US 2849000 A
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Description (OCR text may contain errors)
Aug. 26, 1958 A. w. Ll-:wlNG
TAMPONS AND THE LIKE k Puk FR EDSSNN Filed June 8. 1953 47 amm TW mi QNVL mw a. w f waa QO. n. p u o W 8d m w 1 1% ATTOR EYS TAMPONS AND THE LIKE .Albert W. Lewing, Monson, Mass., assignor to Tampax,
Incorporated, Palmer, Mass., a corporation of Delaware v Application June 8, 1953, Serial No. 360,071
11 Claims. (Cl. 12S- 285) This invention relates to body fluid absorption device and more particularly to a compressed mass of treated absorbent liber-s formed into a tampon or the like for insertion into a body cavity and adapted for increased absorption and Aretention of body fluid. This application is a continuation-in-part of my copending applications Serial Nos. 188,921 and 188,935, both filed October 7, 1950, both now replaced by continuation-in-part applications.
In the manufacture of body fiuid absorption devices such as vaginal tampons, dental rolls, surgical pads, arid the like, from, for example, a mass of absorbent cotton fibers, it is possible to increase the absorption capacity of the iibrous material by special treatment of the cotton, control of density `of the cotton mass, etc. Suchtreatments, however, often fail to increase the capacity of the fibrous mass for retaining fluid absorbed against the intermittent squeezing such as that to which a vaginal tampon is subjected `during use by the normalmovement and activity of the wearer, or a dental roll by muscular movement of the cheek or pressure from the dentist while working. ln fact, many treatments of absorbent cotton whi-ch improve its absorbency have by the same action facilitated the ease with which absorbed fiuid can be expelled or squeezed out of the cotton. p
According to this invention, it has been discovered that an improved absorption device lof the character described can be produced using an unspun mass of 4absorbent cotton as the absorbing medium by treating the cotton fibers with retention agents as set forth herein, land that such treatment not only increases the absorbency of the cotton for body lluid, but also increases the amount of body fluid which a given amount of cotton fiber will retain against normal squeezing.
lt is accordingly a principal object of this invention to provide an improved body fluid absorption device of atent O 2,849,000 Patented Aug. 26, 1958 the following description, the accompanying drawing and the appended claims.
y In the drawing:
Fig. 1 is an isometric view of a vaginal tampon embodying this invention;
Fig. 2 is a view partly in axial section, of the tampon of Fig. l and Fig. 3 is a graph showing a series of comparative clinical test results with vaginal tampons embodying this invention.
Referring to the drawing, Figs. l and 2 show, as illustrative of one embodiment of this invention, a vaginal tampon adapted to be inserted into the vagina. Tampons and the like which may be inserted into the vaginal cavity have been in common use for many years and have been increasingly recognized as a superior means for caring for the menstrual flow. A convenient and desirable absorbing medium from which such an insertable tampon may be made is a mass of unspun absorbent cotton. Such fibers are conveniently compressed into a more or less cylindrical mass of more or less rigid form and size for ready insertion into the cavity.
With such tampons of a size comfortable to the wearer, their value to the wearer depends upon the length of time during which they effectively absorb and hold all the menstrual flow.
According to this invention, a mass of absorbent fibers is treated with retention agents as set out below and. such treatment greatly enhances the capa-city of the mass not only to absorb more fluid but also to carry and retain partly in plan,
- more fluid against expulsion by squeezing forces. As a result, a satisfactory tampon of given size gives more effective service or one of smaller size capable of the same service can be produced according to this invention. `As illustrative of the results obtained with absorption devices embodying this invention, it has been found by clinical tests that such tampons of a conveniently small size, when worn for a prescribed period much longer than is permissible with existing tampons, are capable of absorbing and retaining all catamenial fluid and providing a high safety factor so that possibility of leakage, soiled clothing or other embarrassment is precluded.
