Patent Application
20060105660
The present invention is directed to paper machine clothing. The invention is directed particularly to woven paper machine clothing for forming and drying paper webs.
Paper machine clothing is well known in the art of papermaking. The paper machine clothing may comprise a support structure woven from metal or polymeric filaments. The intersection of filaments in the weave of the support structure may result in void spaces near the point of contact between intersecting filaments. These void spaces may harbor moisture and/or fiber fines. The presence of moisture and/or fiber fines in the void spaces may adversely impact the efficiency of the forming and drying processes involving the clothing.
The void spaces may become at least partially filled with water during the forming process. The combination of the embryonic web material and the clothing may contain additional water due to the water present in the void spaces. The additional water may require the expenditure of additional energy to remove the water from the clothing during the drying process.
The presence of fiber fines in the void spaces may impact the service life of the clothing. Fiber fines may be abrasive with respect to the clothing filaments. The motion of the clothing in the papermaking process may result in relative motion between the intersecting filaments. This relative motion may facilitate abrasion of the filaments by fiber fines present in the void spaces. Such abrasion may reduce the useful service life of the paper-machine clothing.
The presence of fines in the void spaces may increase the need to clean the clothing. The clothing may be cleaned by showering it with water. This cleaning requirement may require additional process water. Reducing the void spaces of the clothing and the attendant sanitation requirements may reduce the volume of water required for the process as a whole.
Paper machine clothing has been disclosed wherein the void spaces have been eliminated. In one example, the woven paper-machine clothing was heated to a temperature sufficient to cause the periphery of the filaments of the woven structure to melt and flow together. The clothing was subsequently cooled yielding clothing substantially devoid of the aforementioned void spaces. The intersecting filaments of resulting clothing fuse each to the other at the points of intersection. This fusion of the filaments may reduce the possible relative motion of the filaments as the paper machine clothing moves through the paper making process.
The present invention provides a woven support structure having reduced filament intersection voids that retains the capacity for relative motion of the woven filaments at the intersections of the filaments.
Paper-machine clothing comprising a woven structure having reduced void spaces at the intersection of the woven filaments in described herein. In one aspect of the invention the paper-machine clothing comprises a set of first filaments interwoven with a set of second filaments. At least one first filament contacts at least one second filament at an intersection point defining void spaces between the set of first filaments and the set of second filaments. The clothing further comprises a filling component that substantially fills the void spaces. The filling component adheres to at most one of the set of first filaments and the set of second filaments.
In another aspect of the invention, the woven clothing comprises a set of first filaments wherein at least one first filament comprises a periphery comprising a first component. The paper-machine clothing further comprises a set of second filaments, at least one second filament comprising a periphery. The second filaments interwoven and intersecting with the first filaments in a weave. The first component may flow and substantially conform to the periphery of the second filament at the intersection of the first filament and second filament in the weave. The first filament and the second filament are not bonded to each other at the intersection.
In another embodiment, the invention additionally comprises at least one deflection member defining at least one deflection conduit. The deflection conduit may provide a path for a fluid to pass through the paper-machine clothing.
While the claims hereof particularly point out and distinctly claim the subject matter of the present invention, it is believed the invention will be better understood in view of the following detailed description of the invention taken in conjunction with the accompanying drawings in which corresponding features of the several views are identically designated and in which:
As used herein weft filaments refers to filaments generally running across the length of a woven structure. For paper-machine clothing comprising a woven structure, weft filaments refers to filaments woven in the cross-machine direction.
As used herein, warp filaments refers to filaments running along the length of a woven structure. For paper-machine clothing having a woven structure, warp filaments refers to filaments woven in the machine direction.
As used herein reactive filaments refers to filaments comprising a component material as at least a portion of the periphery of the filament wherein the component material is more susceptible to softening due to an external environmental condition than the material comprising the periphery of a non-reactive filament.
The discussion that follows is in terms of the intersection of a warp filament with a weft filament. One of skill in the art understands that the clothing of the invention may comprise a plurality of such intersections between warp filaments and weft filaments.
