US3499448A - Integral tampon shield - Google Patents

Description

March 10, 1970 J. L. JONES INTEGRAL TAMPON SHIELD Filed Feb. 13, 1967 INVENTOR.

United States Patent US. Cl. 128285 4 Claims ABSTRACT OF THE DISCLOSURE This invention teaches a flexible, integrally bonded menstrual shield for a one-piece regenerated cellulose sponge tampon, located in the tampon and adjacent the withdrawal string handle. It includes a teaching of a process for making the menstrual shield, together with a process for simultaneously fabricating a multiplicity of tampons having a menstrual shield.

This application is a continuation-in-part of my 00- pending application on tampons, Ser. No. 350,193, filed Mar. 9, 1964 now US Patent 'No. 3,347,237. My present invention relates to new and useful improvement in menstrual tampons.

This application is also a continuation-in-part of my co-pending application filed as of this application date and titled Tampon Manufacture, which also relates to an improved menstrual tampon structure.

Included in the objects of my invention are:

First, to provide an integral menstrual fluid resistant shield in a one-piece regenerated cellulose sponge menstrual tampon.

Second, to provide an integral leakage preventative shield means for a one-piece cylindrical regenerated cellulose sponge tampon.

Third, to provide an integral compressible menstrual fluid moisture shield for a one-piece radially compressed, minimum pore volume, regenerated cellulose sponge menstrual tampon.

Fourth, to provide a process means to prepare an integral menstrual shield layer to repel leakage of menstrual fluid from the end of the tampon from which the withdrawal string extends.

Fifth, to provide a method of manufacturing integral menstrual fluid resistant shields for a multiplicity of onepiece, regenerated cellulose menstrual tampons.

Further objects and advantages of my invention will become apparent in the following description, to be read in connection with the .accompanying drawings.

FIGURE 1 is a perspective view of a radially compressed menstrual tampon embodying my integral compressible moisture shield.

FIGURE 2 is a perspective view of an expanded or uncompressed menstrual tampon embodying my integral moisture shield invention.

FIGURE 3 is an enlarged cross sectional view through 3-3 of FIGURE 2 illustrating my improvement in a tampon integral moisture shield invention.

FIGURE 4 is a perspective view of a single billet of expanded, fine-pore, regenerated cellulose from which a multiplicity of cylindrical tampons having menstrual shields may be simultaneously cut.

Referring to FIGURE 1, in detail, I show a perspective view of a menstrual tampon 1 having a dry, radially compressed, minimum size pore openings, regenerated cellulose cylinder 2, a withdrawal string 3 coaxially located in and along the cylinder length and extending beyond the cylinder, forming a string handle 4. The

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string handle 4 extends from the compressed cylinder end 5 and does not extend from the cylinder end 6. The compressed cylinder end 5 is the location of the integral flexible, compressible menstrual fluid resistant shield 7.

The integral flexible, compressible menstrual moisture resistant shield 7 of my invention functions to keep the menstrual fluid absorbed by the sponge cylinder 2 from squeezing out of the cylinder end 5, when the cylinder 2 is placed in normal absorption position in a vagina. My invention teaches an integral, flexible menstrual fluid resistant impregnant film former located in a thin cross section area of the sponge tampon end from which the withdrawal string handle extends. The integral menstrual shield 7 is typically inch thick and extends completely over the tampon end 5 area.

In FIGURE 2 I show a polygonal cross section, cylindrical menstrual tampon 10, having a dry, expanded, finepore regenerated cellulose sponge cylinder 11. The cylinder 11 has a regular hexagonal cross section body terminating in the ends 12 and 13. The withdrawal string 14 is coaxially located along the length of the hexagonal cylinder axis and extends from the cylinder end 12 to form a string handle 15. The expanded, integral moisture shield 16 is a menstrual fluid repellant impregnant film former located in a thin, approximately /s inch thick sponge zone at the end 12, and is integrally bonded to and located in the sponge cellular structure of the end 12.

To further illustrate and clarify my invention, FIG- URE 3 represents a cross-sectional view of my invention, typically shown by the view 3-3 through FIG- URE 2. In FIGURE 3, I show the cross-section of cylinder 11 of expanded, fine-pore, regenerated cellulose sponge, having a cylinder end 12, a withdrawal string 14, and a handle 15. The end 12 area is impregnated with a menstrual fluid repellant or fluid resistant film former which forms a menstrual fluid resistant shield 16, integrally bonded to a typically to A3 inch thick cross ielction end 12 of fine pore regenerated cellulose sponge My flexible impregnant and coating or film former renders the sponge end 12 repellant to the penetration of menstrual flui-d. My moisture repellant film former can range in impregnation of the sponge end from completely continuously forming a film in and over the cross-section end area 12 to only partially filling and covering of the fine pore structure of end area 12.

