US2734505A

US2734505A - Coated tampon

Info

Publication number: US2734505A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

Feb. 14, 1956 F. P. PARISH COATED TAMPON Filed May 7, 1954 Alli v INVENToR.

F/r/V/f P. /DA /Q/S United States Patent O COATED TAMPON Frank P. Parish, Taneytown, Md., assignor to Sanitary Products Corporation, Chicago, Ill., a corporation of Illinois Application May 7, 1954, Serial No. 428,263

. 8 Claims. (Cl. 12S-285) The present invention relates to tampons and, more particularly, to an improved catamenial tampon, and to an improved method of manufacturing the same.

U. S. Patents Nos. 2,340,311 and 2,440,141 to Arthur B. Donovan are examples of the type of tampon with which this invention is particularly concerned. The tampon has a relatively large mass of absorbent material that is compressed into a relatively small volume of cylindrical form. While still under compression, the cylinder is heated to produce an ironing effect, after which the entrant end is rounded off and dipped into a solution of. a lubricant coating composition. The coating is then dried to provide a binding or retentive film which retains the underlying compressed absorbent material in the compressed state. The composition of the coating is such that it dissolves readily in the body uids and allows the compressed material to expand to facilitate the absorption of a relatively large volume of the fluids. A surface-active agent dispersed in the lilm acts on the body fluid to lower its surface tension so that it penetrates rapidly into the film or coating and thus increases the rate of dispersion of the film into the body uids. At the same time, the lowering of viscosity and surface tension facilitates absorption of the fluids by the material of the tampon.

y It has been found that the formation of a lubricated tip on a compressed cotton tampon is an operation that may be facilitated provided that the end of the tampon is first coated with a primary coat so that the cotton will notabsorb the fluid which is used to form the tip. This fluid must of necessity be water soluble or water dispersible and will be absorbed by the cotton, whichy then has a tendency to form a rough tip. It is possible to apply the fluid in two steps, drying between each step, but the drying operation requires time and machinery and is not as practical as the present method. To overcome these disadvantages it has been found preferable and it is desirable to apply a substance to the cotton which prevents the fluid forming the tip from being absorbed by the cotton and tending to form the' end making it rough and irregular. The primary coat that is applied is preferably water soluble of water dispersible. It can, however, consist of a water-insoluble material formed in a smooth layer over the end and of such a thickness that as the cotton swells from absorption of the menstrual luid and the outer portion of the tip dissolves, this primary coat will crack and break apart readily and not cling to the tampon so as to prevent absorption and hinder the opening ofthe end of the tampon.

It has been found that the primary coat, even if water soluble or water dispersible, should not bind the end fibers of the cotton tampon so tightly that a long time is required to expand the tampon. It should, however, serve to lightly bind the end so that it can be shaped giving a smooth, rounded end for applying the fluid used to form the tip which is disclosed in the Donovan patents.

It is also necessary that the primary coat be of such a consistency that it can be readily applied, preferably ice in paste form, and then cooled to form a solid film at the time of application to the tampon. ln certain circumstances, it has been found that the primary coat may be constituted of a powder or a waxy solid. It is preferred to apply the powder as a powder by a spinning cup in contact with the end of the tampon and the waxy solid as a liquid just above its melting point, and then cooling to form a solid film over the end of the tampon at the time of application to the tampon. The waxy solid can also be applied as an emulsion which breaks when applied to .the tampon and deposits a waxy film. on the end of the tampon.

The preferred method is to apply a paste which is of such a consistency when cool that it can he forced through a small opening in a die as a continuous ribbon in metered amounts and will cling to the vend of the tampon. The paste is then distributed over the end of the tampon by a spinning cup which shapes and` coats the tampon ends partially up the sides with the paste. The paste should be in a liquid or a semi-liquid form when hot so that the tubes used to feed the metering pump can be filled completely without the presence of entrapped air, which would be the case if a paste or solid were used. This hot liquid then sets to a paste form when cool giving a tube completely filled. y

It is also preferred that the Vpaste be such that it will dry quickly to a solid or semi-solid sortnat it will' not penetrate the end and thus bind the cotton fibers preventing the end from expanding when ythe tampon is'used.l

Furthermore, if the paste does not dry quickly, the fluid used for tipping will also penetrate and bind the end, forming a rough tip. The dying of the primary coat can be accomplished with a blast of air either hot or cold, althoughrit is preferred to have a substance incorporated in the paste that will volatilize rapidly at room temperature, leaving a coat that resists or retards the penetration of the subsequently applied tipping fluid. The same result can be accomplished by making pastes that have` a small proportion of liquid. v

It is an object of this inventionto provide a tampon possessing increased advantages over known coated tampons and having means preventing absorption of the coating prior to its dissolution following insertion in a body cavity.

