US3416525A - Stabilized non-adherent dressing - Google Patents

Description

Dec. 17, 1968 G J. YEREMIAN STABILIZED NON-ADHERENT DRESSING v Filed Dec. 6. 1966 INVENTOR. v GEORGE J. YEREMIAN BY United States Patent O 3,416,525 STABILIZED NON-ADHERENT DRESSING George J. Yeremian, Greenwood, S.C., assignor to Parke, Davis & Company, Detroit, Mich., a corporation of Michigan Filed Dec. 6, 1966, Ser. No. 599,572 3 Claims. (Cl. 128156) This invention relates to surgical dressings and more particularly to a stabilized non-adherent dressing of an improved type.

Prior to the present invention, available dressings have in general failed to provide the intended free, non-adherent release from the healing wound surface. One conventional dressing of the type in question, while not truly non-adherent, nevertheless achieves some improvement with a construction in which the wound is contacted by a smooth perforated plastic film-gauze laminate. One such dressing is shown in US. Patent No. 2,923,298. More recently, a material with superior nonadherent properties has been developed. This superior material, referred to below in detail, is a bonded laminate comprising needled webs of neutral organic plastic resin fiber and cellulosic material. One :face of the laminate is comnosed of porous resin and this serves as the non-adherent contact surface for the wound. One difficulty with this laminated material, however, is that it has -a relatively low abrasion resistance. Also, it tends to delaminate when employed in certain types of dressing, particularly under stress of normal wear. A consequence of abrasion and delamination is that fibrous particles and other small particles can become dislodged from the dressing onto the wound site from which their later removal may be difficult and even distressing.

It is an object of the present invention therefore to provide an improved non-adherent surgical dressing which is stabilized against abrasion, delamination, etc.

It is also an object of the invention to provide an economical non-adherent surgical dressing which can be efficiently made in large volume.

Another object is to provide a surgical dressing which can be safely applied to the wound site and kept there for indefinite periods under widely varying conditions of use without risk of introducing extraneous debris or particles to the wound site.

Still another object is to profide an improped surgical dressing which can readily be manufactured and packaged and thereafter distributed and used under sterile conditions, all the while retaining its intended structural integrity and aesthetic usefulness.

Other objects, advantages, and purposes will be seen in the following description in reference to the accompanying drawings in which:

FIG. 1 is a plan view of a dressing according to the invention showing a non-adherent pad centered on an adhesive coated backing strip; and FIG. 2 is a diagrammatic cross-section of the dressing of FIG. 1 taken on line 2-2.

As seen in FIG. 1 the dressing of the invention comprises a backing strip 19 coated with a suitable pressure sensitive adhesive 11 and supporting a dressing pad 12. The pad and backing can be any of a wide variety of sizes, shapes, thicknesses, etc., for application to various parts of the body, depending on particular requirements. The pad, as is shown and in fact as is conventional, will generally be spaced inwardly from the margins of the backing strip 19, especially to permit sealing of the adhesive u on the skin around the pad edge 14 at all points surrounding the wound site. Although the adhesive surface of the backing is usually sufiicient for maintaining the'pad 12 in position, an optional feature for this purpose is the provision of adhesion zones 13 3,416,525 Patented Dec. 17, 1968 "ice on the underside of the pad indicated by the dotted lines along the longitudinal edges of the pad. The pressure exerted in securing the pad to the backing, in relation to the thickness of the adhesive coating desirably should be such as to tend to embed the edges of the cellulosic layer 16 within the adhesive layer so as to restrain any random loose fibers from lateral movement. The type of adhesive means and backing employed is not critical. Usually these will be selected to simulate the properties of the skin in respect to flexibility, comfort, breathability, etc. If desired, they can be moisture resistant or completely moisture impermeable.

The dressing pad 12 as seen in FIG. 2 extends "from the adhesive coated backing 19 at its edges 14 through the shoulder 15 to the pad face 20. The pad face 20 constitutes the surface intended primarily for direct contact with the wound. The pad is a laminate of two or more layers including a cellulosic layer 16 and a resin fiber layer 17. The cellulosic layer is one having moisture absorption properties and is composed of a nonwoven mat or web of natural fibers such as cotton, artificial fibers such as rayon and mixtures of such fibers; the layers may also contain other fibers or adjuvants such as an inert thermoplastic olefinic bonding fiber, e.g., polypropylene. The resin fiber layer is one permitting free flow to moisture and yet inert and compatible with the wound surface. Any of various resins or mixtures of resins which meet these requirements and which are thermoplastic, as will be hereinafter described, will be satisfactory. The polyolefins such as polyethylene, polypropylene, etc., and other similar inert resin materials are suitable. Polypropylene is preferred for its ability to withstand steam sterilization. Other absorbent layers such as cellulose wadding, open weave textile and the like can if desired be included with the cellulosic layer. The cellulosic layer and the resin fiber layer in the pad according to the invention are secured together by needling and heat fusion. In the needling operation used to produce pads of this type, the somewhat loose laminate is processed through a needling machine wherein the needles are injected through the laminate causing the ensnared resin fibers to pass through the cellulosic layer at random spaced points and the needled fibers 18 are heat fused in place. Fusion of the needled laminate is accomplished conveniently by passing the needled laminate through pressure rolls with the resin fiber layer in direct contact with the heat surface to 'cause the fibers to soften, merge and rearrange to a substantially fiat, smooth integral porous surface with the needled fibers likewise merged into the compressed cellulosic mat. Upon cooling, immediately after leaving the pressure rolls, the resin hardens and the compressed webs are thus transformed into a single integrated laminate having the characteristics of a smooth durable dense blanket structure.