Thus, it has been discovered and demonstrated as a result of clinical tests, that approximately six to eight grams of catamenial fluid represents an average flow during four to ve hours of the menstrual period and that the character described having improved capacity` for i absorbing and retaining fluid under normal conditions of use. v Y
Another object of this invention is to provide an improved vaginal tampon of the character described including an unspun mass of treated absorbent fibers and having a greater capacity for retaining catamenial fluid against expulsion by squeezing than a similar tampon of untreated cotton. l
A further object of this invention is to provide an absorption device of the character described for insertion into a body cavity and having a smaller bulk for a given body fluid absorption and retention capacity.
Still another object of this invention is to provide for the manufacture Vof fluid absorption devices of the character described to increase the capacities of such devices for fluid retention under normal conditions of use.
Still another object of this invention is to provide materials and methods for treating absorbent fibers to produce iiuid absorption devices of the character described having Such improved fluid retention capacities.
Other objects and advantages will be apparent from twelve to fourteen grams represents an approximation of the heaviest menstrual flow normally encountered in that length of time. Since four to iive hours appears to be the usual and convenient period for wearing a single tampon, such period has here been taken as standard for purposes of demonstrating and comparing the advantageous results of this invention. For these same purposes, the expression percent protection is used herein as meaning that percentage of the tampons clinically evaluated which were reported by the user as giving complete protection (i. e., no leakage or discoloration of clothing, etc.) during the reported use.
Such clinical evaluation with the three normally used sizes of tampons emphasizes the advantages of this invention:
(l) With the large size tampon of the highest quality sold commercially prior to this invention, the percent protection drops to when the dow during the use of the tampon increases to six or eight grams, and percent protection drops to 20% when the How increases above the twelve to fourteen gram range. A tampon of the same weight of the same cotton but embodying this invention, having been treated with glycerine as described hereinafter, gives protection throughout the six to eight gram range, and the percent protection does not drop even as low Aas`90% until the flow increases above the fourteen to sixteen gram range.
(2) The percent protection with the medium size untreated tampon of highest commercially available quality dropsto 90% at the six to eight Vgram -ra'ngeand'asd'w as 20% above the twelve to fourteen 'gram"i"a'n"ge. 'But identical tampons treated with glycerine so as 'tofembody this'inveritionprvide 99% Vprotectio'n thro1'1'g`r-1'o'ut the six to eight gram range, do not drp `be1ow'90'% protection until abovethe ten to"twelve gram `1"ai:ig`e,V and still offer 80% protection throughout the fourteen to sixteengram range. A
(3) The percentproteetion of untreated highestcrnmercial quality tampons of the smallest size dropsaslow as'about v80% "even in the range six 'to eight grams'of flow, and as Alowias about y45% in the eight to' ten gram range. Identieal tampons treated with lglycerine to embody this invention provide 100%fp`r'otection up to eight grams of flow and 80% protection up to ten grams of flow. y
It should be4 noted that the clinical method necessarily used for 'test involves differences in personal activity and dilerences in flow, etc., such that about a difference of 2-3% 'in percent protection must be regarded as within the expected experimental error. However, Vwhen the percent protection drops below 95% it is serious and'rnay not be disregarded.
Figure'3 is a graph showing such comparative clinical test Aresults with identical tamponssome of which are treated with glycerine, some with ethylene glycol, some with propylene-glycol and some with polyethyleneV glycol, all vaccording to the present invention. 'Each tampon was worn by a menstrating woman in the usual manner. Each was weighed before use and upon removal, and upon removal determination was made as to any evidence that menstrual iluid had escaped. YThe used tamponsw'ere grouped'according to the weight of 'the fluid absorbed and the'pereent'a'ge of those in eaehgi'oup which'had allowed no"exte`r`nal evidence `of` menstrual flow was recorded, and plotted on Figure 3 as percent protection.
