LIQUID DETECTION ORDER

Description

[0001] The invention relates to an arrangement for liquid detection in disposable hygiene products. Disposable hygiene products for babies and adults are commonly used, particularly in the form of diapers. Conventional disposable hygiene products of this type have a flat, longitudinally extended absorbent core that passes through the wearer's crotch when the disposable hygiene product is put on. The absorbent core often comprises superabsorbent material.

[0002] The absorbent core is mounted on an assembly comprising a polyolefin backsheet film. The assembly is designed to have a textile-like appearance. Preferably, the backsheet film is bonded to a nonwoven layer for this purpose. The assembly supports the absorbent core and seals it to the outside.

[0003] Under the heading "intelligent" disposable hygiene products, there is increasing demand for products that are able to detect their usage status.

[0004] Babies or people with dementia cannot assess the condition of disposable hygiene products themselves or communicate their needs accordingly. Checking by caregivers is time-consuming.

[0005] Smart disposable hygiene products offer a solution, automatically indicating when a change is needed. This improves quality of life and reduces the workload for caregivers. Furthermore, smart diapers contribute to environmental protection, as the disposable hygiene product's potential is fully utilized before disposal.

[0006] Against this background, various approaches to intelligent disposable hygiene products are known from the state of the art.

[0007] US Patent 6 200 250 B1 relates to a smart diaper in which capacitive electrodes are placed on a carrier film and a liquid-absorbing layer. The electrodes can be rectangular and connected in series or designed as threads. The electrodes can be glued or sewn into the diaper.

[0008] According to US 8 978 452 B2 and WO 2013 / 022742 A1, liquid sensors with a passive resonant circuit are proposed for a foil section in which the applied structures can be partially dissolved by a liquid.

[0009] In US Patent 8 978 452 B2, the condition of a hygiene product detected by a reader can subsequently be wirelessly transmitted to other devices via known data communication connections such as WLAN and Bluetooth.

[0010] German patent DE 10 2017 125 323 A1 describes a foil section with two conductive traces forming a passive resonant circuit. A reader and transmitter is connected to the conductive traces. One conductive trace is designed as a capacitor plate, and the other as an inductor. The conductive traces are applied to a carrier film, which in turn is mounted on a foil label. The foil label is enclosed in a PE film and affixed to the back of a hygiene product. This requires an additional step in the application process, resulting in a significant increase in the product's volume. This additional volume can negatively impact the product's comfort. Furthermore, the foil label itself is extremely complex in its design and manufacturing.

[0011] EP 2 654 646 B1 describes an absorbent article comprising a conductive and an open conductor loop. A liquid absorbed by an absorbent core measurably changes the impedance of the conductor loops. This works by orienting the conductor loops such that the current creates a short circuit on an outer leg of the second conductor loop.

[0012] EP 3 451 988 B1 and EP 3 760 104 A1 describe a liquid-impermeable substrate with a non-conductive insulating layer on which at least one channel for a sensor track is arranged. Preferably, sensor tracks are arranged in a colored reinforcing layer in the form of a patch, which, together with a data processing module, form a left and a right circuit for detecting moisture events.

[0013] According to EP 3 143 974 B1, a transmitter-receiver arrangement for monitoring the absorption layer can be detachably coupled to disposable hygiene products. This arrangement can then be used multiple times on disposable hygiene products. This allows future developments to focus on providing an affordable disposable hygiene product.

[0014] Electrodes and conductive tracks are complex and expensive. Disposable hygiene products are subject to price pressure and high environmental standards, as they are disposed of immediately after a single use. Furthermore, ease of use is also a key objective.

[0015] The described inventions usually consist of several layers with different properties that must be bonded together. This results in thick and heavy disposable hygiene products. This promotes the formation of pressure points and skin irritations for those wearing diapers, leading to an uncomfortable wearing experience. Furthermore, intelligent disposable hygiene products should be in no way inferior to conventional ones in terms of their tactile properties.

