CA1084201A - Tampons - Google Patents

Abstract

Abstract of the Disclosure:

A tampon for the absorption of body fluids is in the form of an annular or sleeve shaped bag carrying an absorbent material within the tray. The absorbent material is in the form of a sandwich comprising two carrier layers with an absorbent gel material held between these layers. The gel can therefore be more easily handled during manufacture as well as having greater protection against gel particle fall-out in use.

Description

The present invention relates to tampons for the absorption of body fluids, particularly catamenial tampons.
Highly absorbent gel materials such as modified celluloses and starches and polyacrylonitrils materials have been proposed for use in tampons, however it is difficult to ensure that auring manufacture the materials are located and maintained in the correct position within .
the tampon, and also it is difficulk to arrange for the best utilizati.on of these materials during conditions of use.
Suitable gel materials of this type have been disclosed in German Patent Application P 26 36 899.0 in the name of N.J.T. Melican and laid open to public inspection on March 10, 1977 and in US Patents 3,589,364, issued to Buckeye Cellulose Corp. on June 29, 1971, 3,661,815 issued to Grain Processing Corp. on May 9, 1972, 3,669,103 issued to Dow Chemical Co. on June 13, 1972 and 3,670,731 issued to Johnson & Johnson on June 20, 1972.
It has been found in practice that tampons formed in .a hollow conical shape are particularly effective when incorporating such highly absorbent gel materials; and the present invention provides such an arrangement where the gel can be handled conveniPntly during manufacture and is maintained in an effective location within the tampon itself both prior to, and also during use.
Accordingly the present invention provides a hollow conicàl tampon comprising an absorbent inner material in the form of ~i=' an annular sleeve enclosed wi~hin the inner and outer layers o : .,~. : : , -:- : : , .
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an annular shaped bag of Eluid pervlous materia]., said absorbent inner material being in the form of a sandwlch comprising a quantity of absorbent gel material held between two carrier layers at least one of which is of a fibrous material having capillarity and serving as a temporary reservoir to carry the fluid until it has been absorbed by the gel material.

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The tampon c~n be manu~acturecl by firstly ~orming the sand~ich of carrier layers with the gel hel~ therebetween.
This can be effected, in one particular method, by ~ bringing two layers o~ carrier ma$erial together between a pair of rollers and applying the gel at the zone o~
the nip of the two rollers ~o a~ to form a gel coating between said layers. Moisture and heat, ~or e~ample from steam, may be used to bond the gel coating within the layers.
The gel may be a continuous layer coating or may be in $he form o~ stripes if directional spread/absorption is required. ~he gel material may be on its own as a sur~ace coating bonded to at least one o~ said carrier layers or may be h~ld within a separate inner layer, which inner layer comprises a mixture o~ the gel material and a wicking ~iller material such as textile or wood pulp fibres~ or polyurethane ~oam which as well as promoting wicki~g ~flow and spread by capillarity) may increase gel binding, resiliency and product performance.
Conveniently the ~orming o~ the sleeve tampon with the absorbent sandwich may be e~ected on an elongate mandrel which is at least partly hollow.
One or more layers of the absorbent sandwich may be ~ormed into a ~irst tubular sleeve (pre~erably on the mandrel), a layer o~ pervious material for the outer bag may then be ~ormed as a second tubular sleeve over the first $ubular sleeve in such a manner as to have a , :
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~ Z ~ cZ.174 longituc~inal length about twice (usually slightly greater than twice) the length of the ultimate tampon and with half of sai~ length overlapping at one ~nd of the first tubular sleeve. The overlapping length may then be introverted along the inside o~ the first tubular sleeve (this can be done by an air pressur~ jet or by vacuum or by a mechanical probe~ to ~orm a sleeve shaped bag enclosing the ~irst tubular sleeve, The two ends of the bag ~aterial then come together and m~y be tied to a withdrawal cord in conventional manner, As an alternative to ~oxming the bag material over the ~irst tubular sleeve ~of sandwich layer material), the bag material may start as the underneath layer and be ~olded back externally over the overlaying t~bular ~leeve lS o~ sandwich layer materials.
The resultant tampon may then be compressed and inserted in a cardboard tubular inserter in a manner known per se.
A particular advantage o~ this ma~u~acturing method is that the gel material, which may include small particles is handled in a manner which ensures that an even layer or an even stripea coating, is located where it is wanted without gel powder or particles flaking o~, i.e. there i9 control o~ the handling o~ the material by virtue o~ the outer covering layers o~ the ~andwich.

