IE911096A1

IE911096A1 - Tampon and manufacture thereof

Info

Publication number: IE911096A1
Application number: IE109691A
Authority: IE
Original assignee: Hoechst Ag
Priority date: 1990-04-03
Filing date: 1991-04-03
Publication date: 1991-10-09
Also published as: DE4010701A1; EP0450489A1; AU7399791A; AU637473B2; JPH04224748A; PT97228A

Abstract

A tampon made of continuous filaments based on a chemical fibre cable having a water retention value of at least 1000% by weight and substantially comprising continuous filaments aligned parallel to the longitudinal axis and having free filament ends virtually only on the two limiting cross-sectional areas.

Description

HOECHST AKTIENGESELLSCHAFT HOE 90/F 101 Dr.AC/fe Description Tampon and manufacture thereof The present invention relates to a tampon made of con5 tinuous filaments and to a process for manufacturing it.

Tampons are customarily made of webs, in particular card webs. They generally comprise cellulosic fibers.

US-A-4,627,849 discloses tampons whose defining feature is the imposition of a so-called microwaviness. This is to be understood as meaning an arrangement of crimped individual filaments in which the curved portions of a plurality of filaments are grouped together so as to confer waviness on the fiber mats used as a whole. From Figures 7 to 9 of this patent it is also possible to discern a method of manufacture wherein a fiber mat is rolled up, starting from the middle, and then pressed to form the end product. This embodiment has at its surface a multiplicity of free filament ends. Such free filament ends can lead to skin irritation and allergic reactions and therefore are undesirable on the surface of a tampon.

The patent in question also proposes the use of continuous fiber tows (hereinafter referred to as tows), but this possibility is not further embodied therein.

It has now been found that tampons can be manufactured from tows in a simple manner. This process does away with the textile pretreatment steps which are necessary with the use of card webs. Furthermore, the product obtained has an appreciably reduced level of free filament ends at its surface.

The present invention relates to a tampon as defined in claim 1.

The fiber material used for the purposes of the present - 2 invention must have a water-holding capacity (as defined in German Standard Specification DIN 61640) of at least 1000 % by weight, i.e. it must at least be able to hold an amount of water which corresponds to at least ten times its own weight. Customarily, the water-holding capacity is 1000-2000 % by weight, but preferably it is at least 1500 % by weight.

The fiber material can be cellulose, preferably unmodified cellulose. Examples thereof are cellulose spun by the direct solution process, for example from N-methylmorpholine N-oxide as solvent, and regenerated cellulose, such as cuprammonium rayon or in particular viscose rayon.

The tow used has a linear density of about 30 to 180 ktex, in particular of about 70 to 120 ktex. The choice of the tow linear density depends essentially on the desired dimensions of the end product.

The linear density of the individual filaments of the tow to be used is customarily between about 1 and 10 dtex, in particular of about 2 to 5 dtex. The choice of this parameter is limited at the upper end by the necessary mechanical strength of the tampon, while the lower limit is chiefly determined by the economics of the fibermaking process .

The tow to be used must be crimped in order to confer sufficient strength on the end product. It is possible to employ any kind of customary crimping, such as gear crimping and in particular stuffer box crimping. Especially in the case of viscose filaments the crimping due to the viscose process can be sufficient without further mechanical treatment.

Essential features of the tampon of the present invention are the construction from continuous filaments and the essentially parallel arrangement of these filaments with the longitudinal axis of the tampon. This makes it possible that free filament ends appear virtually only at - 3 the bounding cross-sectional surfaces of the cylinder and that the cylinder surface which later comes into contact with the skin has virtually no such free filament ends.

The tampon of the present invention can be manufactured 5 directly from the tow material or it can be additionally provided with a wrapping fleece.

Such wrapping fleeces are known per se. They comprise for example ultralightweight fleeces based on polyester/ polyethylene bicomponent fibers. The basis weight of such wrapping fleeces is preferably less than or equal to 15 g/m2, particularly preferably about 10 g/m2.

The tampon of the present invention can be provided with a recovery string. This string can be introduced either during the continuous manufacturing process or only after the shaped tow bundle has been cut to the desired size.

The recovery string can be a folded or single yarn made of natural and/or synthetic fibres. The folded or single yarn used in particular is made of a thermoplastic polymer which, after introduction into the tampon, can be adhered to the surrounding filaments, for example by heating to above the softening point of the thermoplastic polymer. The recovery string is preferably attached in the longitudinal axis of the tampon. The tampon of the present invention can be manufactured by a method similar to that used in the manufacture of cigarette filters. The function and the resulting configurations of tampons and such filters are not the same. Tampons must be configured in such a way that their surface ensures a very large and uniform uptake of liquid, while the surface of cigarette filters must represent a very gas-tight seal to ensure functioning of such a filter. Thus, it was not obvious to use such a process for manufacturing tampons.