[0016] The object of the invention is to provide a simple and compact device for liquid detection. The device should be liquid-tight, meet the required mechanical properties, and ensure comfortable wear. Furthermore, the device should have a pleasing tactile feel. The aim is to provide a device that is as quiet as possible and possesses softness and flexibility. In addition, the device should provide conductive elements necessary for reliable liquid detection and yet be inexpensive to manufacture. The device should improve the quality of disposable hygiene products and meet the requirements of their production in modern processes.

[0017] This problem is solved according to the invention by an arrangement for liquid detection, according to the dependent main claim. Preferred embodiments can be found in the dependent claims, the description, and the examples.

[0018] According to the invention, the arrangement comprises a backsheet film with a conductive print, wherein the basis weight of the conductive print is less than 3 g / m², wherein the backsheet film is non-breathable and has a water vapor permeability of less than 500 g / m² in 24 h according to ASTM D6701-01, wherein the basis weight of the non-breathable backsheet film is less than 10 g / m², or the backsheet film is breathable and has a water vapor permeability of more than 500 g / m² in 24 h according to ASTM D6701-01, wherein the basis weight of the breathable backsheet film is less than 20 g / m².

[0019] According to the invention, the liquid detection arrangement comprises a backsheet film with a conductive imprint having an area-specific resistance of less than 10 kΩ. In a particularly advantageous embodiment of the invention, the area-specific resistance of the conductive imprint is less than 6 kΩ, preferably less than 4 kΩ, and more particularly less than 1 kΩ.

[0020] In an advantageous embodiment of the invention, the basis weight of the conductive print is less than 3 g / m², preferably less than 2 g / m², preferably less than 1 g / m², and in particular less than 0.5 g / m². For example, if a wet application of 2 * 3.5 g of conductive medium per m² is carried out with a coverage of 11% and a solids content of the conductive medium of 35%, the basis weight of the dry conductive print is 7 g / m² * 0.11 * 0.35 = 0.2695 g / m².

[0021] The area-specific resistance is configured by the amount of conductive ink applied, the thickness of the print, and the type of treatment. The area-specific resistance is at its lowest value immediately after printing. Changes in this resistance depend crucially on the properties, particularly the stiffness combined with elasticity, of the backsheet film. Only the backsheet film according to the invention, which is designed to be particularly stiff yet elastic, ensures that the printed area-specific resistance remains as low as possible even during further processing. The use of specific polyolefinic backsheet films ensures that the conductive traces of the print are not damaged during subsequent processing steps, for example, by cracking.

[0022] The area-specific resistance of the print can be measured with a multimeter using two measuring probes.

[0023] The surface resistivity of a printed surface can be determined using the four-point method or as a non-contact measurement with a special eddy current tester. Often, calculations are performed based on a known geometry. In the four-point method, the influence of contact resistance on the measurement is eliminated by generating a current flow between two contact points while measuring the voltage drop across two other contact points. In non-contact eddy current coating resistance measurement, an alternating electromagnetic field is generated in the material, and the measuring sensor evaluates the opposing field of this field.

[0024] The specific surface resistance R□ describes the electrical resistance of an electrically conductive layer of such small thickness that it is only traversed by electric current parallel to the layer, i.e. the current enters at one end face and exits at the opposite end face.

[0025] Preferably, the area-specific resistance is R □ a backsheet film measured on a printed strip of conductive print. For example, the strip has a length of 30 cm and a width of 6 mm, which in this case corresponds to 50 □, where a measured resistance of, for example, 60 kΩ would result in an area-specific resistance of 1.2 kΩ / □.

[0026] To better distinguish it from electrical resistance with the unit Ω, the specific surface resistance is used. R□ therefore often given in the unit Ω / □. However, such an indexing of physical units is not provided for in the standards DIN 1301 and ISO 31, which is why the unit Ω for the specific surface resistance is used in the claims. R □ is listed.

[0027] The imprint can be designed as a print pattern particularly suitable for liquid detection. In its simplest form, the print pattern is a stripe. Alternatively, it can consist of several stripes extending across the arrangement. Furthermore, the print motif can also be spiral, triangular, rectangular, and / or in a completely random geometric pattern. In one variant, the conductive traces are arranged in a checkerboard pattern.