As shown in
The void spaces 300 at any particular intersection of a warp filament 242 and weft filament 241, may be considered the spaces bounded by the filaments and a set of imaginary planes. This set of planes may comprise two pairs of planes. A first pair of planes defined as perpendicular to the plane of the clothing and perpendicular to the weft filament 242. One plane of the first pair intersects the peripheral cross section of the warp filament at a point furthest to the left of a warp filament cross-sectional bisector. The other plane of the first pair intersects the warp filament peripheral cross-section at a point furthest to the right of a warp filament cross-sectional bisector.
Similarly, a second pair of planes is defined as perpendicular to the plane of clothing and perpendicular to the warp filament 242. One plane of the pair intersects the peripheral cross section of the weft filament 241 at a point furthest to the left of a weft filament peripheral cross-sectional bisector. The other plane of the-pair intersects the weft filament peripheral cross-section at a point furthest to the right of the weft filament peripheral cross-sectional bisector.
As shown in
In one embodiment the filling component 400 does not adhere to either the warp filament 242 or the weft filament 241. In this embodiment, the filling component 400 may at least partially encircle the intersection of the warp filament 242 and the weft filament 241. The warp filament 242 and weft filament 241 may move independently of the filling component 400.
In one embodiment the filling component 400 may adhere to either the warp filament 242 or the weft filament 241. As an example, the filling component 400 may adhere to the warp filament 242. In this example, the weft filament 241 may be free to move independently of the warp filament 242 and the filling component 241. The warp filament 242 may have surface energy and/or other characteristics that differ from those of the weft filament 241. These characteristic differences may predispose the filling component to selectively adhere to the warp filament 242.
In one embodiment the filing component 400 comprises a powder applied to the clothing 219, to one of the warp filaments 242, or the weft filaments 241. The clothing 219 may be heated after the application of the powder such that the powder melts. Without being bound by theory, applicants believe that the melted powder may flow into and substantially fill the void spaces 300 due to capillary forces. The powder may be selected such that the melted powder will harden and adhere to at most one of the warp filaments 242 or weft filaments 241.
In another embodiment, the filling component 400 may comprise a portion of an emulsion or dispersion. The filling component 400 of this embodiment may be selected with regard to the surface energies of the warp filaments 242 and weft filaments 241 such that the emulsion or dispersion will only wet one of the two respective filaments. The filling component portion of the emulsion or dispersion may substantially fill the void spaces 300. The carrier fluid or solvent may subsequently be evaporated or otherwise driven off leaving the filling component 400 substantially filling the void spaces 300. The filling component 400 may cured such that the filling component 400 adheres to at most one of the warp filaments 242 or weft filaments 241.
Exemplary filling components 400 for this embodiment include, without being limiting, polyesters, polyurethanes, polyacrylates, methylacrylates, polyvinyl ethers, polyvinyl alcohols, and combinations thereof. Exemplary solvents may include, without being limiting, methanol, ethanol, water, isopropanol, tetrahydrofuran, ethers, and mixtures thereof.
In another embodiment, the filling component 400 may comprise a fluid that is applied to the clothing 219. The filling component may flow into and substantially fill the void spaces 300. The filling component may be partially removed by passing a second fluid through the clothing 219 with sufficient energy to remove some of the filling component 400 but with insufficient energy to overcome the capillary forces acting upon the filling component 400 substantially filing the void spaces 300. The fluid filling component 400 may then be hardened by a reaction with a third fluid or through the exposure of the filling component 400 to activating radiation, or by heating the filling component 400.
In such an embodiment, the viscosity of the filling component fluid may be manipulated by altering the chemical formulation of the fluid or by altering the temperature of the fluid. This manipulation of the fluid viscosity may enable the removal of more or less of the fluid. The manipulation of the fluid viscosity may alter the force required to remove the fluid from the clothing. Fluid will be retained in the void spaces 300 unless the capillary forces acting upon the fluid are overcome. Manipulating the fluid viscosity may lower the force necessary to remove fluid from other portions of the clothing 219 without a corresponding lowering of the capillary forces acting upon the fluid. In such circumstances the removal of the fluid from substantially all of the clothing except the void spaces 300 may be accomplished.