For purposes of illustration, a suitable needled, pressure-secured pad can be made using a sheet of cellulose wadding (14 lbs/ream) laid over non-woven web of rayon fibers (l /s length, 3 denier). A like web of nonwoven polypropylene fibers is laid over the first web (to provide a weight ratio per unit area of 46 parts polypropylene, 21 parts wadding and 33 parts rayon) and the resulting laminate weighing about 4% ounces per square yard is passed through a needling machine having 9 barbs per needle to give between -120 needle perforations per square inch through the laminate. The

laminate is then fed through heat rolls for average exposure of /2 second to 20 pounds per square inch and temperatures above 270 F. suflicient to fuse the resin and provide a smooth surface with non-adherent characteristics.

The laminated pad material which is an improvement over prior non-adherent materials is nevertheless unsatisfactory, as indicated above, because of delamination, low resistance to abrasion, etc. According to the present invention, however, freedom from abrasion damage, delamination and the like is advantageously obtained by the combination of the pad and the adhesive coated backing strip 19 in conjunction with the shoulder 15. The shoulder can be formed in the pad by any convenient forming means such as by pressing between stamping dies or passing the pad edge lengthwise through opposed embossing wheels, the surface contacting the non-adherent side in any case being preferably maintained at elevated temperature sufficient to soften the thermoplastic and thereby impress a permanent set at the edge 14 in the form of a shoulder. Pressure and heat means applied in this Way serve to anchor the resin and cellulosic fibers within the body of the pad and also to render the pad more dense and rigid. Further, loose fibers, whiskers, etc., are desirably eliminated by this procedure, if necessary by first spraying on or otherwise applying a suitable binder such as methyl cellulose solution. The shoulder can extend around the margins of the pad, if desired. In this connection while it is important for the shoulder 15 to extend along and reinforce the major proportion of the edge 14, such a shoulder at the ends of the pad is not essential. The invention contemplates the provision of conventional release strips (not shown) overlying the adhesive layer and pad and a protective envelope suited for sterilizing and maintaining the dressing in sterile condition for ultimate application to the wound site.

I claim:

1. In a surgical dressing having a non-adherent laminated pad with at least one cellulosic layer and a porous resin fiber layer mutually secured by needling means, the improvement comprising an adhesively coated backing strip adhesively secured to the pad surface opposite the non-adherent surface of the pad, the pad being spaced inwardly from the margins of the backing strip with sutficient adhesive surface exposed around the pad to permit adhesive sealing at points surrounding a wound site, and a marginal shoulder constituting areas of increased compression of the pad over at least a major proportion of the pad edge.

2. A surgical dressing according to claim 1 wherein the pad has an oblong shape and is provided with a marginal compression shoulder along the longitudinal edges of the pad.

3. A surgical dressing according to claim 1 wherein the pad comprises a needled non-woven rayon-polypropylene fiber heat bonded laminate.

References Cited UNITED STATES PATENTS 2,923,298 2/1960 Dockstader et al. 128-296 3,122,141 2/1964 C-rowe 128-296 3,156,242 11/1964 Crowe 128-156 3,229,691 1/1966 Crowe 128-156 3,331,728 7/1967 Lane 161-112 ADELE M. EAGER, Primary Examiner.

US. Cl. X.R.

Claims (1)

1. IN A SURGICAL DRESSING HAVING A NON-ADHERENT LAMINATED PAD WITH AT LEAST ONE CELLULOCIS LAYER AND A POROUS RESIN FIBER LAYER MUTUALLY SECURED BY NEEDLING MEANS, THE IMPROVEMENT COMPRISING AN ADHESIVELY COATED BACKING STRIP ADHESIVELY SECURED TO THE PAD SURFACE OPPOSITE THE NON-ADHERENT SURFACE OF THE PAD, THE PAD BEING SPACED INWARDLY FROM THE ARGINS OF THE BACKING STRIP WITH SUFFICIENT ADHESIVE SURFACE EXPOSED AROUND THE PAD TO PERMIT ADHESIVE SEALING AT POINTS SURROUNDING A WOUND SITE, AND A MARGINAL SHOULDER CONSTITUTING AREAS OF INCREASED COM-

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