My invention uses dry expanded, regenerated cellulose sponge of fine pore structure as a basic tampon structure material. I define expanded, fine pore regenerated cellulose sponge typically as the dry sponge of fully distended pore structure, not yet subjected to a compressive force which collapses the pore structure.

Typically, my white, regenerated cellulose sponge has pores in the dry, expanded state ranging from 0.5 to 2.0 mm. diameter and the like, and a 1 mm. pore diameter is common. A typical dry, expanded regenerated cellulose sponge density is 0.0296 g./ cc. When fully saturated with water, the typical regenerated cellulose sponge density is 1.00 g./cc., so a fully saturated wet sponge absorbs approximately 0.97 g./cc. of water or relatively similar density menstrual fluid.

My method of tampon manufacture, as disclosed in my copending patent application of this application date titled Sampson Manufacture, teaches manufacturing multiple numbers of tampons simultaneously from a billet of regenerated cellulose sponge. Typically I use a fine pore, expanded, regenerated cellulose sponge billet, such as 11 x 11 inch or the like billet face, having a 2% inch thickness. I treat one of the two parallel 11 x 11 inch billet faces as outlined below in detail, to first prepare a menstrual fluid resistant shield on the billet for a multiple lot of tampons.

Then I complete the lot of tampons in accordance with my invention Tampon Manufacture. I do not wish to be limited in this invention to the manufacturing process or machine disclosed and claimed in my copending patent application Tampon Manufacture. I may separately treat single or multiple numbers of my tampons to practice this invention.

The fine pore regenerated cellulose sponge billet is by its very nature an excellent and uniform absorber of menstrual fluid, water, and other low viscosity solvents such as the common solvents for the plastic or synthetic film formers. Therefore, it is very difficult to prevent film forming-organic solvent solutions and film forming waterbased emulsions from being evenly and uniformly absorbed throughout a cellulose sponge billet, on applying the film forming solution or emulsion to one face of a sponge billet.

In principle I control the precipitation or coagulation of the film forming, flexible, non-toxic plastic composition in a process which establishes the plastic film in one surface layer or boundary zone of the regenerated cellulose sponge billet. The precipitation of the plastic film former in a sponge surface layer may be carefully controlled by first uniformly wetting the sponge with a first liquid which is miscible in all proportions with the second solvent liquid of the film former solution. It is physically necessary that the first liquid be a poor solvent for the plastic film former.

Secondly, on coating the designated sponge billet, which is prewet with the first liguid, with the second solvent solution of the film former, the plastic film former is precipitated in the designated surface layer of the sponge billet. In brief, the two solvents became miscible and precipitate the plastic film former out of the second solvent liquid at the plane of contact in the surface layer or boundary layer zone of the regenerated cellulose sponge billet.

In a further modification of my process, I may first saturate a regenerated sponge billet with water, or a solution of sodium sulfate in water, or the like non-toxic, neutral salt solution, then apply a water based emulsion of a plastic film former. The water first saturating the sponge billet will prevent rapid migration of the latex emulsion uniformly throughout the sponge billet. In fact, the sodium sulfate, or other simple salt dissolved in the Water, will aid and increase the rate of latex resin coagulation. Heat is rapidly applied to the latex emulsion coated on the pre-wet sponge billet surface layer or boundary zone to aid coagulation and heat sealing of the plastic, flexible film.

By my process I can apply film forming solutions or emulsions to one sponge surface, minimizing penetration into the sponge billet body. My new process embodies these steps as follows:

(1) First, uniformly wet the sponge billet, or at least the sponge surface zone on which the moisture resistant shield is to be formed, with a solvent or solution which will rapidly precipitate the film forming plastic or synthetic resin solids from the film forming solvent or emulsion solvent base.

(2) Then apply in correct dosage the film forming or ganic plastic solution or water based emulsion to the sponge surface on which the moisture resistant shield is to be formed, precipitating or coagulating the film former integrally in the sponge surface zone.

(3) If necessary, heat seal the precipitated or coagulated film former to yield a thin, continuous flexible plastic layer, integrally bonded to the regenerated cellulose sponge cell structure of the top to inch sponge surface layer or boundary zone.

(4) Quickly wash out the uncoagulated, or the unbonded film former which is not heat sealed or permanently secured to the top sponge surface layer.

