DE19949115A1 - Liquid distribution and storage system - Google Patents

Description

In many areas of daily needs (body hygiene, medicine, Food packaging) and in a wide range of technical areas Applications, in the agricultural sector (irrigation), in composite Structures and a. m. are used, among other things, to absorb the accumulated Liquids and pasty - viscous waste on preferably aqueous Base transport and absorption media used, both can be cellulosic (fluff pulp) or z. B. based highly absorbent organic polymers e.g. B. based on acrylate are built up.

In this application history, fluff pulp has emerged particularly for cost reasons. Its essentially bifunctional properties

• a) wettability, adsorption behavior and transport capacity for aqueous media, and
• b) absorption behavior and moisture retention under Pressure load

have, albeit imperfectly, especially in the areas Personal hygiene and incontinence make the display more functional Products.

These are also for the imperfection of the product solutions aforementioned bifunctional properties responsible because of Transporting the moisture only "works" as long as one Absorption of the same has not yet taken place or has occurred only insignificantly. Once the maximum absorption rate of the fluff pulp has been reached, it can a liquid transport no longer take place. Additional accruing Liquids are no longer controlled or absorbed and run beyond the saturated absorption medium and cause various problems in terms of comfort and Functional security.  

The attempts to cellulosic raw materials such. B. Fluff pulp through transportable and absorbable polymers based on synthetic z. B. Has to replace polyacrylate or others at least partially or completely shown limited success. The absence of a so-called The transport function consequently led to a Moisture absorption combined with the problems of so-called blocking, where the associated with the absorption process Volume increase especially for the superabsorbent Polymer (SAP) led to a moisture-impermeable gel.

Only the further development of these synthetic absorbers (SAP)

• a) moisture transportable and
• b) absorbent and at the same time capable of retaining moisture Systems among those typical for the application Printing conditions

led to improved products compared to the traditionally used Fluff pulp. Absorption behavior and especially retention under pressure conditions are at a higher level than Fluff pulp. The installation of transport-improving elements in the Molecular structure of SAP led to a drop in total Absorption capacity as well as retention capacity below Printing conditions compared to the original chemistry of SAP.

As a consequence, this has led to improved absorption systems in Mixtures between fluff pulp and SAP pass over fluff pulp alone managed and is state of the art today. But that's not really the case convincing solution has been found e.g. B. Personal hygiene products like this produce that periodically occurring larger amounts of excreted body fluid or feces so quickly absorbed be that leakage of the liquid or viscous masses in the area the diaper ends z. B. is prevented on the leg.

Numerous attempts to address these problems through appropriate construction of the To fix personal hygiene products u. a. with so-called Aqisitionlayers or distribution layers made with the aim of  Distribution of liquids over the entire surface BEFORE reaching to enable the absorption level. The results are both unsatisfactory in terms of efficiency as well as cost sustainability.

The main reasons for this are physical Shortcomings of the economically producible synthetic fiber Systems as well as the inadequate possibilities, the longitudinal axes of the Fibers in the composite according to the requirements of Align transport directions in three-dimensional space and the thereby statistically formed capillaries for the liquid transport to be able to use without loss.

The present invention is based on the task, To create liquid transport systems that are not themselves Have absorption behavior and due to their physical and chemical construction as long as liquids in predetermined Can transport directions, like at the end of the transport chain sufficient absorption capacity is available. It should only play a subordinate role, whether for absorption fluff pulp, superabsorbent polymers with or without self-transport capabilities for Liquids, other absorption media or mixtures thereof be used.

In the attempts to implement the task, it has now surprisingly been found that not only between parallelized fibers but also across the open cross sections formed between two mutually spaced surfaces, e.g. B. foils can be transported,

• - If the film surface of the liquids to be transported is wettable, or the surface tension of at least one of the two foils is lower than that of the transported Liquid,
• - The distances between the two foils correspond to transporting viscosities,
• - The distance between the foils is essentially constant or
• - Is kept constant via spacers, and  
• - If an absorption medium is effective at the end of the transport route or is in direct contact with the transport system stands
• - And that with the correct procedure or with application softer and very thin foils such "film composites" in no way disturbing for the end consumer, but rather to the highest degree Improving comfort by the fact that the installed Absorption capacity used faster and in the entire area becomes an increased dryness with improved Well-being of the wearer. The "leakage" of a diaper Inconsistency of fluid intake / time unit with Transport and absorption behavior e.g. B. can be targeted can be prevented, provided that absorption capacity in the areas further away to a sufficient extent is available.

It was also surprisingly found that this system was not only works when the exit point for the liquids is out the transport system is lower than the point of entry and that The weight of the liquid favors transport.

Also in the opposite direction, that is from bottom to top, takes place under practical conditions when using baby diapers, Sanitary napkins, incontinence products, meat and / or Food packaging and similar application mechanisms Transport of aqueous to low-viscosity body excretions or Tissue secretions take place. Pulsation effects through the use of the Body weight caused by the wearer or user of such Products also have a positive effect.

