US 2839059 A
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I JOA 2,839,059 METHOD AND APPARATUS FOR ADHESIVELY CONNECTING THE MARGINS OF A SANITARY NAPKIN WRAPPER ABOUT THE PAD Filed Oct.
June 1 7, 1958 INVENTOR. Cwer 6-. Jon BY V M, My
ArraEmP/S United States Patent METHOD AND APPARATUS FOR ADHESIVELY CONNECTING THE MARGINS OF A SANITARY NAPKIN WRAPPER ABOUT THE PAD Curt G. Joa, Sheboygan Falls, Wis.
Application October 5, 1955, Serial No. 538,587
6 Claims. (Cl. 128-490) This invention relates to a method and apparatus for adhesively connectingthe margins of a sanitary napkin wrapper about the pad.
In the present practice, the margins are generally provided with wide lapping portions of sufficient area so that friction between them will tend, without other connecting means, to maintain the wrapper folded about the pad. Since the gauze used in the wrapper is relatively expensive, this involves considerable waste. In one line of santiary napkins, the margins of the wrapper are stitched together, thereby reducing the amount of lap required.
Various attempts have been made to join the margins adhesively to reduce the required lap. These have not been commercially acceptable because of the expense of the equipment and methods heretofore used and because of the further fact that previously known methods have resulted in so stifiening the wrapper as to make it seem objectionable. According to the present invention, the margins of the gauze wrapper are lapped over the pad in the course of the continuous movement through the machine in which the sanitary napkins are manufactured. Without arresting that movement, a fine spray of quicksetting adhesive is directed externally upon the seam. As distinguished from previous attempts to coat the margins of the wrapper prior to the lapping operation, my invention makes it possible to reduce greatly the amount of adhesive used, the spray carrying through the mesh of the gauze sufficient portions of the adhesive to bring about the required adhesive connection between the wrapper margins without appreciably stiffening the gauze.
No claim is made broadly to the use of adhesive or to the spraying as a means of application of adhesive. On the contrary, the invention is limited to the lapping of the margins of the porous wrapper over the pad and subsequently spraying a time mist of adhesive upon the mesh of the externally lapped margin for penetration of that mesh to connect such margin with the underlying margin.
In the drawings:
Fig. l is a diagrammatic view in perspective showing the practice of the method and indicating the apparatus employed.
Fig. 2 is a diagrammatic plan view of the resulting product.
Fig. 3 is a transverse view taken in cross section on the line 33 of Fig. 2.
Fig. 4 is a greatly enlarged detail view in section.
The general organization of a sanitary napkin machine is disclosed in my Patent No. 2,131,808, dated October 4, 1938. Successive pads 5 are fed at spaced intervals onto a web 6 of wrapping material which usually, but not necessarily, comprises an open mesh cotton gauze.
As the web advances, its margins 7 and 8 are turned into lapping relation over the pads 5, whereby the pads are entubed in the wrapper. In accordance with the present invention, a conventional air brush having a nozzle ice at 9 and supplied with thin adhesive from tank 10 and with compressed air through pipe 11 is used to deliver an extremely fine spray of adhesive directly upon the outer surface of the lapping margin 7 of the wrapper which is disposed over the underlying marginal portion 8 of the wrapper. The finely atomized spray delivered by the air brush is too minute in quantity to stifien the wrapper appreciably. Yet portions of the spray penetrate the mesh or are absorbed in, or adsorbed on, the threads of the wrapper to provide an adhesive connection at 12 between the substantially contacting strands of the lapping marginal portions of the wrapper (Figs. 3 and 4). This is exaggerated for the purposes of illustration in the drawings. In practice, the adhesive is almost undetectable.
The wrapper 6 is ultimately severed as indicated at 13 in Fig. 1, leaving the sanitary napkin complete in readiness for use. Solely for packaging convenience, the wrapper ends 15, 16, which project beyond the entubed pad, are usually folded over onto one of the surfaces of the pad.