Thus for film formers such as plasticized cellulose diacetate or the like, I prefer to use a water miscible solvent such as dimethyl ketone. On applying a dimethyl ketone solution of the film former to the water impregnated sponge, the plasticized cellulose diacetate is rapidly precipitated or coagulated integrally in the sponge surface layer. Likewise for film formers such as acrylic resin water-based emulsions, I use a sponge pre-wet with water or a 10 wt. percent sodium chloride solution in order to precipitate the film former latex as applied to the sponge.

A. listing of typical film formers includes dimethyl ketone solutions of such as cellulose diacetate plasticized by triethyl citrate, polyvinyl chloride-vinyl acetate copolymer plasticized with diethyl sebacate, plasticized polyvinyl chloride, and the like. The dimethyl ketone solvent for these coatings is selected for high volatility, miscibility with water, freedom from residual odor and low toxicity. Another modification of menstrual moisture shield film formers are the water-based polymeric resin latices. Typically, the vinyl chloride-acrylic copolymer latices form non-toxic, flexible, light colored film suitable for a moisture shield. The vinyl chloride-vinylidene chloride copolymers also form suitable non-toxic, flexible, light colored film. In addition, the polymeric acrylic latices are very suitable film formers for my menstrual fluid resistant shield.

Still another modification of my menstrual fluid resistant surface is formed by continuous films of plasticized cellulose acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, or ethylene-vinyl acetate copolymer or the like, extruded hot onto and integrally bonding into the surface layer or boundary zone of a dry, expanded regenerated cellulose sponge billet. I may apply heat (typically 250-350 F.) and pressure (up to 2000 p.s.i.) to impregnate and bond a continuous thin (0005-0020 inch) flexible plastic film layer to a billet of cellulose sponge. On applying the high pressure, I will collapse and compress the sponge, but after allowing the plastic filmcellulose sponge laminate to cool, I may simply re-expand the sponge billet by simply wetting the laminate with water. The film-cellulose sponge laminates can provide a substantially non-porous tampon end surface free from leakage of menstrual fluid.

As an example of my process for fabricating a menstrual fluid resistant shield zone, I wet and thoroughly Wash in warm water a white, fine pore, expanded regenerated cellulose sponge billet 6 x 6 inch square and 2% inch thick. I squeeze the billet to damp dryness. An acrylic latex, water based emulsion, is applied to one 6 x 6 inch billet damp face by placing the sponge face on a thin film of latex spread on a flat metal surface. The latex is applied to the sponge face at the dosage of 0.67 gram of latex/ sq. inch of sponge face. The resin concentration in the latex is 50 Wt. percent. The impregnated sponge face is then conductively heated by a heated steel surface, regulated to approximately 250275 F., using a Teflon release sheet in between the sponge face and the heated steel surface. In about 45-60 seconds the heat coagulated acrylic resin forms a smooth, inch thick colorless, flexible, integrally impregnated layer in and on the sponge surface layer. The hot resin impregnated sponge is then quickly thoroughly washed, rinsed and wrung dry several times in warm water, to remove the uncoagulated latex resin. The billet can be dried and further fabricated.

The acrylic resin forms a colorless, flexible, slightly fluid-permeable, integrally impregnated surface on the sponge which can permit outward flow of gases which may be generated in the vagina. Under a few inches water static pressure head, droplets of menstrual fluid will slowly penetrate and filter through the slightly fluidpermeable menstrual fluid resistant shield zone.

With a fabrication technique similar to the above described, I also apply a vinyl chloride-vinylidene chloride internally plasticized copolymer latex to a single face of a 2 /2 inch thick sponge billet at a rate of 0.67 gram/sq. inch, using a latex emulsion containing 50 wt. percent resin. The coagulated and fused resin surface is also about inch thick, slightly yellow and flexible. The resin surface is slightly fluid-permeable.

I roll coat a cellulose diacetate (60 wt. percent) triethyl citrate (40 wt. percent) solution wt. percent resin) in acetone, at the rate of 0.1 gram of diacetate per square inch, to a water wet billet of regenerated cellulose sponge, as outlined above. I first water saturate the sponge billet, and use water-miscible acetone to reduce absorbance of the resin solution into the songe body mass, and to precipitate and coagulate the plasticized resin in the sponge surface layer of about inch thickness. A heated flat metal surface may be used to fuse and further smooth the resin impregnation, if desired.

I may likewise spray the solvent based resin solutions onto the water moistened pre-sponge surface, using standard spraying techniques. By regulating spraying techniques, solvent evaporation, and other factors, it is possible to deposit the resins primarily in the sponge surface layer.