[0028] The printing inks used for conductive printing are preferably low-viscosity inks, meaning they are almost as thin as water. In principle, aqueous, UV-curable, and solvent-based ink systems are suitable. These inks can be specifically adapted to the respective printing process and are therefore individually tailored to each printing press.

[0029] Conductive printing inks can be dried or cured, in particular, by heat and / or UV light. Conductive printing inks typically contain particles of conductive materials, such as graphite, copper, or silver, which may be in flake or powder form.

[0030] Within the scope of the invention, a conductive printing ink based on graphite is preferably used. Preferably, the conductive print is based on a carbon-based ink and / or a conductive, polymer-based ink. The carbon-based ink preferably comprises a conductive compound consisting of graphene, graphite, carbon nanotubes, and mixtures thereof. A conductive polymer-based ink preferably comprises a conductive compound consisting of polyacetylene, polypyrrole, polyaniline, and their copolymers.In particular, the conductive tin can consist of polypyrroles (PPY), polyanilines (PANI), polythiophenes (PT), polyphenylene sulfide (PPS), polyphenylenes (PPP), polyacetylenes (PAC), polyphenylene vinylenes (PPV), poly(3,4-ethylenedioxythiophene) (PEDOT) and mixtures thereof, with the conductive polymer-based tin best comprising a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).

[0031] Preferably, the conductive print is applied using a flexographic printing process, whereby all common printing processes are in principle suitable for this purpose and are expressly included in the invention.

[0032] Advantageously, the conductive print on the backsheet film shows no abrasion according to the ink rub-off test. Therefore, regardless of the print's orientation, transfer of the print to the wearer's skin is impossible when wearing the hygiene product.

[0033] In the ink rub-off test, a test arm with a fabric-like material is placed on the printed backsheet film. The table beneath the backsheet film then swings back and forth 15 times. The ink transfer to the fabric-like material is then evaluated, with three evaluation categories: pass (no ink rub-off), pass (with slight ink rub-off), and fail.

[0034] The arrangement according to the invention has a specific combination of features not known in conventional liquid detection arrangements according to the prior art. This specific combination of features makes it possible to use even thin and particularly simple arrangements that have a conductive imprint.

[0035] The arrangement according to the invention exhibits significantly better mechanical properties compared to conventional arrangements for smart diapers, is particularly soft and gentle, and manages entirely without complicated electrical circuits and their complex structures. The arrangement according to the invention is free of wires, electrical conductors, resistor circuits, and their insulating additional layers.

[0036] The arrangement according to the invention is particularly thin and at the same time rigid, so that the print is not damaged during processing in modern diaper converters. Furthermore, the arrangement according to the invention reliably ensures waterproofing despite its simple construction consisting of a backsheet film, a conductive print, and a nonwoven fabric.

[0037] In one embodiment of the invention, the arrangement comprises a nonwoven layer. The term "nonwoven" refers to a fabric that can be produced from continuous filaments and / or discontinuous fibers without weaving or knitting by processes such as spunbonding, carding, or meltblowing. The nonwoven fabric can comprise one or more layers, each layer containing either continuous filaments or discontinuous fibers. The nonwoven fabric can also comprise bicomponent fibers, which may have fiber structures such as sheath / core or side-by-side.

[0038] Preferably, the nonwoven layer consists of a polyolefinic nonwoven, in particular a thermobonded spunbond nonwoven. A polypropylene-based nonwoven is particularly suitable. The nonwoven layer preferably has a specific gravity of more than 6 g / m², preferably more than 8 g / m², in particular more than 10 g / m², and / or less than 20 g / m², preferably less than 18 g / m², in particular less than 16 g / m².