The process of the present invention is defined by the measures specified in claim 7. - 4 The fanning out of the tow may be effected by any suitable process known per se. In general, an incoming tow is opened mechanically and/or by jets of fluid. Examples of such processes may be found in US-A-3,156,016 and in DE-A-1,435,417.

The fanning out may if necessary be aided by electrostatic charging.

The fanning out has the purpose inter alia of uniformizing the arrangement of the individual filaments.

After this step, the fanned-out tow is introduced into a guide element for the purpose of compacting the tow while preserving the essentially parallel arrangement of the individual filaments. The guide element customarily comprises a funnel-shaped apparatus into which the fanned-out tow is introduced at the wide end and in the narrow part of which the tow is compacted to the desired linear density.

Preferably, the fanned-out tow is introduced into the funnel-shaped apparatus at a higher speed than it is removed therefrom. The speed difference is converted into energy of compression and serves to compact the tow in the narrow part of the apparatus.

During the process of compaction it is possible to introduce a recovery string, preferably by continuously guiding a thermoplastic thread into the fanned-out tow, so that on compaction this thread extends along the longitudinal axis of the tampon.

The compacted tow is then pressed by applying a pressure perpendicularly to the cylinder surface. A suitable apparatus for this purpose is described for example in Figures 4, 4a and 4b of US-A-4,627,849.

Thereafter or prior to the pressing, the compacted tow is cut to the desired size. Then any recovery string which has been introduced is pulled part way out of the tampon, - 5 possibly being stretched in the process, and is then adhered to the fiber material. This is preferably effected by heating a thermoplastic material to above its softening point.

A further embodiment of the process of the present invention comprises the wrapping of the compacted tow in a wrapping fleece. This may be effected with a conventional apparatus, for example as shown in Figure 3 of US-A-4,627,849. However, the wrapping can also be effec10 ted batchwise, for example after the compacted tow has been cut to size. Preferably, the wrapping takes place continuously, as defined in claim 9.

The tampons of the present invention can be used for many purposes, for example for medical purposes or in par15 ticular as catamenial devices. They are noteworthy for high absorbency and for particularly good compatibility. More particularly, they are simple and economical to manufacture.

Claims

1. HOE 90/F 101 What is claimed is:

1. A tampon made of continuous filaments consisting essentially of a tow of crimped man-made fibers 5 having a water-holding capacity of at least 1000 % by weight and a linear density of about 30-180 ktex with the individual filaments of this tow having a linear density of about 1 to 10 dtex, the tampon consisting essentially of continuous filaments in a 10 parallel arrangement with the longitudinal axis and having free filament ends virtually only at the two bounding cross-sectional surfaces.

2. The tampon of claim 1, wherein the man-made fibers are cellulosic fibers.

3. The tampon of claim 2, wherein the cellulosic fibers are viscose fibers.

4. The tampon of any one of claims 1 to 3, wherein the individual filaments have a linear density of about 2 to 5 dtex. 20 5. The tampon of any one of claims 1 to 4, comprising a core of continuous filaments arranged essentially parallel to the longitudinal axis, said core having been provided with a wrapping fleece. 6. The tampon of any one of claims 1 to 5, provided 25 with a recovery string made of a thermoplastic material which has been introduced into the tampon in the longitudinal axis thereof and adhered to the surrounding filaments. 7. A process for manufacturing a tampon as claimed in 30 claim 1 starting from a tow of crimped man-made fibers possessing a water-holding capacity of at - 7 least 1000 % by weight and having a linear density of about 30-180 ktex with a filament linear density of about 1-10 dtex, comprising the steps of: i) fanning out the tow in a suitable apparatus for

5. Uniformizing the arrangement of the individual filaments, ii) introducing the fanned-out tow into a guide element which has a cross-sectional area much reduced compared with the fanned-out tow in 10 order to compact the tow while preserving the essentially parallel arrangement of the individual filaments, iii) cutting the compacted tow into cylindrical pieces of a length appropriate to the desired 15 purpose, and iv) pressing in order to confer the desired mechanical strength and the desired thickness on the tampon, wherein steps iii) and iv) may also be carried out in reverse order. 20 8. The process of claim 7, wherein prior to step ii) a thermoplastic thread is introduced into the fannedout tow in such a way that in step iii) it extends in the longitudinal axis of the compacted cylinder.

6. 9. The process of either of claims 7 and 8, wherein the 25 compacted cylinder of step ii) is provided with a wrapping fleece by continuously feeding a length of this wrapping fleece onto the compacted cylinder and laying it around said cylinder with a suitable apparatus. 30 10. The process of any one of claims 7 to 10, wherein the guide element of step ii) is funnel-shaped and the fanned-out tow is introduced into the funnel at 11. 11. 12. 12. 13. 13. a higher speed than that with which it is pulled out of the narrow part of the funnel. A tampon according to claim 1, substantially as hereinbefore described. A process according to claim 7, substantially as hereinbefore described. A tampon as claimed in claim 1, whenever manufactured by a process claimed in a preceding claim.