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cZ.17 Xn use there are ~urther and more important advantages.
An important advantage of -the tampon construction in its broadest sense is that in use the layer of gel material is protected against any risk of particle ~all out by having at least two layers of material (i~e. a layer of carrier material and a layer o~
the outer bag material) between it and the exterior.
~hus there is at least a double layer protection to 0n~ure that loose particles o~ gel material will remain within the tampon and be removed with the tampon after use.
Moreover, the arrangement holds the whole structure together better in use, i.e. the gel and carrier has lS greater structural i~tegrity during that use.
Gel materials o~ the ~ind previously mentioned have the property o~ absorbing large quantities o~
liquid. However they take up this liquid comparatively slowly~ By sandwiching the gel material between two carrier layers at least one of w}ich has capillarity the capillary layer or layers can serve both as a Gonductor of the liquid -~rom outside to the gel absorbent material, and also as an intermediate reservoir to carry the liquid until it has been absorbed by the gel.
The arrangement where layers having capillarity are used is particula.rly advantageous when using a cross-linked carboxy-alkylated starch ba~ed material of the kind disclosed in :- German Pate~t Application P 26 36 899Ø

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An embodiment of the invention will now be described by way of example with reference to the accompanying diagrammatic draw-ings in which:
Figure 1 is a schematic dia~ram oE an equipment for making a sandwich of tissues incorporatiny ahsorbent gel;
Figure 2 is a perspective view showing how the sandwich and an outer layer are formed on a mandrel;
Figure 3 is a view of the end of the mandrel showing forma-tion of the tampon; ~ , Figure 4 is a similar view to Figure 3 at a different opera-tional stage; and Figure 5 is a diagrammatic representation of the tampon so formed.
Referring to Figure 1 a hopper 1 contains a suitable highly absorbent milled particulatecross-linked carboxyalkylated starch starch derivative gel. The manufacture of such gels is described in the afore-mentioned German Patent Application P 26 36 899Ø
A vibratory feeder 2 is arranged to feed this gel material into the nip of a pair of rollers 3, 4 of which the upper roller 3 is of steel and the lower roller 4 of rubber so as to accommodate variations in teh size of evenness of the particle layer.
~lso feeding into the nip of the rollers 3, 4 are two continuous webs of tissue paper, tc form carrier , ~, ;::
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, layers 5, 6 supplied from s~pply roll9 7, 8 via in-termedia-te ~eed rollers 9. In each case a water spray device 10 i9 provided which wets the tissue carrier webs 5 and 6 be*ore they reach the nip o~
rollers 3 and 4.
The wetted carrier layer9 5, 6 then receive the layer of particulate gel at the nip of the two rollers

3 and 4 and therea~ter feed forward as a composite sandwich ply through a heating chamber 11 which removes moisture fxom the tissue carriers and gel, round a cooling roller 12 and thence to a storage reel 13.
The heating chamber 11 is an enclosure consisting essentially of an open feedthrough system of rollers 14, radiant heaters 15, and forced extraction e~haus~ duct 16.
The material on the storage reel 13 is ~lit on a conventional slitting machine into a width to suit the tampon dimensions and the required num~er o~ layers o~
sandwich stock material.
Referring now to Figure 2, this shows the first part o~ the system ~or the production of tampons from the gel sandwich stock material ~ormed on the equipment described with re~erence to, and as shown in Figure 1.
In Figure 2 this sandwich stock material 18 may be used in one, two, three or four layers which may be formed using cutting, ~olding, and directional re-orientatlon s~stems as required. These methods are well known to those skilled in the paper handling art and for clarity - , ~ , , .