[0039] Connection areas are arranged between the nonwoven layer and the backsheet film. Advantageously, these connection areas are formed as a form-fitting composite of the nonwoven layer and the solidified material of the backsheet film. This is achieved by heating the thermoplastic polymer material of the backsheet film above its crystallite melting point in a process for manufacturing an assembly consisting of a backsheet film and a nonwoven layer, and then passing it, together with the nonwoven layer, through a cooled roller gap.

[0040] In a particularly advantageous embodiment of the invention, the conductive print is arranged on the side of the backsheet film where the nonwoven layer is bonded by thermal lamination. This is only possible because the backsheet film is particularly rigid, preventing the conductive print from tearing during further processing.

[0041] It proves particularly advantageous to apply the print directly to the backsheet film. This eliminates the need for an adhesion promoter, thus removing an additional process step. Furthermore, direct printing allows for a particularly thin design. No additional elements, such as those for liquid detection, are required. This is especially beneficial because it avoids potential sources of error associated with adding extra elements and performing further steps like unwinding the film web and applying the elements.

[0042] The arrangement is preferably manufactured in a process in which a specific composition is first extruded into a film web, preferably by blown film extrusion, and then cooled for further processing. The film web is then stretched in the machine direction and / or transversely to the machine direction. According to the invention, the conductive print is applied in an inline process. In this inline process, the film web does not need to be wound up and retrieved again before being bonded to a nonwoven layer. The application of the nonwoven layer is carried out "inline" and thus preferably immediately after the application of the conductive print in a single process. At the end of the process, the nonwoven can be mobilized. This is preferably done by means of ring rolling. This enhances the soft feel of the arrangement.

[0043] Ideally, the print is positioned between the backsheet film and the nonwoven layer. The inline process according to the invention allows a positive-locking bond to be formed between the backsheet film and the nonwoven without negatively affecting the conductivity of the print.

[0044] The method (not claimed) is particularly advantageous because the finished arrangement can be rolled onto webs without having to first roll up the film web separately after applying the conductive print, whereby the latter could be damaged by renewed stress and its conductivity reduced.

[0045] The backsheet film preferably comprises thermoplastic components, and it proves particularly advantageous if the polymer materials of the backsheet film and the nonwoven layer are matched to each other in such a way that, on the one hand, the crystallite melting points are sufficiently far apart and, on the other hand, the materials are compatible with each other to such an extent that a connection is made possible.

[0046] The difference in the crystallite melting temperature of the low-melting component of the backsheet film should be at least about 5 °C, preferably at least about 10 °C and in particular at least about 20 °C below the melting temperature of the nonwoven fabric or below the melting temperature of the high-melting component of the nonwoven fabric.

[0047] According to the invention, the backsheet film preferably comprises at least one low-melting polymer component and at least one high-melting polymer component.

[0048] The total amount of low-melting polymer component is preferably 90 to 30 wt.%, in particular 80 to 40 wt.%, most preferably 70 to 50 wt.%, the total amount of high-melting polymer component is preferably 10 to 70 wt.%, in particular 20 to 60 wt.%, most preferably 30 to 50 wt.%, each based on 100 wt.% low-melting and high-melting polymer component.

[0049] In one embodiment, the backsheet film contains at least one polyethylene as a low-melting polymer component and at least one polypropylene as a high-melting polymer component.

[0050] In one variant, the low-melting polymer component contains or consists of ethylene polymers, whereby both ethylene homopolymers and ethylene copolymers with ethylene as the main monomer, as well as blends of ethylene homopolymers and ethylene copolymers, are suitable. Suitable ethylene homopolymers are LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), MDPE (medium-density polyethylene), and HDPE (high-density polyethylene).

[0051] In one embodiment, the low-melting polymer component consists exclusively of ethylene homopolymers, e.g. mixtures of LDPE and LLDPE, each of which may be present in amounts of 10 to 90 wt.%, and 0 to 50 wt.% MDPE.

[0052] Preferably, the high-melting polymer component contains at least one polypropylene whose melting point, melting range, or crystallite melting point is significantly higher than that of the low-melting polymer component. Isotactic polypropylene is particularly suitable. Syndiotactic polypropylene can also be used, provided its melting point, melting range, or crystallite melting point is significantly higher than that of the low-melting polymer component.