Another object is to provide a self-sustaining tampon of compressed absorbent material having on its entrant end portion a shape retaining and confining layer of a paste capable of retarding absorption by t'ne tampon body of a subsequently applied liquid coating, for an interval of time suicient for the subsequent coating to dry.

A further object is to provide a self-sustaining tampon of compressed absorbent material provided on its entrant end with a covering layer of a water-dispersible surfaceactive agent capable of lowering the surface tension and viscosity of menstrual fluid, and which, following its application, is non-aqueous at any stage prior to dispersion 1n use.

Other objects will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a perspective View of an embodiment of my invention, and

Figure 2 is an axial section through the entrant end portion of a tampon comprising a further embodiment of the invention. Y

As illustrated in the drawing, the tampon comprises a cylindrical body 3 of tightly .compressed fibrous absorbent material, preferably absorbent cotton, that has been heat treated over itsl surface to produce an ironing effect whereby the surface fibers are pressed into a smooth, relatively stil skin. This ironing process imparts suftcient rigidity to the body to make it self-sustaining. The cylindrical body is formed with a rounded entrant end and, at its opposite end, is provided with a pull string 4 for removal.

The entrant end portion of the tampon has applied thereover a covering layer of water-soluble or waterdispersible material that is moisture retardant; that is, retardant to the passage therethrough of liquid or moisture externally applied.` The material may, if desired, be impervious, but preferably is water soluble and water dispersible. When applied, the material restrains the subjacent absorbent body of the tampon against loosening and expansion from its compressed state, and retains the entrant end in rounded shape.

In the embodiment of the invention shown in Figure 2, the layer 5 constitutes a supporting base for a subsequently applied coating 6. The exterior coating 6 may have any desired characteristics. It is preferred, however, that it be a composition falling within the scope of the compositions `disclosed in the illustrative examples given hereinafter. In such case, the covering 5 is comprised of material that is capable of retarding the passage therethrough of liquid or moisture from the solution of the outer coating, at least long enough to permit the outer coating to be dried. Although it is preferred that the inner covering layer 5 be water dispersible or Water soluble, so that it can readily dissolve in the body fluids, it is within the province of my invention that it be insoluble or practically so. It may have any physical state compatible with its function; for example, a paste, a liquid of high viscosity, a wax, among others. It can be, for example, a paste of toilet soap.

A tampon provided at least on its entrant end with a single covering layer, as shown in Figure 1, in which the layer consists of an initially non-aqueous surfaceactive agent such as a soap paste, particularly a paste of white soap wetted with water, is eminently suitable for use without further treatment or subsequent coating. Any suitable non-aqueous, plastic, cohesive material comprised of a surface tension depressant that is water dispersible or water soluble may be used; preferably it should be capable of ready application at ambient temperatures. Material in paste form is best suited to productionrequirements: it is of low cost, easy to prepare and apply, and is suflciently cohesive to restrain the underlying body of the tampon against loosening. Its plastic nature makes shaping a simple matter and also makes the tampon very easy to insert. It is non-aqueous prior to dispersion, and thus by its nature precludes absorption by the compressed absorbent body of the tampon.

The materials that have been found to be satisfactory in preparing these pastes and to coat the ends of the tampons are pastes made of soap, such as ordinary toilet soap, and water. Y

In the preferred method of application the paste is forced through a small opening so that it is necessary for the paste to be contained in tubes from which it can be forced by a plunger operated by air pressure into a metering pump. To ll the soaper tubes so that there is no air entrapped, the paste is softened by heating until it is a liquid mass and poured into the tubes to cool and set to a paste. If the material used for a primary coat cannot be softened to a consistency such that it will flow into the tubes and fill them without entrapping air, it is difcult to apply the primary coat by this method. If there are air bubbles in the paste, the metering pump will not deliver the same amount of paste for each tampon and the tampon may not be covered enough to keep the tipping uid from penetrating into the cotton.

Although a number of pastes have been prepared from various ingredients as mentioned previously, those made with soap and other ingredients are the most convenient to prepare and are excellent for the intended purpose. Two problems have to be considered in making a paste that is satisfactory. First, the hardness which is measured with a pentrometer. If too hard, it is diicult to force the paste into the metering pump and through its orifice. Also, if too hard, the paste will not properly bind the end of the tampon but will flake ot in the spinning cup giving an insutlicient coating on the end of the tampon. The softening point is related to the hardness so that when a satisfactory hardness is obtained, the softening point is generally high enough to be satisfactory. Both the softening point and the hardness can be varied within wide limits by using different formulations.