s ~ cZ.17 only the single layer sandwich 17, and the Putting knife 20 are shown in Figure 2, The discrete pieces 21 of sandwich material thus formed are fed by the conveyo~ 19 to the next stage.
At the next ~tage a web 220~ a non-woven fluid pervious outer cover material is fed from a supply reel 23 in the longitudinal feedin~ direction rollowed by the sandwich stock material 17.
The feed speed of the non-woven web 22 i9 just over twice the speed o~ feed o~ the stoc~ material 17. Thus, the discrete pieces 21 are picked up by the web 22 with a spacing between successive pieces which is slightly greater than the length o~ each piece.
A polished ~haped guide piece (not shown) then ~orces the web into a sleeve shape on a mandrel 25 with the two edges of the web 22 overlapping. Thsse webs are heat sealed or glued by a roller 24 as the web ~eeds onto the ma~drel 25.
Referring now to Figure 3, the mandrel which is a low ~ sur~ace friction bar having a hollow 26 at its further end, carries a series of spaced pieces of sandwich stock 21 surrounded by an overlying sleeve shaped layer of non-woven material 22. The material i9 carried along the mandrel by a pair of endless belt conveyors 27 which each carry spaoed rubber grippers 28 located to grip the web at the points where the pieces of sandwich stoc~ 21 locate.

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~ 2 ~ c~.174 1, The material is -~ed of~ the end of the mandrel to a position where a pair o~ cutter rollers 29 bring knife edges together to cut the end o~ the web 22. An air blast jet 30 is then aetuated, and thi~ ~orces the free end of the web back into the hollow 26 at the end o~
the mandrel (see Figure 4). The ~rippers 28 are continuously ~eeding the material on9 so that the ~olded ma~erial passes the cutter rollers. Then, when the position shown in Figure 3 i 9 again reached, the so-~ormed tampon (at the extreme right hand position of Figure 3) is severed.
The so-formed tampon is then fed to further machinery where the tampon i~ compressed to a tight cylindrical form, a string is tied to the end, and is inserted in a telescopic ¢ardboard applicatorO These can all be standard operations, well known in the art and in consequence have not been described.
Re~erence i9 now made to Figure 5 which diagrammatically shows a tampon in accordance with the invention, having a withdrawal cord 31. In the tampon shown, the sandwich i~ ~olded into two layers, and it will be seen that the absorbent gel material 32 is well protected, by virtue o~ two layers o~ material, one of tissue 5 or 6 and one o~ the non-woven outer 22. Moreover these two layers of material act as both a capillary path to the gel, and a temporary reservoir until the gel has absorbed the extant liquid. In this described example the gel is ~' .
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~ 2~ cz .174 shown as a continuou~ coat:ing between, and in practice bonded to, the internal surfaces of the two carrier layers. Two alternatives have also been found particularly satis~actory.
The first is whexe the gel coati~g i~ in the form of stripes as described in German Patent Application P 26 36 899.0; and the ~econd is where the gel is disposed within a discrete inner layer as a mixture with a wicking filler material in particular cellulose or other fibre~ such as textile of wood pulp fibres, or polyurethane or other suitable plastics foam. The cellulose fibres and gel material can be formed into the inner layer by being mixed dry and fed from the hopper 1 as with the gel coating, or can be formed from a wet slurry by a paper making method on the lines of the well-known Fourdrinier process.

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Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A hollow conical tampon for the absorption of body fluids comprising an absorbent inner material in the form of an annular sleeve enclosed within the inner and outer layers of an annular shaped bag of fluid previous material, said absorbent inner material being in the form of a sandwich com-prising a quantity of absorbent gel material held between two thin, foldable non-woven carrier layers at least one of which layers is of a fibrous material having capillarity and serving as a temporary reservoir to carry the fluid until it has been absorbed by the gel material.

2. A tampon according to claim 1 in which the gel material is bonded to both adjacent carrier layers.

3. A tampon according to claim 1 in which the gel material is incorporated in an inner layer which inner layer comprises a mixture of the gel material and a wicking filler material.