|Publication number||US3867935 A|
|Publication date||Feb 25, 1975|
|Filing date||May 14, 1973|
|Priority date||May 14, 1973|
|Also published as||CA997918A1, DE2422975A1, DE2422975C2|
|Publication number||US 3867935 A, US 3867935A, US-A-3867935, US3867935 A, US3867935A|
|Inventors||Norman R Eisdorfer, John M Lesniak, Bernard M Lichstein|
|Original Assignee||Johnson & Johnson|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (2), Referenced by (34), Classifications (17)|
|External Links: USPTO, USPTO Assignment, Espacenet|
[ Feb. 25, 1975 United States Patent [191 Eisdorfer et a1.
3,683,921 8/1972 Brooks et 128/156 PLIED ABSORBENT STRUCTURES  Inventors: Norman R. Eisdorfer, East Brunswick; John M. Lesnialt, gnglishtown; Bernard Lichstein, Primary Examiner-lune l-l. Laudenslager Elizabeth 1 of Attorney, Agent, or Firm-Jason Lipow  Assignee: Johnson & Johnson, New
May 14, 1973  Filed:
ABSTRACT  Appl. No.: 359,802
A surgical dressing is provided comprising a plurality of plies of a textile-like nonwoven fabric of unbonded, mechanically entangled fibers. The dressing exhibits MA U 8L U rm 1.] 2.1 55 11 an absorption capacity per gram of total fabric at least equal to the absorption capacity per gram of a single ply of said fabric and additionally, exhibits an unusually low propensity to lint.
 Field of Search... 128/156, 155, 132 R, 290 R,
References Cited UNITED STATES PATENTS 2,897,108 Harwood 128/296 X 8 Claims, 5 Drawing Figures PLIED ABSORBENT STRUCTURES BACKGROUND OF THE INVENTION This invention concerns absorbent structures such as dressings, bandages, catamenial sanitary napkins, tampons, incontinence pads, and underpads and, in particular, is directed toward absorbent dressings such as those used in surgical procedures.
Absorbent dressings are used in an operating theatre to serve a variety of functions such as, for example, to staunch the flow of blood, to apply medication, to wall off organs and to separate and dry tissue. It is basic that the dressing used for all such purposes be capable of absorbing fluids and maintaining its structural integrity. Unfortunately, these criteria are, to some extent, in conflict as those materials which are highly absorbent tend to have little structural stability. For example, cotton wadding, wood pulp and the like, while highly absorbent do not, in themselves, maintain their structural integrity and consequently, the art has found it necessary to compromise by using a loosely woven material, cotton gauze commonly being the material of choice.
Several drawbacks reside in the use of cotton gauze. Firstly, a single or double layer of gauze exhibits relatively little absorbency and so surgical gauze dressings have required many layers of gauze, e.g., 16, in order to obtain the requisite absorbent capacity. This has proven to be an uneconomical method of providing extra absorbent capacity as it has been discovered that, while the total absorbent capacity increases with each increasing layer of gauze, the absorbent capacity per unit weight of dressing decreases. Said in other words, the additional layers add less and less to the increase in absorption capacity. Further, gauze dressings have been found to be unsatisfactory for many applications because of their tendency to deposit undesirable quantities of lint. Lint, as used herein, is particulate matter which tends to separate from the dressing during use. When left in a wound, lint may cause inflammation, adhesions and the formation of granulomata. The dangers of lint are more acute in the'so called full thickness incisions as are encountered in suchsur gical procedures as tracheotomies and cardiovascular procedures wherein lint can form the focal point for the growth of thrombi which in turn may result in the formation of emboli, and laparotomies and thoracotomies resulting in turn in the formation of adhesions and possibly granulomata.
Because of the drawbacks of gauze, the art has long been devoted toward finding suitable substitutes. For example, in US. Pat. No. 3,081,515 issued to H. W. Griswold .et al on Mar. 19, 1963, a foraminous nonwoven fabric is described as a substitute for gauze in surgical dressings. Such as fabric, in the unbonded state (i.e., with no additional adhesive binder material added) has been found to be highly absorbent. I-Iow hence, this method of producingdressings does not cure the drawbacks associated with cotton gauze.
Accordingly, there has heretofore been no dressing available which can overcome the drawbacks of inefficient absorbency and undesirable linting associated with th prior gauze dressings while maintaining its structural integrity under stress.
