Patent Application
20070038192
The invention relates to a hygiene article, such as a sanitary napkin, a tampon or an incontinence pad, consisting of a textile fabric formed by a multiplicity of fibres.
The invention also relates to a process for producing a hygiene article.
Hygiene articles usually utilize fibres which possess high absorbency by virtue of their foundation material and their cross section. Viscose is frequently utilized as foundation material. The fibres are generally processed to form flexible, porous textile fabrics, usually fibrous nonwoven web fabrics, not by interweaving of warp and weft or by interlooping, but by interentanglement and/or cohesive and/or adhesive interbonding of textile fibres. This produces looser fabrics, which are very absorbent. Known fibres for making the fibrous nonwoven webs are manufactured fibres or filaments, usually of polypropylene, polyester or viscose, their coherency generally being due to their autoadhesion. Adhesively consolidated fibrous nonwoven webs are formed by interadhering the fibres with liquid binders or by melting or dissolving binder fibres admixed to the fibrous nonwoven web in the course of its production.
In cohesive consolidation, fibre surfaces are solubilized by. suitable chemicals and conjoined by pressure or welded together at elevated temperature.
The disadvantage with existing hygiene articles is that temperature elevations, for example in the event of high ambient temperatures or physical activities on the part of the person using the hygiene article, give rise to perspiration or sweating complete with the problems resulting therefrom.
It is an object of the present invention to provide a hygiene article of the kind mentioned at the beginning that offers a higher wear comfort, more particularly is capable of accommodating excess body heat and hence of reducing perspiration or sweating.
In accordance with the invention, this object is achieved when microcapsules having reversible heat-storing properties are included in at least a portion of the fibres or are applied via a coating with a binder atop at least a portion of the fibres or of the surface of the fabric, the microcapsules including materials in which a phase transition from solid to liquid, and vice versa, takes place in a temperature range from 15 to 40° C.
The invention's incorporation of fibres comprising microcapsules comprising phase transition materials provides distinctly improved wear comfort to the fabric. Excess body heat can be accommodated by the phase transition materials in the microcapsules whereby overheating of the body of the person wearing or using the hygiene article, and hence perspiration or sweating, can be distinctly reduced. The invention's fibres with microcapsules are able to smooth out temperature fluctuations of the body for a prolonged period. Dynamic temperature regulation is achieved in this way.
The hygiene article of the invention utilizes a law of nature. At a phase change temperature, in which material changes from solid to liquid or vice versa, the material absorbs and holds a large quantity of thermal energy at a constant temperature before changing to the next phase. Thus, the material can be used as an absorber, for example for a hygiene article, in which the microcapsules are integrated or otherwise arranged, before its temperature can rise. Conversely, it is likewise possible to use an appropriately preheated material as a barrier to cold, since, for a transition from liquid to solid, thermal energy must first be removed from the phase change material before its temperature can drop. However, the last is less interesting for hygiene articles.
The hygiene article of the invention can be produced in various ways.
One possible example is for fibres comprising the invention's microcapsules in which the phase transition materials are included to be produced separately and these fibres then to be combined with other fibres for processing to form a fibrous nonwoven web. It is also possible of course for the entire fibrous nonwoven web to be produced from the invention's fibres comprising microcapsules and phase transition materials.
Alternatively it is also possible for hitherto used “normal” fibres or yarns to be used, in which case these are then provided with a coating with a binder before their processing to form a textile fabric, for example a fibrous nonwoven web, in which case microcapsules with the phase transition materials of the invention are then dispersed or otherwise accommodated in the binder.
Instead of a coating of individual fibres, it is also possible for the textile fabric produced from the “standard” fibres correspondingly to be provided with a coating with a binder and, included in the binder, microcapsules comprising phase transition materials.
The coating may be effected for example with a liquid polymer binder, which is applied in a dipping or spraying operation. Of course, a printing, coating or spreading process is also possible.
The textile fabrics which, in accordance with the present invention, are provided with the microcapsules and the phase transition materials included in the microcapsules can then be further processed using known manufacturing sequences to form the desired end product in a conventional manner.
An illustrative embodiment of the invention will now be described in principle with reference to the drawing, where
The sanitary napkin presented in
The hygiene article 1 is provided with a multiplicity of microcapsules 3 incorporated in the textile fabric in the manner described hereinbelow.
Such microcapsules and phase transition materials as well as integration in fibres are already known in principle. See for example EP 0 306 202 B1 (=U.S. Pat. No. 4,756,958), the disclosure content of which is also fully part of the present invention. Examples of thermal transition materials useful in the interior of the microcapsules 3 are paraffinic, phase-changing hydrocarbonates or else plastically deformable crystalline materials.
Useful crystalline materials include for example 2,2-dimethyl-1,3-propanediol (DMP) and 2-hydrooxymethyl-2-methyl-1,3-propanediol (HMP). When such crystals absorb thermal energy, the molecular structure is temporarily modified without changing the phase of the material.
The foundation material for the fibre can be a synthetic polymer, for example polyester, nylon, acrylic or modacrylic or a cellulose fibre, for example viscose.
The size of the microcapsules 3 can be between 0.5 μm and 1000 μm, preferably between 2 and 30 μm.
The textile fabric 1 of
The coating process and its construction are already known in principle, which is why no further details will be provided here. See for example EP 0 611 330 B1 (=U.S. Pat. No. 5,366,801), which likewise forms part of the disclosure content of the present invention.
Instead of coating the textile fabric 1, it is also possible, as depicted in
Instead of a production of the hygiene article from a fibrous nonwoven web comprising a multiplicity of individual fibres 2, the hygiene article can also be produced from multicomponent fibres comprising microcapsules. The textile fabric 1 can be formed from multicomponent fibres as a fibre body, in which case at least a portion of the fibres includes microcapsules 3. This process is likewise already known in principle and shall for its disclosure content likewise form part of the content of the present invention. Reference is made to US 2003/0035951 A1.
It is similarly possible to produce the hygiene article from cellulosic fibres comprising microcapsules 3. WO 2005/017247 A2 supplies further details, which shall likewise form part of the disclosure content of the present invention. The advantage of cellulosic fibres is that they are able to take up appreciable amounts of moisture. However, conventional cellulosic fibres are disadvantageous in that they when wet, for example when wet with sweat, are unable to give off body heat to a sufficient degree, and therefore wear comfort suffers as a result. This is where the invention provides a remedy through integration of microcapsules 3 comprising phase transition materials in the fibres.
Fibres 2 comprising microcapsules 3 including phase transition materials can be partially mixed with other fibres, or else the fabric can consist of up to 100% of these fibres.
Since the inner ply or plies facing the wearer of the sanitary napkin is or are closest to the body, at least the inner ply 1d or the two innermost plies 1c and 1d are provided with fibres 2 comprising microcapsules 3. The innermost ply 1d or the two innermost plies 1c and 1d may each be fully formed of fibres 2 comprising microcapsules 3, or else if necessary only partially.
Viscose will be found to be particularly advantageous as a preferred material for at least the ply which is provided with the fibres 2 provided with microcapsules 3, or is formed of these.
It will be appreciated that other materials are also possible instead of viscose and similarly that it is also possible for a plurality of plies of the sanitary napkin to be formed of the fibres 2 provided with the microfibres 3. Similarly, the number of depicted four plies may of course be chosen according to the planned use.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 032 769.9 | Jul 2005 | DE | national |
