shorter segment of 4 paper side warp yarns 9, 11, 13 and 15 provided by the second binder member I2 (solid line) of the interchanging pair. This same arrangement exists for binder yarn I5 (dotted line) and I6 (solid line), there being no reversal of the yarns. The inclusion of interchanging binder pairs alternating with the two different types of binder-top weft yarns increases fabric delamination resistance. It is within the scope of the invention to vary the number and arrangement of interchanging binder-binder yarn pairs, as well as the two different types of binder-top weft yarn pairs.
Referring to
Referring to
Referring to
It should be understood that the binder-top weft yarn pairs 40r, 40s and 40t disclosed for use in fabrics of this invention can be employed as all of the interchanging yarns in the respective fabrics, or only some of the interchanging yarns in such fabrics. In accordance with the broadest aspects of the invention, the identified binder-top weft yarn pair can be employed only once in each repeat of the respective fabric. However, most preferably the identified binder-top weft yarn pair makes up all of the interchanging yarn pairs in the respective fabrics.
It also should be noted, that one or more binder-binder yarn pairs may be employed in the various embodiments of this invention, in addition to the embodiment of
Referring to
The first row of the summary chart, following the header row, includes structural features of the embodiment disclosed in
The second column specifies that the fabric of
The third column specifies that the effective ratio of cross-direction (CD) paper side (PS) yarns to wear side (WS) yarns is 2:1.
The fourth column specifies that the interchanging top weft yarns of the interchanging top weft-binder yarn pairs alternate between providing two paper side (PS) knuckles and three paper side knuckles.
The fifth column specifies that the interchanging binder yarns of the pairs of interchanging top weft-binder yarn pairs alternate between providing three paper side (PS) knuckles and two paper side knuckles. Thus when the interchanging top weft yarn provides two paper side knuckles the binder yarn of the pair provides three paper side knuckles, and vice versa.
The sixth column specifies that the segment lengths of the interchanging yarn pairs are reversing in the disclosed embodiment.
The seventh column specifies that the binder yarn of each of the interchanging top weft-binder yarn pairs is always inserted first.
The eighth column specifies that the length of the stiffening sections provided by interchanging top weft yarns alternate between 7 warp pairs (when the top weft yarn forms 2 paper side knuckles) and 5 warp pairs (when the top weft yarn forms 3 paper side knuckles).
The ninth column specifies that the binder yarns of the interchanging yarn pairs do not provide any stiffening sections.
The tenth column specifies that the binder yarns of the interchanging yarn pairs do not interlace with multiple wear side warp yarns within each repeat. That is the binder yarns interlace with only a single wear side warp yarn within each 20 shaft repeat.
Based on the above explanation, the various features of the other embodiments of this invention would be readily understood by a person skilled in the art. Therefore, no further explanation is provided herein.
It also should be noted that the yarn diameters of the paper side warp yarns and the wear side warp yarns can be varied, and preferably are different from each other. The most preferred relationships of the diameters of the paper side warp yarns and the wear side warp yarns is disclosed in the Summary of the Invention and will not be repeated herein for purposes of brevity. Suffice it to state that the specified yarn diameters and their disclosed relationship to each other can be employed in all of the various disclosed embodiments of this invention.
Finally, although reference has been made to the yarns of the various disclosed embodiments having diameters, it is to be understood that the cross sectional shape of any or all of the yarns used in any of the embodiments may be of non-circular profile e.g. ovate, rectangular, square, bi-nodal, etc.
The present application claims priority under 35 U.S.C. 119(e) of U.S. provisional Application 60/494,875, filed Aug. 13, 2003.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP04/51794 | 8/13/2004 | WO | 00 | 1/25/2006 |
| Number | Date | Country | |
|---|---|---|---|
| 60494875 | Aug 2003 | US |