SUMMARY OF THE INVENTION It has now been discovered that an absorbent dressing can be provided which overcomes the drawbacks heretofore associated with cotton gauze dressings. This dressing is made up of a plurality of plies of a textile like nonwoven fabric of unbonded, mechanically entangled fibers randomly entangled with each other in a pattern of localized entangled regions interconnected by fibers extending between adjacent entangled regions. This fabric and a method for making the same is described in US. Pat. No. 3,485,706 which issued on Dec. 23, 1969 to Franklin Jones Evans. It has been discovered that an absorbent dressing comprised of a plu rality of plies of such nonwoven fabric, when said fabric is selectively chosen to have a Tensile Energy Absorption value of at least 1.0 foot pounds per square foot in both the machine and cross direction, cures the drawbacks heretofore experienced in prior absorbent dressingsnspecifically, it has been discovered that, for some reason as yet unknown, the dressings of this invention exhibit an absorbent capacity per gram of total fabric in the dressing at least equal to the absorbent capacity per gram of a single ply of the fabric. In fact, when more than two plies of the fabric are used, the dressing actually exhibits an increase in the absorbent capacity per gram as contrasted with a single ply value. This property is entirely unexpected in view of the fact that the commonly used gauze dressings exhibit essentially the opposite characteristic. Further. when a fabric such as that described in the aforementioned patent to Evans is chosen so as to have a Tensile Energy Absorption value of. at least 1.0 foot pounds per square foot, the absorbent dressing maintains its structural integrity to an extent at least comparable to that of gauze dressings and exhibits a marked reduction in the degree oflinting. Linting of no more than 0.008 mg. of particulate matter per in. of exposed area is obtained in contrast with thatof cotton gauze which typically is about twice as high. This marked reduction in linting is ofparticular importance in absorbent dressings such as laparotomy pads used in critical surgical procedures. In a specific embodiment, a single use laparotomy pad is provided comprising a plurality of layers of the textilelike nonwoven fabric of this invention having interlayers of a meltable polymeric scrim placed therebetween to provide the wet resiliency requisite in large laparotomy pads and to. provide means for bonding the plurality of layers together by fusing the polymeric scrim.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet of the prescribed fabric of this invention prior to folding into an embodiment of a dressing of this invention,
FIG. 2 is a perspective view of a dressing of this invention;
FIG. 3 is a perspective, partially fragmented view of a second embodiment of a dressing of this invention;
FIG. 4 is a perspective view of a laparotomy pad utilizing the construction shown in FIG. 3; and
FIG. 5 is a graphical representation illustrating the advantageous absorptive properties of the dressings of this invention.
DETAILED DESCRIPTION OF THE INVENTION The unique surgical dressings of the invention incorporate nonwoven textile fabrics made in accordance with the teachings of US. Pat. No. 3,485,706, issued to F. J. Evans on Dec. 23, 1969. As described therein, these fabrics (hereinafter referred to as, "mechanically entangled fabric) comprise fibers locked into place by fiber interaction to provide a strong cohesive structure which maintains its structural integrity without the need for adhesive binders or filament fusing. The fabrics have a pattern of entangled fiber regions of higher area density (weight per unit area) than the average area density of the fabrics as a whole and there are interconnecting fibers which extend between the dense entangled regions and are randomly entangled with each other in the dense entangled regions. As is described in the aforementioned patent to Evans, the entanglement is accomplished by first preparing a loose layer of fibers and then treating the layer with liquid, jetted at a pressure of at least 200 p.s.i.g., from a row of small orifices, to convert the layer directly into the nonwoven fabrics useful in the surgical dressings of this invention.
In accordance with this present invention, it has been discovered that by incorporating certain of the mechanically entangled fabric of Evans into a multiplied sponge dressing, many of the drawbacks heretofore associated with prior gauze dressings are obviated. This type of fibers used in the dressings of this invention must generally be wettable fibers or fibers which have been treated so as to be wettable. In some cases, blends of wettable fibers in combination with small quantities of non-wettable fibers may be used. Fibers of cotton, rayon, polyethylene terep'hthalate, polyamides, cellulose acetates, polyacrylonitriles, acrylonitrile-vinyl chloride copolymers, reconstituted protein, polyolefins and blends of these are all useable fibrous systems. Included in this group are hydrophobic fibers which have been treated to give them hydrophilic characteristics. Examples of such treatment are the grafting of polymeric substances onto the fiber surfaces by means of forms of radiation, free radical initiators and other polymerization techniques known in the art. Still other examples of such treatment are the use of wetting agents, rewetting agents and modification in the surface by chemical reaction such as the mercerization of cotton and the caustic treatment of polyethylene terephthalate. In this connection, it is, of course, important to avoid the use of such modification techniques as will be incompatible with the final use of the fibers in a surgical procedure, such as the use of methods leaving residual chemicals which may leach out of the dressing and into body wounds.