[0053] The high-melting polymer component can include both propylene homopolymers and propylene copolymers with propylene as the main monomer.

[0054] Preferably, the backsheet film webs and nonwoven layers to be joined have a similar morphology in at least one formulation component.

[0055] According to the invention, the backsheet film is heated together with the nonwoven layer via a preferably non-stick coated heating cylinder and then passed through a cooled roller gap. Of course, it is also possible to use multiple heating cylinders or other heating methods such as infrared radiators.

[0056] In a preferred embodiment, the nonwoven layer is in direct contact with the surface of the heating cylinder. The backsheet film with the conductive print is carried along above it. The temperature of the heating cylinder is selected such that a component of the backsheet film is heated to a molten state via the area surrounding the heating cylinder, without affecting the conductive print. This temperature does not yet bring the nonwoven into a molten state.

[0057] Since the fleece, which is not yet in a molten state, rests on the heating cylinder, easy and very process-stable removal of the backsheet film is guaranteed.

[0058] In the subsequent cooled roller gap, the nonwoven-film composite is cooled to temperatures below the crystallite melting point of the backsheet film. The cooled roller gap preferably consists of a steel roller and a rubber roller operating under counter-pressure.

[0059] Unlike conventional thermobonding lamination processes, where two heated steel rollers use temperature and very high pressure to create a bond only at specific points, thermolamination produces bonded areas with full-surface lamination. Similar to conventional adhesive lamination processes, this offers the advantage of creating very flexible, adhesive-free structures using low pressure during the lamination process. Furthermore, unlike thermobonding laminates, there is no risk of material damage (holes, pinholes), which is particularly important for conductive printing.

[0060] In an alternative embodiment of the invention, it is conceivable that the arrangement consisting of the nonwoven layer and the backsheet film is bonded using a hot-melt adhesive. Bonding the film web to a nonwoven layer via ultrasonic welding is also conceivable.

[0061] The film can be printed after extrusion and before lamination. This allows printing on the backsheet film side, which is covered by the nonwoven layer in the final assembly. This achieves very good print quality because printing can be done on the smooth backsheet film. The conductive print can then be used for liquid detection, and at the same time, the backsheet film seals the assembly to be liquid-tight. Furthermore, the bonded nonwoven layer protects the conductive print during the subsequent processing into the disposable hygiene product.

[0062] Preferably, printing is integrated inline into the production process. The extrusion of the backsheet film is preferably followed by an embossing unit, and / or a chili roll system, and / or at least one cooling roller.

[0063] In one variant, the nonwoven film laminate undergoes ring rolling. This gentle process step mobilizes the fibers and increases the softness and smoothness of the laminate. These described changes in properties can be easily influenced by the geometry used and the degree of engagement of the ring rolling rollers. Only the properties of the backsheet film according to the invention allow for gentle treatment with ring rolling without significantly altering the area-specific resistance of the conductive print.

[0064] In one embodiment of the invention, the backsheet film is non-breathable and has a water vapor permeability of less than 500 g / m² in 24 h according to ASTM D6701-01. The basis weight of the non-breathable backsheet film is preferably less than 10 g / m², preferably less than 8 g / m², and particularly less than 6 g / m².

[0065] The specific dart drop according to ASTM D1709A of the arrangement is preferably more than 6 g per gram of polymer per square meter, so that the value is calculated from the mass of the "dart" divided by the specific weight of the film-nonwoven laminate as 6 g / (g / m 2< ) and / or the specific water column of the arrangement is more than 270 mm per gram of polymer per square meter, so that the value calculated from the water column divided by the specific weight of the film-nonwoven laminate as 270 mm / (g / m 2< ) .

[0066] These advantageous properties of the arrangement according to the invention are demonstrated by characteristic parameters. The arrangement exhibits a force of at least 0.3 N / in, preferably a force of at least 0.375 N / in, and in particular a force of more than 0.45 N / in, at 5% elongation per gram of polymer per square meter, so that the value is obtained by dividing the force per inch by the specific weight of the film-nonwoven laminate.