Although the 'exact explanation of how or why"'the liquid retention Acapacities of tampons are so increased by treatment according to this invention is not now cert'ainly known, vuseful hypothesis can be'rnade. For example, it is thought that wetting 'agentA action is not responsible for theadvant'a'gesl of this invention, since experiments 4with wetting agents have indicated"`that, although more fluidmaybe absorbed, thewetting agent tends to cause excess fluid to'be more readily squeezed out ofthe 'tampon just' as it is 'more readily absorbed, thereby reducing rather A'than increasing the 'retention capacity; whereas the 'protection 'effected by uid retention, as 4shown by the 'above mentioned tests; are'far beyond anyim'provement shown by laboratory 'tests on absorbency or capacity to take up and-hold the 'test fluid 'dripped onto the tampon.
It is to be` 'noted that the retention agentes V'of this.l 'invention apparently become 4more strongly bonded 'to the cotton fibers themselves than can Vbe explained by mere wetting or absorption and, althoughl retained "on the surface of the bers, appear to producea'relatively low surface action on v'uids absorbed "bythe' mass`of fibers. For example, untreated absorbent cottonwill hold approximately 18 -to 20 times its weight ofwater, but such water is easily squeezed out. On the``oth'er hand, cotton from thel same batch whentreatedacording to this invention will absorb approximately %'y more fluid than the untreated cotton, but the treated `vtampon will provide as muchas 50% greaterretention-in a tampon, and protection to the wearer. lt isnoted, furthermore, that, although-somesatisfactory-retention agents according to this invention mayA have certain wetting agent properties, all wetting agents do not' produce satisfactory retention andfconversely, v-materials which' do produce satisfactory VVresults' are not generally included in the class of so-called wetting agents. What is wanted is something which will cause the uid to spread over the fibers rapidly and yet hold it against draining or squeezing. It appears that something analogous to chemical bonding occurs and the presence of hydrophil'groups is believed to be significant, especially OH groups and especially with such groups `at opposite ends of the molecule. Thus, it is evident that the polyhydric alcohols and their esters are most effective to improve retention of the absorbed. uid.
Representative concentrations Vand materials of the class of retention agents which have been found to produce satisfactory-.results.according to this invention are:
Also 'uidpolye'thylene `glycols (e. g., those of approximately 200 to 400 molecular weight) have been found satisfactory. Such retention'agents are all hydrophilic, water` soluble" polyhydric materials Particularly with vaginal ta'rnpons and the like, theretention agents should also'be substantially'physiologically inert and without deleterious effect'onbenign/ organisms normally and desirablypre'sent in the body' cavity in which the tampon is`worn. The'higher molecular weight, more or less solid or waxy polyethylene glycols (e. g., vof approximately 1500 molecular weight) 'have' beenfound vto give good retention'capaciti'es toabsorbent cotton in concentrations of from 5 to 2%, although the consistency of such materials has been found to 'introduce some difficulty into thecarding operation' of processing the absorbent cotton.
I'have also found that wetting agents (e. g., Nacconal, a'sulfonated'aryl alkylwetting agent)can be used to hasten absorption 'incombination with one of the retention agents, without impairing the retention action. The wetting agent improves the wicking action of the cotton, which takes' vcare of cases of so-called gushing ow. Without'this improved wicking action, a tampon would vfail to give complete protection against such gushing How although it would still have adequate capacity for further absorption of normal menstrual ow.
The above noted' concentrations are on the air dry weight of the cotton (i. e., with about 5% moisture in the" cotton). As illustrative of appropriate concentration ranges, it has been found that glycerine, for example, may advantageously be applied within the range of from .1%to about 15% as noted. In this range the absorbency and retention capacities of the cotton are significantly increased but to varying degrees. With glycerine concentrationssubstantially'above this range, however, an impairment of dimensional stability of compressed tampons, Vand to 'some extent also, an actual diminution of 'absorbing capacity is noted. A final concentration on the completed tampon of approximately .25% to .75% ofglycerine on the air dry weight of the cotton has been foundV most advantageous for commercial use. Although lower and higher concentrations Vof glycerineincrease the absorbency capacity of the cotton, it has been noted that the range'of theorder'of .5% (46% for practical operation) Vglycerine produces'the greatest increase in retention capacity. Substantially higher concentrations provide anincrease of retention capacity, although it has been found'that the increase attributable to substantially higher concentrations of glycerine in many cases does not warrant the c'st of'the 4additional treating material. In concentrations above,approximately 20%, the presence of glycerine on the fibers is apparent to the touch, and this may render a tampon so treated unpleasant to handle or undesirable from a commercial standpoint. In this connection it should be noted that the amount of retention agents applied is only that which will treat the surfaces of the individual fibers; and distinction must be drawn between a tampon so treated with a retention agent and a tampon carrying so much of such agent that an appreciable portion of the interstices between fibers available for absorbing body fiuid is occupied by the retention agent.