The fibers should have a staple length and denier compatible with attaining the strength and decreased particulate matter deposition described herein. Generally, the denier may vary from about 0.5 to about 3.0 with a range of about 1.0 to about 2.0 being preferable. Fiber staple lengths may vary from about 0.25 to about 1.5 inches with lengths of about 0.5 to about 1.25 inches being preferable. The fabric weight per unit area may vary from about 0.5 to about 3.0 ounces per square yard depending upon the degree of bulk desired in the ultimate product. Preferably, the weight per unit area should be about 0.75 to about 2.0 ounces per square yard.
It is desirable, in many dressing applications, that the fabric be apertured. Apertures can provide the dressing with desirable added bulk without the necessity for providing additional fibers. An apertured fabric is less slick, wads less when wet and is more useful in a surgical procedure such as the separation of tissue where a somewhat abrasive character is required for the dressing. From an aesthetic point of view, apertured fabrics more closely resemble the familiar gauze dressings. The apertures may be formed in the fabric by methods now well-known in the art such as, for example, by needle punching or by a jet of fluid impinging on the fabric which is supported on a patterned substrate. The degree of open area of the aperture will vary in accordance with the desired final use of the product, a degree of openness of about 50 to 500 holes per square inch being generally suitable, with an open area of about to 400 holes per square inch being preferred.
In order to be useful as a surgical dressing, the fabrics must have a degree of mechanical entanglement sufficient to have the resulting product maintain its structural integrity under the conditions of use. Specifically. it has been found that the fabric should have a Tensile Energy Absorption value, in both the machine and cross direction, of at least about 1.0 ft.-lbs./ft. and preferably at least about 2.0 ft.-lbs./ft. The Tensile Energy Absorption value is defined as the area under a stress strain curve which is developed by placing the fabric under tensile stress in accordance with the method described in test T494 SU-64 suggested by the Technical Association of the Pulp and Paper Instute (TAPPI) in 1964.
It is important in this instant invention that the above defined minimum tensile strength be accomplished essentially by a sufficient degree of mechanical entanglement rather than by the use of adhesive binders. Thes binders, generallyeither a latex applied in the form of an emulsion to a weak web of fibers or a crosslinked resin system, are undesirable from the point of view that they tend to interfere with the absorptive properties of the resulting dressing. While the reason for this is not entirely understood, it is possible that the presence of the binder interferes with the communication between the capillary-like spaces of the fibrous fabric, this communication believed to be essential for a good absorbent material. Still another possibility is that the binders commonly used are less hydrophilic than the fibers, result in an overall loss of absorptive characteristics. Perhaps a still more important reason for using the essentially binderless dressings of this invention is that, since these dressings are to be used in connection with body wounds, the essential absence of binder obviates the possibility of introducing substances into the body, either by leeching out or by primary contact, which may induce or cause adverse tissue reactions as, for example, toxic or allergenic responses.
The mechanically entangled fabric has, in accordance with this invention, been incorporated into a surgical sponge, using a plurality of plies. Referring to FIG. 1, illustrated therein, is a single rectangular sheet 10 of the prescribed mechanically entangled fabric which may be folded to produce a multiplied surgical sponge such as the eight-ply sponge 12 shown in FIG. 2. The sheet 10 is first folded along line A-A and then along line 8-8 so that lines C-C and C-C' coincide. The final product, sponge 12, is achieved by folding once more about coinciding lines C-C and C'-C'. Attached to sheet is an X-ray detectable element 13 such as, for example, a filament of a polyolefin which has, embedded therein, barium sulfate or other suitable X-ray opaque material. As shown in FIG. 1, the element 13 is preferably located near line A-A so as to be centrally positioned in the final product.