Second, is the rate of drying of the paste after it has been applied to the tampon. Formulations in which there is no volatile solvent or a salt have not proven satisfactory using the present method of application. This is because there is no forced drying of the primary coat. Without forced drying the pastes that are not completely satisfactory for the present method penetrate the end of the tampon binding the cotton fibers. together tightly and causing the tip to swell to some extent due to absorption of moisture from the paste. When forced drying is used, this does not occur with these formulations.

ILLUSTRATIVE EXAMPLES OF PRIMARY COAT- ING FORMULATIONS Soap and water solutions Pastes made of' soap and water require a long drying time at room temperature and cause some swelling of the end of the tampon unless dried in a hot air blast. EX cept for this point, these pastes can be applied by the method previoulsy described. These pastes range in composition within the following limits:

Percent Soap 20-45 Water 55-80 Percent Soap 45-75 Water 25-55 Satisfactory results have been obtained by coating a tampon with a paste of the following composition:

Soap About 25%. Water About 75%. Softening point About4l C.

Some examples of soap formulations employed in the present invention are:

EXAMPLE I Percent Limits .85 .93 15.45 to 16.45. 19 3.84 to 4.20. .63 51 .62 H10 14. 30 Maximum glyecrine content 0. 45

EXAMPLE II Percent Limits N530 6.54 Factor 1.97 Hz 13.27 12.67 to 14.30.

The factor included in each type of soap contains numerous builders depending on the particular product.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

I claim:

1. An improved catamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a dried initially liquid iilm containing a water-dispersible, surface active agent capable of lowering the surface tension of menstrual iiuid, and beneath said film a covering layer of material blocking the passage of moisture to the subjacent body of the tampon.

2. An improved catamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a coating of a dried, initially liquid film containing a water-dispersible, surface-active agent capable of lowering the surface tension of menstrual fluid, and a covering layer under said coating, said covering layer comprising material retardant to the passage therethrough of liquid from the ilm for a period of time substantially suicient for the film to dry.

3. An improved catamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a dried initially liquid film containing a water-dispersible agent capable of lowering the surface tension of menstrual fluid, and beneath said lm a coating of material retardant to the passage therethrough of liquid from the film for a period of time substantially sufficent for the lm to dry.

4. An improved catamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a dried initially liquid film containing a water-dispersible, surface-active agent capable of lowering the surface tension of menstrual Huid, and beneath said film a covering layer of a paste retardant to the passage of liquid.

5. An improvedcatamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a dried initially liquid film containing a water-dispersible, surface-active agent capable of lowering the surface tension of menstrual fluid, and beneath said film a covering layer of a paste retardant to the passage of liquid therethrough, said paste comprising soap.

6. An improved catamenial tampon comprising a body of compressed absorbent material having, at least on its entrant end, a dried initially liquid film containing a surface tension depressant for menstrual fluid absorbable in the compressed material of the tampon until dried, and the body of the tampon beneath said film having a covering layer binding the tampon in its compressed state and preventing absorption of matter from said film prior to drying thereof.

7. Method of tipping a catamenial tampon with a solution of material that forms a lubricant film when dried, which comprises, precoating at least the entrant end portion of thetampon with a covering material capable of preventing absorption of the film forming solution into the material of the tampon, applying the solution of film forming material over and upon the covering material, and -drying the applied solution to provide a film tip in situ.

8. In the method of claim 7, said precoat covering material consisting of a water-dispersible paste of soap.

References Cited in the le of this patent UNITED STATES PATENTS 706,778 Pond Aug. 12, 1902 2,092,427 Ross Sept. 7, 1937 2,340,311 Donovan Feb. 1, 1944 2,440,141 Donovan Apr. 20, 1948

Claims

1. AN IMPROVED CATAMENIAL TAMPON COMPRISING A BODY OF COMPRESSED ABSORBENT MATERIAL HAVING, AT LEAST ON ITS ENTRANT END, A DIRED INITIALLY LIQUID FILM CONTAINING A WATER-DISPERSIBLE, SURFACE ACTIVE AGENT CAPABLE OF LOWER ING THE SURFACE TENSION OF MENSTRUAL FLUID, AND BENEATH SAID FILM A COVERING LAYER OF MATERIAL BLOCKING THE PASSAGE OF MOISTURE TO THE SUBJACENT BODY OF THE TAMPON.