US3264691A - Method of making tampons - Google Patents

Description

ugu 9, 1966 H. A. WHlTEHEAD 3,24Q

METHOD 0F MAKING TAMPoNs Filed Nov. 24, 1964 United States Patent Office Patented August 9, 1966 3,264,691 METHOD F MAKING TAMPONS Howard A. Whitehead, Appleton, Wis., assgnor to Kimberly-Clark Corporation, Neenah, Wis., a corporation of Delaware Filed Nov. Z4, 1964, Ser. No. 416,951 1 Claim. (Cl. 19144.5)

This is a continuation-impart of application Serial No. 219,395, filed August 27, 1962, now abandoned.

This invention relates to improved techniques for the fabrication of catamenial tampons and to resultant improved products.

A primary object of the invention resides in the provination of the drawings and description.

In the drawings, in which like parts are identified by the same reference numeral,

FIG. 1 is a perspective view of a strip of Huid-absorbent base stock prior to being cut into tampon pledgets.

FIG. 2 is a perspective view of a pledget of keystone configuration as cut from the blank of FIG. 1.

FIG. 3 illustrates one manner in which tampon withdrawal strings are fastened to the individual pledgets of FIG. 2.

FIG. 4 illustrates in front elevation a funnel suitable for compressing the batt of FIG. 3.

FIG. 5 is a view in side elevation of the funnel of FIG. 4.

FIG. 6 is a sectional view of the funnel of FIGS. 4 and 5 taken at 6 6, FIG. 4.

FIG. 7 illustrates in perspective a tampon fabricated by the method herein taught.

The concept of employing certain types of sponge materials as the absorbent element in catamential tampons is suggested in the prior art. For example, Crockford Patents Nos. 2,254,272 and 2,458,685 are each directed to the employment in tampons of cellulosic sponge of the type produced from a viscose base. However, both Crockford patents, as well as all prior art teachings known to applicant which teach cutting a batt from sponge-like material, contemplate a material which has been completely dried prior to cutting. Thereafter the dry pledget is compressed into a cylindrical or other desired configuration.

During the more than twenty years which have elapsed since the issuance ofthe Crockford Patent 2,254,272, such sponge materials have failed, so far as is known, to come into use, at least on a commercial production basis, either in this country or abroad. During that same period tampons consisting either entirely of natural fibers such as cotton fibers or of blends of natural fibers and synthetic fibers, have enjoyed a wide and substantially increasing acceptance in the U.S. and in certain foreign countries. The failure of sponge type materials seriously to compete with fibrous materials is believed based on the somewhat higher cost of sponge materials coupled with the fact that heretofore no marked advantages were evidence to justify the resulting price differential. The invention taught herein permits the fabrication of sponge tampons of greatly improved anatomical design and absorbent capacity, and which may be sold within or only slightly beyond the price range of fibrous batt tampons.

The concept of preforming a tampon batt from slabs or sheets of dry cellulose spongeis disclosed in Crockford Patent 2,458,685. For example, a plurality of batts of keystone configuration may be cut from sheet stock,

a withdrawal string applied medially thereto by sewing or the like, and the batt thereafterrolled into somewhat helical configuration and inserted into a cylindrical die or directly into a tubular applicator. The tampon is adapted for insertion into the vaginal canal with the larger end thereof innermost, the cylindrical tampon body being suitably compressed to remain form-sustaining until contacted by iiuids with a resultant gradual unwinding of the helical batt. While Crockford states that he positions the larger end of the batt adjacent the uterus where it is most needed, it has since been learned that a keystone configulration best conforms to the vaginal cavity which convergently narrows downwardly from a position adjacent the uterus. It is further known that the collapsed tube forming the cavity is of a generally dumbbell configuration in transverse section.

While in theory an unrestricted helically wound batt might unwind, when fluid saturated, back into its initial planar shape, it has been established, as the result of extended research (including X-ray photographs) that pressures exerted by the vaginal tissue folds on a helically wound sponge tampon, as taught by Crockford, are of a magnitude to prevent unwinding of the pledget back into planar configuration. In other words, investigations have shown that the vaginal tract normally is restricted in expansion in the vertical plane both structurally and physiologically by the bladder and the rectum. At the same time, there is virtually no structural or physiological restriction to expansion in the lateral plane. It has been found that a compressed tampon which re-expands primarily in the lateral direction during use provides a better anatomical fit and offers more absorbent protection. A tampon produced by the method herein taught has these improved characteristics.