FIGS. 3 and 4 illustrate still another embodiment of this invention wherein the prescribed mechanically entangled fabric is incorporated into a laparotomy pad 14. These pads generally are used within body cavities during major surgical procedures and, in addition to providing absorbency, must also perform the function of walling off organs and covering the outer edges of an incision. Accordingly, the laparotomy pads require a degree of wet resiliency in order to maintain their bulk characteristics when performing these non-absorption functions. The embodiments of this invention shown in FIG. 3 incorporates thin thermoplastic grids l6 and 17 interlayered between plies l8, l9 and of the prescribed mechanically entangled fabric. A preferred grid material may be, for example, made of polyolefin such as, for example, polypropylene which may weigh between about 20 to about 70 grains per square yard. The degree of openness of the grid must be sufficient to preclude interference with the absorbing characteristics and flexibility of the pad. Hole patterns such as 3 X 5, 5 X 5, 9 X 9 or 12 X 12 holes/inch are preferred. The entire laminate of fabric plies interlayered with thermoplastic grids may be bound together, as shown best in FIG. 4. by heat sealing, at least at the marginal portions 18 of the pad 14 so as to fuse the grids 16 and 17 and form an integral bond with the fabric plies. To assure still greater integrity of the structure of the laminate, additional heat sealing points 20 are provided inward of the margins 18, these shown to be in a cross-like pattern in FIG. 4. It will be understood by one skilled in the art that other patterns and arrangements of heat sealing points may also be used. It will also be understood by one skilled in the art that the plies of the pad may be bound together by means other than heat sealing, such as ultrasonic sealing or by sewing. The laparotomy pad 14 is provided with a handle 22 which may likewise be heat-sealed to the pad or alternatively, may be sewn on. As in the prior embodiment, the laparotomy sponge may be provided with X-ray detectable elements 24 and 26.
The dressings of this invention exhibit properties which are totally unexpected when contrasted with prior multiplied dressings. Specifically, it has been discovered that both the absorbency characteristics and the degree of linting of the multiplied structure is surprisingly improved.
With respect to the absorbency characteristics, it has been found that, as the number of plies are increased beyond a single ply, there is no loss in the average total absorbent capacity for liquid per unit weight of dressing. In fact, by increasing the number of plies beyond two, there is actually an increase in the absorbent capacity" per gram. This result is particularly surprising when contrasted to the commonly used cotton gauze dressings which exhibit just the opposite result, i.e., the average total absorbent capacity for liquid per unit weight of gauze dressing decreases with increasing number of plies. The extent of such decreases in the absorbent capacity of prior art gauze dressings is considerable and, for example, may be as high a decrease as ten percent of the single-ply value and in extreme cases, as high as 25 percent of the single-ply value. In 5 contrast to this, no such decrease in absorbent capacity is noted with the dressings of this invention. In fact, an increase is noted of approximately at least about 3 percent for a five-ply sponge and still greater increases for a ten-ply dressing. This is advantageous in that less material may be used to obtain the requisite absorption capacity. Concomitant with this advantage, is the fact that the use of less material or, stated in other words, fewer plies of fabric, means that less surface of the fabric is incorporated into each sponge. Since the degree of linting, i.e., deposition of particulate matter is to a major extent a function of the area of the material used, the fact that less area need be used, coupled with the other herein prescribed requisites of the dressing, results in a substantial reduction in the degree of linting. Thus, for example, a sponge made in accordance with the teachings of this invention will exhibit a degree linting of less than about 0.008 mg of particulate matter per in. of exposed area when used in a multiplied structure. In contrast therewith, a cotton gauze sponge will exhibit a degree of linting of about 0.0 I 2 mg of particulate matter per in. of exposed area. This comparison has been made after the usual precautions have been taken with respect to limiting the linting of gauze dressings. Specifically, because of the nature of cut gauze, a great deal of particulate matter is released from the cut edges and so these are generally inwardly folded and buried within the folded dressing. Further, the actual cutting of the gauze before folding must be accomplished by the specialized technique of crush cutting wherein the-cut ends of the gauze yarns are sealed by crushing into an elliptical crimped configuration to prevent loose fibers from working themselves free. While all of these precautions are taken with respect to gauze dressings tested, none are necessary for the mechanically entangled fabric dressings of this invention. Had such precaution not been taken withthe gauze dressings, the contrast in degree of linting would be markedly greater.
To further illustrate the advantages of this invention, the following examples are given:
EXAM PLE l Samples of dressings having varying number of plies are prepared from three types of fabrics. The first type consists of surgical grade, bleached and scoured cotton gauze (U.S. Pharmacopoeia Type VII) having a thread count of.20 warp threads by l2'fill threads and weighing 0.6 ounces per square yard. The second type consists of surgical grade,.bleachedl and scoured cotton gauze (U.S. Pharmacopoeia Type lll) having a thread count of 28 warp threads by 24 fill threads and weighing 1.0 ounces per square yard. The third type, in accordance with the teachings of this instant invention, consists of mechanically entangled fabric madefrom percent surgical grade rayon fibers, the fibersbeing of 1.5 denier and having a staple length of ii-inch. The mechanically entangled fabric weighs 1.0 ounces per square yard and. is apertured to an open area of about 300 holes per square inch.