In another embodiment the filling component may comprise a portion of one of the warp filaments 242 or weft filaments 241. As an example illustrated in
In one embodiment, the tension of the weave may yield a significant pressure between the warp filament 242 and the weft filament 241. This pressure may reduce the temperature at which the component material 110 softens and flows to substantially fill the void spaces 300. The component material 110 may soften and flow at a temperature below the nominal melting point of the component material 110.
In the embodiment shown in
In another embodiment the warp filament 242 may comprise a component material 110 comprising at least a portion of the periphery of the warp filament 242. In this embodiment, the component material 110 may be selected such that the component material 110 will soften and flow in the presence of a particular type of solvent and may subsequently be hardened with the removal of the solvent, by exposure to thermal energy or exposure to activating radiation. The softened component material 110 may flow into and substantially fill the void spaces 300 of the clothing 219. In one such embodiment, the weft filaments may be selected such that the periphery of the weft filaments 241 is resistant to the action of the solvent and also such that the softened and subsequently hardened component material 110 will not adhere to the weft filament 242.
In the above described embodiments, the non-reactive woven filaments—the weft filaments 241 in embodiments wherein the component material that softens and flows comprises a portion of the warp filaments 242, and the warp filaments 242 in any embodiment wherein the component material that softens and flows to fill the void spaces 300 comprise a portion of the weft filaments 241—may comprise monofilaments, multi filaments or a combination of these. The non-reactive woven filaments may comprise non-reactive bi-component filaments. Non-reactive bicomponent filaments may be selected such that no portion of the periphery of the filaments will adhere to the reactive filaments.
The reactive bi-component filaments in any of the above described embodiments may comprise a concentric sheath—core structure, an eccentric sheath core structure, a side by side structure, a pie wedge structure, a hollow pie wedge structure, an islands—sea structure, or a three islands structure as each of these structures is known in the art of bi-component fibers. As an example, illustrated in
Suitable bicomponent fiber materials include, without being limiting, combinations of co-polyester/poly(ethylene terephthalate), polyamide/poly (ethylene terephthalate), polyamide/polyamide, polyethylene/poly (ethylene terephthalate), polypropylene/poly(ethylene terephthalate), polyethylene/polyamide, polypropylene/polyamide, thermoplastic polyurethane/polyamide and thermoplastic polyurethane/poly(ethylene terephthalate).
As an example, weft filaments comprising bicomponent filaments having a poly(ethylene terephthalate) sheath surrounding a polyphenylene sulfide core may be interwoven with warp filaments comprising a polyphenylene sulfide sheath surrounding a poly(ethylene terephthalate) core.
Either of the warp filaments 242 or the weft filaments 241 may comprise a material opaque to at least a portion of the electromagnetic spectrum. Opaque filaments may at least partially block the transmission of actinic radiation through the clothing 219.
In one embodiment, the clothing 219 may comprise a single layer of woven filaments. In one such embodiment the single layer of woven filaments may comprise multiple layers of warp filaments 242 interwoven with a single layer of weft filaments 241. In another such embodiment, the single layer of woven filaments may comprise multiple layers of weft filaments 241 interwoven with a single layer of warp filaments 242. In yet another such embodiment, the single layer of woven filaments may comprise multiple layers of warp filaments 242 interwoven with multiple layers of weft filaments 241. Each of these embodiments is considered to comprise a single layer of woven filaments. Each described embodiment comprises a single woven structure and may not be separated into distinctly different woven structures.
In contrast to clothing 219 comprising a single layer of woven filaments, the clothing 219 may comprise multiple layers of woven filaments that are joined together as is known in the art. In an embodiment comprising multiple layers of woven filaments, the clothing 219 may be separated into distinctly different woven layers by the removal or elimination of a portion of the clothing 219 that serves to join the multiple woven layers to each other.