It may be desirable to provide a shield zone which will permit the outward flow of gases through the menstrual shield, when they are generated in the vagina by bacteria, molds and yeasts. It may likewise be desirable to provide a means for excess menstrual fluid to exit from the vagina, if the tampon becomes saturated with fluid, and a hydrostatic head of menstrual fluid begins to accumulate behind the tampon. My slightly fluid-permeable menstrual fluid resistant shield provides a safety-valve menstrual fluid leakage means, which enables the excess fluid to leak out slowly, but allows the tampon to retain a fully saturated dosage of menstrual fluid without leaking.

In my teachings I define a polygonal cylindrical tampon as a tampon which may have a regular polygon crosssection end area, and a circular cross-section end area as one with an infinite number of sides. Typically, the dry, expanded polygonal cylindrical tampons are A, or M2, or 1 inch or the like in diameter across the regular polygon cross-section, and the cylinder is from 2% to 2 inch long or the like. Other sizes of tampons can be made as are required.

I have concurrently disclosed in my copending application filed as of this date, titled Tampon Manufacture, a process for the simultaneous manufacture of a multiplicity of tampons. I can combine the teachings of that invention and the teachings of my above disclosed process for manufacture of a coated surface layer billet of regen- I erated cellulose sponge, to further teach a process for the simultaneous manufacture of a multiplicity of tampons having integral menstrual shields.

In FIGURE 4 I show a dry, expanded, fine pore, regenerated cellulose sponge billet 20, having a first surface side 21, and showing also the vertical sides 22 and 23 in perspective view. The sides 22 and 23, which are at right angles to the side 21, have the sponge height equal to a tampon cylinder length. The surface side 21 has the flexible, plastic film former precipitated in the surface layer or boundary zone 25, forming a menstrual fluid impervious layer. A multiplicity of regular hexagonal tampons 26 can be cut from the billet 20, as taught in my copending application Tampon Manufacture, each tampon having a menstrual shield cut from the surface layer 25. I show hexagonal cross section tampon end areas in FIGURE 4, as they represent a maximum usage of sponge billet material, when the honeycomb geometry spacing of cutting dies are used. I may also use round cutting dies, closely spaced, or other shapes.

Typical absorption tests have been performed by females, using tampons of my invention Tampon Manufacture, which have been modified by my integral menstrual shield invention of this disclosure. The results of two tests are reported below in Table I. The tampons were reported by the females as performing very satisfactorily, without leakage or mechanical discomfort.

TABLE I.-TAMPON PERFORMANCE [Test N0. 1 Tampon size: inch round x 2 inch long. Dry blank tampon weight, 1.0 g. Menstrual shield composition was vinyl-chlorideacrylic ester copolymer] Tampon Day of Menstru- Time of Tampon Tampon Weight N0. ation Period Removal (grams) [Test No. 2Tamp0n size: inch round x 2% inch long. Dry blank tarlnponlweight, 1.0 g. Menstrual shield composition was acrylic ester p0 ymer Obviously many modifications of my invention may be made within the spirit and the scope of the teachings I have disclosed herein.

I claim:

1. In a polygonal cross section, one-piece, cylindrical, fine pore, regenerated cellulose sponge tampon, having a withdrawal string handle extending from one tampon end, the improvement which comprises an integral, menstrual fluid resistant, thin plastic layer completely covering the polygonal cross section end of said tampon from which said withdrawal string handle extends, said plastic layer forming an integral bond with the sponge cell structure in said end and penetrating said end to a depth of from to inch.

2. A process for fabricating a menstrual shield in a regenerated cellulose sponge billet comprising: first, uniformly wetting a regenerated cellulose sponge billet with a first liquid in a required dosage; then applying a required dosage of a solution of a non-toxic, flexible, plas tic film former to one surface layer of said sponge billet, said solution containing a second solvent liquid readily rnisciblewith said first liquid, whereby said plastic film former is precipitated as a continuous layer in said one surface layer of said sponge billet; and rapidly washing said liquids out of said sponge billet.

3. A process of claim 2, wherein a first solvent is water and said plastic film former is applied in a water-base emulsion; and said precipitation of said film former is aided by application of heat.

4. The process of claim 2 in which said sponge billet, after being provided with said plastic film shield on one surface is cut simultaneously into a multiplicity of tampons of polygonal cross section.

References Cited UNITED STATES PATENTS 2,458,685 1/1949 Crockford 128263 2,880,726 4/1959 Stieg 128285 2,884,925 5/1959 Meynier 128285 2,998,010 8/1961 Griswold et a1. 128-285 3,347,237 10/1967 Jones l28285 3,368,014 2/1968 Tijunelis 264321 CHARLES F. RQSENBAUM, Primary Examiner US. Cl. X.R. 264321

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