The retention agent is advantageously applied to unspun absorbent cotton fibers before they are cut and formed into a tampon. Satisfactory results have been obtained by adding the retention agent to the water in the final Washing step in the process of manufacturing and preparing absorbent cotton bats to be used in manufacture of tampons.
Thus, a glycerine in water wash solution may be applied to the cotton instead of the usual wash solution in the usual manner, e. g., by spraying the bat imme- -diately ahead of the final squeeze rolls just prior to drying. It has been found that approximately 100 cc. of glycerine-Water solution is retained after squeezing by approximately 100 grams of absorbent cotton in this process. In situations where the viscosity of the retention agent is sufficiently low to penetrate the mass of cotton fibers satisfactorily (e. g., where the process is carried out at sufficiently elevated temperatures and/or the fiber is Wet at the time of application) undiluted agent may be directly applied to the cotton as by spraying. Also, other solvents than Water (e. g., alcohol) may satisfactorily be used in the treating solution but water is preferred, since it obviates many problems of solvent elimination and recovery.
After the retention agent is applied, the bers are dried to remove the solvent by any convenient means such as passing the cotton on a conveyor through a drying tunnel with circulation of warm air. Satisfactory results are obtained where the temperature at the wet end of the tunnel is approximately 240 F. and approximately 212 F. at the dry end, with the cotton passing through this range of temperatures in approximately one-half hour.
It should be noted that a substantial percentage of the agent originally applied to the cotton may be lost by evaporation along with the water during the drying procedure. It has been determined, for example, that cotton initially containing glycerine in concentrations of 0.5% to 10%, when dried at 240 F. for four hours may lose as much as 50 to 75% of this initially retained glycerine. Utilizing the half hour drying procedure described above, the cotton fibers may lose as much as 50% of the glycerine. It has been determined, however, that, when the remaining glycerine concentration is reduced to approximately .37%, it appears to be quite stably bound to the fibers and no further substantial loss of glycerine occurs even after heating many hours at 260 F. Such expected losses should be taken into consideration in determining the amount of glycerine applied, in order to achieve the desired concentration on the fibers of the finished tampons.
After the uncut and unformed bats of absorbent cotton fibers are completely processed and treated with the material as noted above, the bats may be cut into pads or tampons and, if desired, may be compressively formed into a desired size and shape by conventional means. By way of illustration, a convenient method of forming absorbent cotton fibers into a compressed, generally cylindrical tampon is indicated in the patents to Voss, No. 2,076,389, April 6, 1937, and McLaughlin No. 2,416,706, March 4, 1947. As shown by these patents, the loose cotton bats or tampon blanks are fed in between compression dies which impart thereto the desired cylindrical shape and degree of compression. They are thence ejected into cylindrical chambers where their compression and shape are maintained while heat is applied to set the fibers thereof in their compressed form. In cornmercial practice tampons embodying this invention have been produced in three general size groups, e. g., containing approximately 3.1 grams, 2.3 grams and 1.4 grams of cotton.
It will also be understood that the treating material may satisfactorily be applied to the cotton at some stage in the processing thereof other than during the last washing step as described above. The conventional mill operations, e. g., carding, to which absorbent cotton is usually subjected after washing and drying have been found, because of the mechanical working involved, to distribute the retention agent throughout the cotton mass. The retention agent may be satisfactorily applied, however, at any convenient stage of the cotton processing when the fiber mass is sufficiently open or the individual fibers sufficiently exposed to obtain effective application and distribution. Any subsequent loss by evaporation or washing, however, should be taken into consideration.
l. An improved vaginal tampon adapted for catamenial fluid absorption and retention under normal conditions of use within a vaginal c avity comprising as a fluid absorbing and retaining means a compressed mass of absorbent cotton fibers, said fibers carrying substantially uniformly distributed thereover a hydrophilic, nontoxic, polyhydric alcohol, retention agent.