The samples are prepared in disk form having a diameter of 68.5 millimeters. The samples are tested to determine their total absorbent capacity with distilled are provided to insure that the hydraulic head of the liquid in the aperture at a level essentially equal to the Eight samples of various types of surgical sponges are top surface of the smooth plate is essentially zero prepared. The first and second types are conventional throughout the test period. The means for insuring this cotton gauze sponges consisting of, respectively, the 20 hydraulics head relationship are illustrated in the de- X 12 count and the 28 X 24 count gauze described in scription of a constant flow burette as given in the Jourthe prior example. The remaining types are made in ac- Ilal of Chemical Education, Volume 47 at P g cordance with this invention and comprise mechani- December 1970- Each of the mple was cally entangled fibers of the various kinds reported in placed on the top surface of the plate above the aper- Table II below and having various weights per unit area ture and allowed to absorb liquid and reduce the level as likewise reported in Table ll. Eight samples of each in the liquid reservoir until no further level change was 15 t p ar tested for particulate matter released by dipnoted in the reservoir. The volume of liquid absorbed i the sample into 1,000 ml of distilled water cony each sample was notedtained in a beaker. The sample, held at its edge by cru- Table I below, summarizes the results of these tests ibl tongs i di d, t submersion, into the water and indicating the number of Plh?S used for each p withdrawn five times. Each time the sample is dipped, the yp of absorbent used in each p and the it is agitated back and forth five times. The solution is sol'beht p y of each Sample, which is expressed in then filtered into a vacuum flask through a crucible terms of the total p y of each plied Sample as 3 having a porous fritted glass bottom and first having Percentage of the Single p y Capacity in Cubic centimebeen rinsed with distilled water, dried in an oven at ters of liquid absorbed h gram of dresshlg- 105C. for 3 hours and then cooled in a desiccator for V H 1 hour. The weight of the cooled and dried crucible has been recorded. The filtered solution is returned to the TABLE I beaker and the above-described dipping, agitating. I withdrawing and filtering procedure is repeated for of Plies fgg g g gjg 235g? each of the remaining samples of the same dressing type. The crucible is then dried to constant weight in o 20 X 12 28 x 24 ghs h f fi an oven at C. and weighed once again the differ- Gauze Gauze Fabric ence in weighing being recorded. This difference in weight is divided by the total exposed surface of all g :88 :88 :88 sponge samples and is reported in Table ll as the weight 4 89.5 100 103 of particulate matter released per unit exposed area of t; 73.6 91.5 sponge. 9 l06 As Table ll indicates, all of the mechanically entang2 gig gled sponges of this invention exhibit a markedly decreased deposition of particulate matter as compared to conventional gauze sponges. Typically, the particu- FIG. '5 is a graphical representation of these data late matter deposition is reduced by a factor greater h i th b i i th number of pli d th than two. It should be further noted that the nature of dinate is the total absorption capacity per gram as a the particulate matter deposited from the gauze sponge percentage of the single ply capacity per gram. The differs from that ofthe mechanically entangled sponges data points for the 20 X 12 gauze samples, the 28 X 24 of this invention. It is observed that lint from the gauze gauze samples and mechanically entangled samples are sponges consists essentially of pieces of yarn about plotted as Xs, triangles, and circles, respectively. As is 0.l30.32 mm in diameter, most of which are about 1 evident from FIG. 5 and Table I, both gauze samples mm in length although pieces as long as about 6 and 7 characteristically exhibit a decreasing total absorbency mm are not uncommon. intermingled with these pieces per gram as the number of plies are increased, this of yarn are loose, short fibers which are components of trend being most noticeable beyond four plies. In said yarns and such impurities as bits of cotton husk, marked contrast therewith, the novel mechanically enleaf and stem. In contrast with this, the mechanically tangled samples of this invention exhibits exactly the entangled sponges deposit lint particles which are subreverse relationship whereby the absorbency per gram stantiall malle being of dust-like quality.