As shown in FIGS. 2 and 3 of Crockford, the relatively thin dry sheet sponge is formed into a comparatively wide pledget to permit helical wind-up as shown in FIG. 8. Crockfords major pledget base 5 is of greater dimension than his pledget axis along which thread 7 is sewn at 6. In marked contrast to the Crockford teaching, applicants pledget, as shown in FIGS. 2 and 3, is of a length substantially greater than the width of the major base thereof. Assuming the same amount of sponge material employed to produce each type tampon, Crockford starts with an initially thin pledget whereas applicant starts with a much thicker pledget which is also substantially narrower than the Crockford pledget even though the two pledgets may contain the same amount of material. .The length may actually be the same (say, for example, two inches) but in that instance Crockfords major base dimension may be greater than two inches, and perhaps two and one-half inches; whereas applicants major base dimension is less than two inches and, for example, one and one-half inches.

As shown in FIG. 1, an elongate strip 10 of wet spongelike material such as viscose sponge is cut along dotted lines 12 to form a keystone-shaped pledget 14. Pledget 14 preferably is cut from a relatively thick strip of wet sponge, for example from a strip two inches wide and from one-half to one inch in thickness, and preferably at least about M inch thick. The resulting pledgets of two-inch length may, for example, have a major base 16 approximately one and one-half inches wide and a minor base 18 approximately two-thirds of an inch wide. Pledget 14 is next provided with a withdrawal string 20, FIG. 3, which preferably is sewn thereto along either a single line or the pair of spaced lines 22, 24 as shown. String 20 may consist of one or more twisted threads with the resulting string extending beyond minor base 18 a desired amount as hereinafter described. While parallel lines of stitching are shown, they need not be parallel, and may converge from the major to the minor base in of the applicator.

FIGS. 4, 5 and 6 illustrate the manner in which theV pledget of FIG. y3 is compressed into cylindrical configuration by being drawn through a flattened'fnnnel 26. `The mouth of funnel 26 tional configuration Vand leads into a cylindrical terminal portion 28. A tubular connector 30 is employed to effect abutment between cylindrical funnel portion 28 and a tubular applicator 32 into which pledget 14 is ultimately deposited. The interior diameter of applicator 32,is substantially equal to or slightly greater than the .interior diameter of cylindrical portion 28 of funnel 26.

Withdrawal string 20,.FIG. 3, is of permit extension thereof through both attached applicator 32, FIGS.- 4 and 5, and beyond the lower end of applicator 32 sufficiently to permit manual grasping thereof with minor base 18 positioned immediately above the mouth of funnel 26.v Withdrawal string 20 may, if desired, .be fed through -both funnel 26. and applicator 32 by application of suction to the lower end String 20 is of `sufiicient strengthlo permit employment in pulling pledget 14 through tfunnel 26 to effect shaping thereof into cylindricalforrn: and transfer to applicator 32.l

As previously mentioned, pledget 14 is cut from a strip of wetsponge-like material such as viscose sponge. The term wet has lnot been fully dried after `its initial formation. Pledget 14 remainsv wet throughout withdrawal ,string attachment and is of generally rectangularfcross-seA sufficient length to, funnel 26 and the as employed herein means that thesponge the compression thereof resulting from the pledget 14 being shaped as it is pulled by withdrawal string 20 through funnel 26. As best shown in FIGSQS with the aboveteaching may reexpandwhen fluid ,sat-- urated, fully back into rits. initially 'uncompressed con-v and 6, the narrow funnel 26, has a minor dimension equal to the ydiameter of cylindrical portion 28. Applicator tube 32 is approximately equal to the thickness of pledget 14.s