Clothing 219 comprising multiple woven structures, or comprising multiple layers of warp and/or weft filaments, may also comprise additional void spaces between the stacked warp or weft filaments. The filling component of the invention may at least partially fill these void spaces.
In one embodiment, the stacked filaments may contact each other. In another embodiment small gaps may exist between the stacked filaments. In either embodiment the stacked filaments may comprise capillary spaces. The filling component may flow into and at least partially fill the void spaces. At least partially filling these void spaces may reduce the energy and sanitation requirements associated with the clothing. Partially or substantially filling these void spaces may be accomplished without deleteriously reducing the air flow capacity of the clothing 219.
The reactive filaments and non-reactive filaments of the clothing 219 may each comprise a longitudinal cross-section and a radial cross-section. A longitudinal cross-section is considered to be a planar section taken along the length of the filament. A radial cross-section is considered to be a planar section taken perpendicular to the length of the filament. In one embodiment the cross sections of the reactive filaments may change as the component material of the reactive filament softens in response to the application of heat, exposure to a solvent, or other activating means. The softened component material may flow to occupy the void spaces at the intersection of the reactive filament and the non-reactive filament. The flow of the component material into the void spaces may alter the radial and/or longitudinal cross-sections of the reactive filaments such that one or more of the reactive filament cross-sections substantially conform to the cross-sections of the non-reactive filament.
In another embodiment, each of the warp filaments 242 and weft filaments 241 comprise reactive filaments. In this embodiment, the warp and weft filaments 242, 241, react to the application of heat, the exposure to a solvent, or other activation means and a portion of the periphery of each filament softens and flows. In this embodiment, the component materials of the warp filaments 242 and the weft filaments 241 may be selected such that the softened component materials do not generally mix together. In this embodiment, the component materials of the warp filaments 242 and weft filaments 241 may be selected such that they do not adhere each to the other. The component materials 110 of the warp filaments 242 of this embodiment may further be selected such that the softened component materials 110 do not adhere to the weft filaments 241. Similarly the component material 210 of the weft filament 241 may be selected such that the softened component material 210 of the weft filament 241 does not adhere to the warp filament 242.
As used herein, filaments not adhering each to the other or component materials not generally adhering to non-reactive filaments means that there is no chemical reaction between the non-adhering components resulting in a bonding of the components each to the other.
In any of the above described embodiments, the activation of the component material of bicomponent filaments may be accomplished without a substantial reduction in the air permeability of the woven structure. The component material may be activated such that the component softens and flows sufficiently to substantially fill the void spaces created by the filament intersections in the weave pattern. Filling the void spaces may not substantially reduce the air permeability of the woven structure.
Alternatively, the activation of the component material may yield a significant reduction in the air permeability of the woven structure. The component material may be activated such that the material partially or substantially fills the open areas of the woven structure thereby reducing the air permeability of the woven structure.
As illustrated in the embodiment shown in
The clothing of the invention may be used to support an embryonic web material. The presence of the deflection conduits may enable the deflection of the embryonic web material from the first surface into the deflection conduit. The deflection of the embryonic web material may provide a means of imparting a structure to the embryonic web material. The passage of fluid from the first surface to the second surface may facilitate the deflection of the embryonic web material into the deflection conduit. The fluid may comprise a gas, a liquid, or a combination of these.
As a non-limiting example, the clothing may support a fibrous embryonic web material. Air may be forced through the embryonic web and subsequently through the clothing. The movement of the air may force fibers of the embryonic web to deflect into the deflection conduits and may also remove moisture from the embryonic web. The air may also at least assist in removing moisture from the embryonic fibrous web and in the stabilization of the web.