2. An improved vaginal tampon adapted for catamenial fluid absorption and retention under normal conditions of use within a vaginal cavity comprising as a fluid absorbing and retaining means a compressed mass of absorbent cotton fibers, said fibers carrying substantially uniformly distributed thereover a fluid, nontoxic, hydrophilic, polyhydric alcohol retention agent selected from the class consisting of sorbitol, mannitol, glycerine, glycols and glycol polymers.
3. An improved vaginal tampon adapted for catamenial fluid absorption and retention under normal conditions of use Within a vaginal cavity comprising as a fiuid absorbing and retaining means a compressed mass of absorbent cotton fibers, said fibers carrying approximately 0.1% to 15% by weight of a retention agent selected from the class consisting of sorbitol, mannitol, glycerine, glycols, and glycol polymers.
4. A device for absorption and retention of body fluids comprising as a fluid absorbing and retaining means a compressed mass of absorbent fibers having the absorption and retention capacity thereof increased by impregnation with a fiuid hydrophilic material selected from the class consisting of glycerine, glycols, glycol polymers, sorbitol, and mannitol, said materials being distributed over said fibers in an amount less than about 15% of the air dry weight of said fibers.
5. An improved vaginal tampon adapted for catamenial fiuid absorption and retention under normal conditions of use within a vaginal cavity comprising as a fluid absorbing and retaining means a compressed mass of absorbent cotton fibers, said fibers carrying glycerine as a retention agent in an amount approximately 0.25% to 1% of the air dry weight of said cotton.
6. An improved vaginal tampon adapted for catamenial fluid absorption and retention under normal conditions of use within a vaginal cavity comprising as a iiuid absorbing and retaining means a compressed mass of absorbent cotton libers, said fibers carrying a fiuid glycol retention agent in an amount approximately 0.25% to 1% of the air dry weight of said cotton.
7. An improved vaginal tampon adapted for catamenial fluid absorption and retention under normal conditions of use within a vaginal cavity comprising as a fluid absorbing and retaining means a compressed mass of absorbent cotton fbers, said fibers carrying glycerine as a retention agent in an amount approximately 0.1% to` 15 of the air dry weight of said cotton.
8, An improved vaginal tampon adapted for cat arnenial fluid absorption and retention under normal conditions of use within a vaginal cavity comprising as a ud absorbing and retaining means a compressed mass of absorbent cotton fibers, said fibers carrying glycerine as a retention agent in an amount approximately 0.4% to 0.6% of the air dry weight of said cotton.
9. An absorption device for insertion into a body cavity and adapted for body fluid absorption and retention under normal conditions of use comprising as a body fluid absorbing means a compressed mass of absorbent cotton fibers, said fibers carrying as a retention increasing agent ethylene' glycol inan amount approximately 0.25% to 1% of the air dry weight of said cotton.
10. An absorption device for insertion into a body cavity and adapted for body uid absorption and retention under normal conditions of use comprising as a body fluid absorbing means a compressed mass of absorbent cotton fibers, said fibers carrying as a retention increasing agent ethylene glycol in an amount approximately 0.4% to 0.6% of the air dry weight of said cotton.
11. An absorption device for insertion into a body cavity and adapted for body fluid absorption and retention under normal conditions of use comprising as a body fluid absorbing means a compressed mass of absorbent cotton fibers, said fibers carrying as a retention increasing agent a uid polyethylene glycol in an amount approximately 0.25% to 1% of the air dry Weight of said cotton.
References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS 112,192 Germany June 6, 1900 537,113 G reat Britain lune 10, 1941 550,638 Great Britain Jan. 18, 1943