Thus, as pletget 14 is drawn through funnel 26, compressive forces are ofthe pledget. The fiattened.configuration of the mouth and neck of funnelV 26 prevents relative rotational movement of pledget 14 therein, the pledget being dimensioned -to be snugly received therein, hence as the pledget is string drawn through the funnel, it is subjected primarily to compression forces resulting in width rather than thickness reduction. The resulting compressed tampon is thus -asym-v metrical with respect to the direction and the degreey ofy compression. Since more material is present in the plane. corresponding to the transverse axis of the uncompressed tampon, re-expansion forces are primarily lateral. since the original tampon pledget is keystone-shaped, the forward portion of the compressedtampon, is much denserfand capable of greater expansion than is the anteriorl portion. Thus, the structure of the finished tamponis such that in the dry state the cells are more highly compacted in the forepart thereof and become.

gradually less compacted toward the anterior. The com. paction in the finished tampon is also substantially transverse or diametric, as opposed to the radial or circum-` ferential compaction found in ordinary tampons, and, as a result, the tampon, in use, is adapted to expand to its original planar keystone shape to provide a better anatomical fit and an attendant improvement in absorptive protection.

applied primarily across the major plane Also,

as inserted,`

Also, since the fibers in wet cellulose sponge are maintained therein both somewhat swollen and plasticized, they are in a condition to absorb the stresses of compression withoutbeing broken or otherwise damaged as when in a dry state.

While ypledget 14 is preferably formed of Viscose type sponge, the invention is not so limited and contemplatesv other suitable materials which may include certain ma` terials in the foaml category as well as those normally referred to as sponge.; Regardless of whether the ma-v foam or the` .sponge type,v compression into cylindrical configuration while' wet folterialof pledget 14 is of the lowed by drying `results in superior fiuid-induced re-expansion during use. toits original keystone configuration. The improved results thus obtained are believed due, --at least impart, to the plasticizing effect of moisture when present during the compression stage. Such plasticizing can be readily demonstrated by applying severe mechanical impact to fibers in which swelling has-been prevented by cross-linking. The'treatedfibers yrapidly reduce to powder while the control fiber,: soft and plasticized by swelling with water, suffers Vlittle damagel under the same Thus by compressing wet, rather thanY dry, 4.pledget material, the waterl present both swells and plasti conditions,

cizes the fiber-like material .to vrender it `capable .offabsorbingsubstantial mechanical stress without vsustaining the substantial damage which results from the compression of the samernaterial while ina dry state;

A like phenomena may be demonstrated bycomparing the wet and ,dry tensile strengths kof a twistedy cotton yarn. Wet cotton yarneXhibi-ts a higher` strength, attributed to its more swollen and :,plasticized condition, enabling it to better equalizestress concentrations to which' the yarn might be subsequentlysubjected. Inthe same manner a .wet` sponge lmaterialsuch as cellulosic sponge ,is Capable -of distributing v-local stresses'.withoutlfailure ofV either fiber or regenerated `cellulosic membrane. Thus, a pledgetof viscose `typecellulosic sponge or the like compressed into; cylindrical iconfiguration. in accordance figuration; However,e the same=pledget, if compressed while dry, can at best only ypartially re-expand towards its initial configuration.

Sincepledget 14 is compressed inthe Wet state, the

invention contemplates employmentof an applicator .of plasticV .or thevlike which is not affected by moisture.

After compression,` the applicator-enclosed tampon,

FIG.;7, may be Vdried by dielectric` .heating or the like portion of .eachpledget'sutiiciently to. effect a generally dumbbell configuration'in cross narrowend of said wetpledget by section, ,drawing the tapering guide member havingthe general configuration of a flattened funnel whereby said pledget is constrained with respect to said against relative Yrotational movement casingwhile/` being compressedlsubstantially only transversely of the major planey thereof into thejcylindrical shape of said applicatorcasing, and thereafter drying said casing-enclosed pledget;

References .Cited by the; Examiner UNITED 'STATES PATENTS 2,254,272 9/ 1941 Crockford a 12S-285 2,710,007 6/1955 Greineret al 12S- 285 X 2,926,394 3/ 1960 Blet-zinger et al 19-1445 ROBERT R. MACKEY, Primary Examiner.v RICHARD A. GAUDET, Examiner.

C. F. ROSENBAUM, ED. NEWTON, Assistant Examiners.

4tampons comprising the steps:

said .withdrawal stringA intoa cylindrical applica-torcasing through an inwardlyV

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