As illustrated in
In another embodiment shown in
Suitable shapes for the openings 230 include, but are not limited to, circles, ovals, and polygons, with hexagonal shaped openings 230 shown in
In another embodiment shown in
In yet another embodiment shown in
Portions of the uppermost macroscopically monoplanar surface may at least partially overlap portions of lower macroscopically monoplanar surfaces forming cantilever portions.
In one embodiment shown in
In one embodiment, the deflection member 220 may be formed by applying a layer of a liquid photosensitive polymeric resin to the woven structure. The applied resin may be selected such that the resin cures from a liquid to a solid upon exposure to actinic radiation. The combination of the woven structure and the liquid resin may subsequently be exposed to actinic radiation. The resin may be selectively exposed by disposing a patterned mask adapted to selectively block the actinic radiation between the radiation source and the resin. The pattern of the mask selectively shields portions of the resin such that the shielded portions are not exposed to the activating radiation. The unexposed resin remains substantially unsolidified. The exposed resin portions cure to become substantially solid and at least semi-durable. The combination of the woven structure and the resin may subsequently be showered with a liquid, or subjected to a pressurized gas flow to remove unsolidified resin.
The removal of the unhardened resin may leave a pattern of cured resin mechanically coupled to the woven warp filaments 242 and weft filaments 241. The resin, warp filaments 242 and weft filaments 241 may be selected such that the cured resin adheres at most to one of the warp filaments and weft filaments. In one embodiment the cured resin adheres to either the warp filaments or the weft filaments. In another embodiment the cured resin adheres to neither the warp filaments nor weft filaments. The cured resin defines at least one deflection conduit as described above. The cured resin may comprise the deflection member as set forth above. The pattern of the mask may be selected to provide a pattern of cured resin that is substantially continuous, substantially semi-continuous, discrete or a combination thereof.
The clothing may comprise opaque filaments as described above. The presence of opaque filaments in the woven structure of the clothing 219 may impact the form of the cured resin. The opaque filaments may block the passage of actinic radiation through the woven structure and may shield at least a portion of the resin located beneath the opaque filaments from the actinic radiation. The shielded resin may remain unsolidified and may subsequently be removed from the clothing. As a result of the removal of at least a portion of this resin the second surface 224 of the deflection member may be irregular and may permit lateral fluid flow parallel to the plane of the clothing.
In one embodiment, additional macroscopic monoplanar patterned layers may be added by the repetition of the process described above. A liquid resin may again be applied to the clothing and subjected to actinic radiation through a patterned mask or otherwise subjected to a selective curing means. The successive applications and curing of a resin may yield multiple patterned structures at a single elevation or at multiple elevations.
In another embodiment, a macroscopically monoplanar patterned layer may be formed separately from the combination of the woven structure and any other macroscopically monoplanar layers and subsequently bonded to the combination using means known to those of skill in the art. In one such embodiment, a liquid resin may be applied to a textured forming surface and at least partially cured. This textured layer may subsequently be disposed in a face-to-face relationship with the clothing described above and bonded to the clothing. The bonding of the new layer and the clothing may be achieved via any means known in the art. Exemplary means include, without being limiting, the use of an appropriate adhesive that will bond to each of the clothing and textured layers, partially curing the resin of one or both of the textured layer or clothing and subsequently curing the remaining resin after the disposition of the textured layer in a face-to-face relationship with the clothing. The textured layer may be bonded to the clothing in such a manner as to register the pattern of the textured layer with the pattern of the resinous layer of the clothing. Alternatively, the texture of the new layer may be unregistered with respect to the pattern of the resinous layer of the clothing.
In another such embodiment, a layer of resin may be formed on a smooth surface. The resin may subsequently be exposed to actinic radiation at least partially occluded by a patterned mask as described above. The resin may be at least partially cured by this exposure. The uncured resin may subsequently be removed and the at least partially cured resinous layer may be disposed in a face-to-face relationship with the clothing and subsequently bonded to the clothing.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference, the citation of any document is not to be considered as an admission that it is prior art with respect to the present invention.
While particular embodiments of the present invention have been illustrated and described, it would have been obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of the invention.