In the element described as transport system I, between two 5 micron thick PE films 3 mm thick monofilaments foamed PE arranged and frictionally in contact with it brought. The arrangement of the transport elements in a diaper corresponded essentially to the attached schematic representation of the Functional processes.

For the element described as transport system II, the for the "capillary cross section" necessary for the liquid transport through and form-fitting assembly of two 10 micron thicker and modified PP films and by "pleating" one of the two Films reached.  

For transport system III, starting with transport system II A modification of the open cross section on the entrance side made on the output side. So here is z. B. the ratio of open cross-section on the input side: 2: 1 on the output side. This procedure accelerates the Liquid transport within the capillary. In addition, a Filtration effect within the capillary can be used in which coarser components are separated from the aqueous phase can do that depending on the particle size of the coarse constituents over the length of the transport channel with increasing narrowing of the Selective filtration takes place cross-section.

In a further special embodiment IV, the for the Liquid transport responsible "sewers" with inclusion for the outer seal on the one hand and for the Water vapor exchange on the other hand responsible film part of the so-called "backsheets" and a further spaced film educated.

Furthermore, it has been confirmed that all or some of those on the canal network involved channels on the side facing the absorption medium in freely selectable distances can be provided with small holes or pores can be used to transport liquids on the one hand and on the other hand Use absorption capacities across large areas to be able to.

While embodiments I-III serve both as a transport system ON the absorption element, i.e. on the body facing Page AND alternatively under the absorption element, i.e. on the Body facing side arranged can be used finds the use of embodiment IV consequently only on the Body facing away from the absorbent element instead.

In the latter form of application, it has been found to be advantageous that the absorption element - the so-called "core" - in the immediate Area of the body openings responsible for excretion remains spared and between the outer boundary of the Body hygiene products on the one hand and the "exiting" part of the body on the other hand, a cavity is formed, at the ends (Limits) the liquid transport systems protrude into them and have free access to the resulting excretions and to them Can perform their function unhindered.

In the described for the embodiments I-III Application characteristics are not such recesses in the core  imperative, but here too there are gaps advantageous transport properties, because in this way the fastest possible transport to higher or further from the Elimination zone distant absorption areas is reached.

According to the schematic representation, depending on the size of the Personal hygiene products the transport systems also in multiple Arrangement along and / or across the absorption body in the Construction of the absorption medium can be organized in order to an optimal utilization of the suction capacities on the one hand and one safe "Rewet" function to come in the entire area of the pad. In this case, the entry channels should be those for liquid transport responsible transport systems advantageously on the Body-facing side of the absorption pad may be arranged.

In a special embodiment of a multi-channel transport and distribution system as shown in the transport system I-IV can the second channel in the order across the width of the "Pads" are designed as air cushions. These channels are in the beginning and sealed airtight at the end of the capillary after using it beforehand an air pressure greater than 0.1 mbar and less than 1.0 bar were. In this way, the spacers can be very thin, soft and elastic and comfortable for the user. The resulting cushion effect has a particularly positive effect the exchange of volume-forming absorbents native and synthetic type.

All embodiments can alternatively be applied so that the described channel structures on one side as described Absorb liquids and also as described from Transport the distribution site away into a "foil bag" that only one or more inputs but no output and the preferably enriched with superabsorbent polymers or but is filled and with this available suction capacity the questionable Liquids bind in a form known per se. For this you can SAP types are preferably used which Absorption abilities but no or only limited Have transport capabilities for liquids. But also known absorbents on a native basis such. B. Fluff pulp, clay etc. can be used for this.

Polyolefins are preferably used as raw materials for the films described such as PE, PP, their derivatives and copolymers and / or block  Copolymers and the usual polymers to improve the Softness and stretching behavior at low Forces such as B. EVA, EMA, EBA, SBS, SEBS, other Butadiene - derivatives, waxes, paraffin oils can be used. But also PB, acrylic acid derivatives, polyamides and their homologues, polyesters and their homologues, polyurethanes and their descendants, polystyrenes, chemically modified celluloses, PVC and PVA all alone or Mixtures of these can be used to make the films become.

The surfaces of the Films or at least parts of the films or the connection points of the Foils or those used to produce an adhesive connection Adhesives have surface tensions of <40 dynes / sec. preferably however <24 dynes / sec. or surface tensions, at least 1 dyne / cm below the expected surface tension of the the respective liquids (e.g. urine, blood, wound secretions, faeces). These surface tensions can alternatively be known per se Way about electro-physical discharge processes, about surface tension reducing additives such. B. antistatic or suitable surfactants or via the addition of hydrofiles or polar Polymers such as acrylic derivatives, vinyl derivatives, EVA, Polyester and its copolymers, polyamides and their copolymers and similar can be set.

