Abstract
Using electrostatic means, such as plasma, webs can be cut, and webs can be bonded together. A plasma is created and directed at an intervening poly or a nonwoven to sever the fabric, either continuously or intermittently, or to bond and sever two more material layers together.
Claims
1. A method for processing webs of material, the system comprising: providing at least one web of nonwoven material into a web processing system; supplying an anode and a cathode and a plasma between said anode and cathode; and passing said at least one web of material through said plasma to process said at least one web of nonwoven material by bonding individual fibers of said nonwoven web of material; creating a disposable product at least in part from said at least one web of nonwoven material.
2. A method according to claim 1, said method further comprising carrying at least one of said anode and said cathode on a first rotating body, carrying at least one of said anode and said cathode on a second rotating body and passing said at least one web through said plasma between said first and second rotating bodies.
3. A method according to claim 2, said plasma being generated between a first raised surface and a second raised surface, wherein the first raised surface is on one of said first and second rotating bodies and the second raised surface is on the other of said first and second rotating bodies.
4. A method according to claim 2, said method further comprising severing a discrete piece from said at least one web of nonwoven material and drawing said discrete piece into at least one of said first and said second rotating bodies.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIGS. 1-3 are side views of a plasma unit operating on a traveling web or webs;
[0027] FIG. 4 is a microscopic view of a web of material acted upon by plasma;
[0028] FIG. 5 is a microscopic view of a web of material intermittently acted upon by plasma;
[0029] FIG. 6 is a microscopic view of a web of material severed by plasma;
[0030] FIG. 7 is a microscopic view of a web of material showing individual non-woven fabric strands after being acted upon by plasma;
[0031] FIG. 8 is a perspective view of a pair of profiled die rolls with a generated plasma pattern generated between them acting upon a web of material, shown in closeup in FIG. 8A;
[0032] FIG. 9 is a perspective view of a profiled die roll and a smooth roll with a generated plasma pattern generated between them acting upon a web of material, shown in closeup in FIG. 9A;
[0033] FIG. 10 is an alternate embodiment of a pair of smooth profile electric die rolls with a generated plasma pattern generated between them acting upon a web of material, shown in closeup in FIG. 10A;
[0034] FIG. 11 is an alternate embodiment of a pair of smooth profile electric die rolls with a generated plasma pattern generated between them acting upon a web of material, the smooth profile electric die rolls executing a side cutout pattern;
[0035] FIG. 12 is an alternate embodiment of a pair of smooth profile electric die rolls with a generated plasma pattern generated between them acting upon a web of material, the smooth profile electric die rolls executing a cookie cutout pattern;
[0036] FIG. 13 is a side view of a vacuum assisted scrap material recovery system for recovering a cutout of a web.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0037] Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention.
[0038] Referring now to FIG. 1, a side view of a plasma unit 20 operating on a traveling web 10 or webs 10 is shown. Predetermined power is supplied between anode 20 and cathode 24, which creates plasma 26 with required heat. The size shape and location of the anode 20 and cathode 24 can be changed in order to locate or direct the plasma for intended action. They can be interchanged based on the specific conditions of plasma to be achieved. Cathode 24 is connected to the power source and located underneath the base plate 22. When a poly or a nonwoven materials is introduced atop the base plate 22, generated plasma between two electrodes (22 and 24) act upon the poly or nonwoven 10 as desired. If desired, the plasma field 26 can act to sever the fabric 10 (FIG. 3). If two layers of fabric 10 are placed on the base plate 22, which can be formed of polycarbonate, the plasma field 26 can be used to bond the two layers 10 together (FIG. 2), or to simultaneously bond the two layers 10 together and sever the layers along an intended severing line.
[0039] Referring now to FIG. 4, a microscopic view of two webs of poly material 10 acted upon by plasma 26 are shown. In this figure, it is seen that individual particles of the two poly layers 10 have become fused or welded together under the action of plasma.
[0040] Referring now to FIG. 5, a microscopic view of a web 10 of poly material is seen having been intermittently acted upon by plasma, and FIG. 6 shows a continuous severing of a poly web 10 severed by plasma.
[0041] Referring now to FIG. 7, a microscopic view of a web 10 of nonwoven material is shown, showing individual non-woven fabric strands after being acted upon by plasma.