TABLE I] Weight Particulate Matter Sponge Type Fibers (oz/yd?) (mg/in?) Gauze Cotton yarn, 20 X 12 0.6 0.0134 Gauze Cotton yarn. 28 X 24 1.0 0.01 12 Mechanically Entangled 100% Rayon 1.0 0.0049 Mechanically Entangled 100% Rayon 20 0.0055 Mechanically Entangled Rayon, 25% PET" l.l 0.0057 Mechanically Entangled 75% Rayon. 25% PET l.l 0.0060 Mechanically Entangled 10% Rayon, PET" 1.0 0.0040 10% Rayon, 90% PET 1.0 0.0044
Mechanically Entangled increases with the number of plies, the increase being noticeable beyond two piles and still more evident at four plies.
EXAMPLE ll Polyethylene terephthalate Polyethylene terephthalate grafted with polyacrylic acid EXAMPLE 111 This example illustrates the advantages of the instant invention over prior art attempts to produce nonwoven surgical sponges. Two samples of single-ply fabrics are made in accordance with the method described in US. Pat. No. 3,081,515, issued to I-l.W. Griswold et al on Mar. 19, 1963, using 100 percent rayon fibers having a denier of 1.5 and a staple length of %in. The first sample is made from a carded web and is provided in the unbonded state. The second sample is likewise made from a single-ply carded web and is then impregnated with a crosslinkable acrylic emulsion polymer, the quantity of polymer used being equal to about 30 percent of the weight of the unbonded web. Both samples are tested for absorbent capacity as described in Example 1. Both samples are also tested for their Tensile Energy Absorption values using the method described by the Technical Association of the Pulp and Paper Industries (TAPPI), Suggested Method T494 SU-64, 1964. Samples of single ply mechanically entangled fabric prescribed by this invention and identical to that of Example 1 are similarly tested and the results are reported in Table [11 below.
TABLE III It will be apparent to one skilled in the art that many modifications to the invention are possible without departing from the scope and spirit thereof.
What is claimed is:
l. A surgical dressing comprising a plurality of plies of a textile-like nonwoven fabric of essentially unbonded, mechanically entangled fibers randomly en- 10 tangled with each other in a pattern of localized entangled regions interconnected by fibers extending between adjacent entangled regions, said fabric having a Tensile Energy Absorption value: of at least 1.0 foot pounds per foot square, in both the machine and cross directions and saiddressing having an absorption capacity per gram of total fabric at least equal to the absorption capacity per gram ofa single ply of said fabric.
2. The surgical dressing of claim 1 having a degree of linting of lessjhanqpqfl rng. of particulate natter pen inch square of exposed area.
3. The surgical dressing of claim 1 wherein each ply has a weight ranging from about 0.75 ounces per yard square to ab0ut 3.0 ounces per yard square.
Wei ht Absorption Capacity T E A Sample (oz./y (cc/gm) ft.-lb./ft.
Machine Cross Direction Direction Carded, Unbonded 1.0 8.5 0.21 0.01 Carded, Bonded 1.1 5.6 5.36 4.35 Mechanically Entangled L0 8.3 4.54 2.88
' Tensile Energy Absorption value weetes b r.
As is shown in the above table, the bonded samples exhibit good absorbency but are insufficiently tensilestre ss resistant to suffice as a material of construction for a surgical sponge. In fact, this material is so weak that when attempts were made to determine the particulate matter deposited by a sponge made from such a fabric, in accordance with the method described in the foregoing example, the sponge lost its structural integrity. As is suggested by Griswold, the unbonded materials were strengthened by impregnating them with a binder. In this form, the samples tested showed ade quate tensile stress resistance. However, as is clearly shown in the above table, the absorptive capacity is greatly diminished. In comparison with both of the aforementioned samples, the materialprescribed by g the teachings of this invention exhibited both satisfacqry. tren th. and. satis aqt yVabsq p qasapefittw 4. The surgical dressing of claim 1 wherein the Tensile Energy Absorption value is at least about 2.0 ft.-
40 lbs/ft. in both the machine and cross directions.
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|WO2003059232A2 *||Jan 15, 2003||Jul 24, 2003||Kimberly Clark Co||Absorbent article with reinforced absorbent structure|
|WO2005016205A1 *||Mar 4, 2004||Feb 24, 2005||Karen Hargett Bean||Absorbent article having a stretchable reinforcement member|
|U.S. Classification||604/385.201, 604/366, 602/45, 604/370|
|International Classification||A61F13/00, A61F13/49, A61F13/53, A61F13/472, A61F13/15|
|Cooperative Classification||A61F2013/00604, A61F13/44, A61F2013/00744, A61F13/00042, A61F13/00034|
|European Classification||A61F13/44, A61F13/00A6D, A61F13/00A6|