The dimensions or the opening cross-sections of the channel systems used for the transport essentially depend on the offered viscosities of the body secretions. The rule applies that the higher viscosity always requires the larger opening cross-section in order to be able to transport effectively. Opening cross sections from 0.001 mm × 0.001 mm (1 micrometer ² ) to 100 mm ² have proven to be functional. The geometric shape of the opening cross section is not tied to any particular rule, so that all conceivable geometries are possible. The film thicknesses used are between 0.004 mm and 1,000 mm, preferably between 0.01 mm and 0.04 mm. But also tightly extruded, straw-shaped and connected "hoses" with analog wall thicknesses can be used.

The course of the channel systems can be linear and straight take place as well as in the most diverse curve formations starting from a preferred point of fluid accumulation Transport and distribution of the same to the greatest possible To allow absorption area. There can also be several identical ones  or non-identical transport systems one above the other and / or be arranged one behind the other.

The penetration time according to the Courtray Consulting Labservice test method for a 1st set of e.g. B. 80 ml of a synthetic urine in one Absorbent body consisting of z. B. 60% commercial fluff pulps and 40% of a commercially available superabsorbent under simultaneous Application of the channel systems described above (exemplary embodiment I.) was up to 40% lower compared to a standard one Product structure with a so-called distribution layer.

The second amount of a further 80 ml of synthetic urine became up to 50% faster and the further 3rd amount of 80 ml. Synth. Urine was up to 70% faster compared to the commercial product structure from the Seizure area transported to the target area and absorbed. At the 3rd liquid addition to the product with commercially available The distribution system installed there was already like this heavily overwhelmed that about half of the amount of liquid no longer controlled and absorbed and on the sides of the DUT ran out, so a so-called "leakage" arose.

The advantages of using the described distribution systems are diverse and are obvious.

• 1. The reduction of transporting and / or absorbing native or synthetic polymers over the possible 100 % use of absorption capacity.
• 2. Simplifying the structure of personal hygiene products and the waiver of costly acquisition or distribution Traditional design systems.
• 3. Use of cheaper synthetic absorbers without Transport function and with increased absorption capacity.
• 4. More environmentally friendly product design
• 5. Dramatic improvement of the functions comfort, Wear safety and the psychological stress of the end user in use.
• 6. Cost reduction.

Claims (12)

1. Liquid transport, liquid distribution and liquid absorption system for aqueous to medium-viscosity liquids, in which the liquids in the area of the liquid seizure are taken up immediately after the seizure by a channeling capillary system and transported to absorption areas further away from the point of elimination and distributed on the way there as well as in the end area are used with the purpose of being able to optimally use the entire installed absorption capacity of native and synthetic absorbents, characterized in that the channeling capillary system consists of at least one channel, which is formed from at least two spaced surfaces and associated spacers and in the open Cross-section the liquids are guided monodirectionally and / or multidirectionally from the supply location into areas of higher demand (absorption) and are absorbed here. 2. Product according to claim 1, in which the channeling capillary system consists of foils with a thickness of 0.004 mm and has an opening cross section of the formed capillary of 0.001 mm ² . 3. Product according to claim 1, wherein the channeling capillary system consists of foils with a thickness of 1.0 mm and has an opening cross section of the formed capillary of 100 mm ² . 4. Product according to claim 1, wherein the channeling capillary system consists of foils with thicknesses of 0.004 mm and 1.0 mm and has an opening cross section of the capillary formed of 0.001 mm ² to 100 mm ² . 5. Product according to claims 1-4 in which the raw material base of the films used in essentially from PE, PP, PB, their derivatives or copolymers and / or block Copolymers exist as well as the usual polymers to improve the softness and the expansion behavior with low force such. B. EVA, EMA, EBA, SBS, SEBS, other butadiene derivatives as well as waxes and Processing aids are included in the usual way. 6. Product according to claim 1-5. where some or all of the film surfaces are wettable for liquids with surface tensions of <24 dynes / cm. 7. Product according to claims 1-6. Where the surface tensions are physical discharge processes, about use surface tension reducing additives in the film formulation (e.g. Antistatic agents), on the surface treatment of the films with suitable hydrofiles or polar surfactants or by adding hydrofiles or polar Polymers such as B. acrylic acid derivatives, vinyl derivatives, EVA, polyester and its Copolymers, polyamides and their copolymers can be produced or adjusted. 8. Product according to claim 1-6. In which only parts of the composite Capillary system show hydrofile or polar character or hydrofile behavior,  e.g. B. that only one of the surfaces involved in the capillary system or in the Connections applied adhesive hydrofile are formed. 9. Product according to claims 1-8. With the entrance cross section of the capillary system is up to a factor of 20 larger than the initial cross-section. 10. Product according to claims 1-9. In the at least one of the capillary systems limiting foils also part of the outer shell of a Personal hygiene product is. 11. Product according to claims 1-10. In which the capillary system on the output side into a sack-shaped construction, which in turn with absorbent media is enriched or filled and thus quasi an absorption in a dead end practiced. 12. The product of claims 1-11, wherein the position of every 2nd to 10th channel is through closed on both sides, filled with air pressures from 0.1 mbar to 2.0 bar and thereby equipped as air cushion elements, which in turn for the Ensure that the foil surfaces are spaced apart.