While the invention is peculiarly adapted for use in the wrapping of pads to make sanitary napkins, and is conventionally applied to wrappers of gauze, the invention is not limited to these details. Regardless of the article wrapped or the degree of porosity of the wrapper, the invention is applicable both in terms of method and apparatus. It has been used successfully upon non-woven wrapping materials which are entirely or substantially free of visible interstices. As long as the atomized adhesive mist can penetrate the outer lapping margin, the method is elfective.
The product of the method herein disclosed is new in that the pad within the wrapper is virtually free of adhesive and usually has no adhesive connection whatever with the wrapper. Unlike previous attempts to employ adhesive in a sanitary napkin, the present invention leaves the adhesive in the form of fine discrete particles 17 congealed from the individual droplets of the spray and concentrated quite largely in or near the externally lapping margin of the Wrapper. Such droplets as penetrate the outer lapping margin of the wrapper at all are usually completely absorbed in the interlapping margins, the amount of spray employed being too slight to achieve appreciable penetration into contact with the pad. Even the outer margin has virtually no stillness because the mist is so fine that the droplets congeal substantially instantly upon contact, to remain as discrete particles rather than a continuous film.
1. A method of wrapping which comprises lapping the margins of a fabric wrapping material about an article to be wrapped and adhesively joining lapping marginal portions of the wrapping material by spraying a fine mist of adhesive externally upon the strands of the outwardly exposed lapping margin and therethrough into contact with the strands of the underlying margin, the adhesive being absorbed in and adsorbed on said strands as discrete particles whereby to unite said margins by adhesive connection of their contacting strands without substantial stiiiening of the wrapper, no perceptible film of adhesive being formed thereon.
2. The method of sanitary napkin manufacture which comprises wrapping a pad with porous wrapping material comprising fibrous strands and lapping one of the margins of the wrapping material over the other on the upper surface of the pad with strands of said margins in substantial contact and thereafter directing a line mist of atomized adhesive upon the strands of the outwardly exposed lapping margin of the wrapping material and therethrough upon the strands of the underlying margin contacting strands without substantial stiffening of the. wrapping material, no perceptible film of adhesive beingformed on such material. g V
3. The method of sanitary napkins manufacture which comprises the steps. of placing successive pads upon a porous Wrapping web of fabric comprising strands, continuously advancing the web and the pads while folding successive marginal portions of the Web into lapping relation over successive pads with strands of the lapping margins in substantial contact, and developing a finely atomized mist of adhesive and directing such mist upon the strands of the outer margin in' the course of the continuous advance of the web pads for penetration through the outer lapping margin into contact with the substantially contacting strands of the margins of such Web to effect adhesive connection between said margins, the adhesive being so finely atomized and the spraying of a given area of said fabric being so brief that the adhesive forms no perceptible film on the fabric and does not appreciably stiffen the fabric.
4. As a new article of manufacture, a sanitary napkin of the type comprising a pad and a porous wrapper comprising strands and having lapped margins, and an adhesive connection between the lapping margins of the wrapper comprising fine discrete particles of adhesive adsorbed on and absorbed in individual strands and connecting only such strands of said lapped margins as are in substantial contact, the said particles being concentrated adjacent the strands of the outer lapping margin of the wrapper and decreasing in the strands of the inner lapping margin of the wrapper and substantially absent from the pad wrapped therein, the=margius being substantially free of stiffness and free of perceptible, continuous adhesive 'film.
5. The sanitary napkin of claim 4 in which the wrapper comprises gauze and the strands are threads.
6. The sanitary napkin of claim 4 in which thewrapper comprises non-woven material.
References Cited in the file of this patent UNITED STATES PATENTS 1,336,402 Weiss Apr. 6, 1920 2,250,921' Warren July 29, 1941 2,578,664 Bcery et al. Dec. 18, 1951 FOREIGN PATENTS 7 692,890 Great Britain June 17, 1953