[0042] It is noted that in the illustrated embodiments, a single web 10 is shown. However, laminates can be created by the addition of webs 10 of the same, similar, or dissimilar material layers. For instance, webs of elastic material can be combined (bonded) using electrostatic means if more than one web 10 is passed through the system.
[0043] Referring now to FIG. 8, one embodiment of the present invention is shown. A pair of profiled die rolls 120, and in particular a plasma pattern 26 generated between them, act upon a web passing between the rolls. In this embodiment, each roll has a patterned edge or profile 122 (which can take any shape), and as the two rolls rotate, the plasma follows the die profile between the two rolls, due to the high points of the die roll patterns 122 being the most proximal to one another (the smallest gap between the two rolls). The plasma 26 forms at this smallest gap point, where a web 10 is passed between the rolls 120, and the web 10 can be acted upon as desired in a controlled fashion.
[0044] Referring now to FIG. 9, in an alternate embodiment, a single profiled die roll 120 cooperates with a smooth roll 124, which can be formed of ceramic for example. In this embodiment, between the two rolls exists a controlled plasma generating gap location to control plasma pattern 26, and as the two rolls 120 and 124 rotate, the plasma pattern remains in place and follows the profile 122 on the profiled die roll. It is noted that plasma pattern 26 is referred to in this embodiment as being a single point location. In this embodiment, if a cross-machine direction cut is desired, the web 10 could be moved in a cross-machine direction, or skewed relative to machine direction as shown to approximate a cross-machine direction or transverse cut line. A radius-line of plasma could be created alternative to a single point plasma generation.
[0045] In the embodiments shown in FIGS. 8 and 9, different methods of web control can be used to guide the web 10. Web control could be applying vacuum to rolls 120 and 124 through vacuum voids (not shown). Alternatively, different web control methods could be used depending on the type of cutting the plasma unit is intended to provide according to the instant process need, such as slitting (e.g., FIG. 6), cross-cutting, profile cutting (e.g., FIG. 8), side-web notch removal (such as a leg cutout of a running web shown in FIG. 11) or cookie-cutting of individual shapes out of the running web (FIG. 12). Alternative to vacuum rolls, a draw roll process could be used, in which web tension is maintained as web is drawn through the rolls 120 and 124.
[0046] Referring now to FIG. 10, an alternate embodiment of a pair of smooth profile electric die rolls 126 is shown with a generated plasma pattern 26 generated between electrically conductive surfaces 130 on them acting upon a web of material, shown in closeup in FIG. 10A. In this embodiment smooth profile electric die rolls 126 can be formed of two different materials. A first electrically conductive material 130 can be placed into a desired pattern within an electrically non-conductive material 128 (e.g., ceramic). To drive the web 10 in this effective virtual edge profile embodiment, a pattern or profiled shape of electrically conductive material (metallic) could be combined with a non-conductive material (e.g., ceramic) and in this case the web 10 could be wrapped around the roll for control, eliminating the need for an opposing roll. In an alternative embodiment, a single smooth profile electric die roll 126 could be used, with a stationary opposing electrical contact placed in proximity to electrically conductive material 130 to achieve the plasma pattern 26 acting upon web 10 as desired.
[0047] Referring now to FIG. 11, an alternate embodiment of a pair of smooth profile electric die rolls 132 with a generated plasma pattern 26 generated between patterns 130 of electrically conductive material 130 acting upon a web of material is shown. The illustrated embodiment shows the smooth profile electric die 132 rolls executing a side cutout pattern.
[0048] Referring now to FIG. 12, an alternate embodiment of a pair of smooth profile electric die rolls 134 with a generated plasma pattern 26 generated between cookie cutter patterns 130 acting upon a web of material 10 is shown. Because this embodiment will create scrap pieces, referring now to FIG. 13, a side view of a vacuum assisted scrap material recovery system for recovering a cutout 10a of web 10 is shown. A scrap piece 10 is drawn down into the roll 130 through a surface void 136 in the roll, with vacuum from source 140 withdrawing the scrap pieces 10a into a waste-stream through a hollow shaft 138 of the roll. Alternatively, surface methods such as a ripper roll (See U.S. Pat. No. 8,293,056 incorporated herein by reference) or surface suction nozzles positioned over the scrap regions 136 could be used. In FIG. 13, hollow shaft 138 can be stationary or driven, while roll 134 is driven independently or jointly.
[0049] The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