[0067] For example, if a value of 8.5 N / in is measured for a foil-fleece laminate with a specific weight of 18 g / m², the result is a value of 0.47222 (N / in) / (g / m²).

[0068] The force measurement at 5% elongation was performed according to ASTM D882. This results in a particularly rigid, non-breathable backsheet film, thus providing superior protection against tearing of the conductive print. Furthermore, due to the inventive formulation, the backsheet film is highly elastic, which is advantageous for protecting the conductive print and creating a pleasant feel.

[0069] In a further embodiment of the invention, the backsheet film is breathable. The breathable backsheet film has a water vapor permeability of more than 500 g / m² in 24 h according to ASTM D6701-01. The basis weight of the breathable backsheet film is preferably less than 20 g / m², more preferably less than 16 g / m², and particularly less than 12 g / m².

[0070] The specific dart drop according to ASTM D1709A of the breathable backsheet film is preferably more than 26 g per gram of polymer per square meter and / or the specific water column of the breathable backsheet film is more than 460 mm per gram of polymer per square meter.

[0071] The special mechanical properties of the breathable backsheet film are based on a specific formulation in combination with a very specific processing method, whereby blown extrusion is preferably used in the production of the film.

[0072] In one variant of the invention, the backsheet film comprises a low-melting polypropylene and a high-melting polypropylene.

[0073] It is particularly advantageous if the difference in the crystallite melting point between the low-melting polypropylene and the high-melting polypropylene in the backsheet film is more than 10 °C, preferably more than 15 °C, in particular more than 20 °C and / or less than 50 °C, preferably less than 40 °C, in particular less than 30 °C.

[0074] In one embodiment of the invention, the composition preferably comprises CaCO3 in a proportion of 40 to 60 wt.%. In a particularly advantageous embodiment of the invention, the composition of the breathable backsheet film comprises LDPE in a proportion of more than 2 wt.% and / or less than 10 wt.%.

[0075] The breathable backsheet film preferably exhibits a force of at least 0.5 N / in, preferably a force of more than 0.6 N / in, and particularly a force of more than 0.7 N / in per gram of polymer per m², each at 5% elongation. The force at 5% elongation was measured according to ASTM D882. The breathable backsheet film is very rigid, thus protecting the conductive print from potential damage. Furthermore, the backsheet film is highly elastic, resulting in a pleasant feel.

[0076] For example, if a value of 4.2 N / in is measured at 5% elongation, for a film with a specific gravity of 16 g / m² and a polymer content of 40%, the resulting value is (4.2 N / in / 16 g / m²) / 0.4 = 0.65625 (N / in) / (g / m²).

[0077] Thus, the arrangement according to the invention is characterized as being particularly lightweight, which creates a comfortable wearing experience.

[0078] This favorable stiffness combined with an advantageous softness of the arrangement is achieved through a specific composition, a targeted selection of polymers in combination with a specific manufacturing process.

[0079] The liquid detection device according to the invention is preferably used in the hygiene or medical sector, particularly for disposable hygiene products. These disposable hygiene products can be used by both the youngest and the oldest members of our society.

[0080] The surface resistance of the disposable hygiene product can be read using a reader that clips onto the product and forms a detection unit with the conductive print pattern. This transforms the disposable hygiene product into a smart diaper. When an adjacent liquid is conductively connected to the conductive print pattern, a significant change in resistance can be detected by the reader. The reader preferably has a Bluetooth transmitter / receiver unit, enabling location-independent transmission and display of a moisture event. Example 1: Liquid detection setup with a breathable backsheet film

[0081] In this example, the following components are used to manufacture the backsheet film: Quantity wt.% ingredient Density, g / cm³ < Crystallite melting point, °C 32 PP 0,9 140-142 58 CaCO3 - 6 PP 0,9 163-167 4 LDPE 0,92 111

[0082] The filler used is an inorganic filler in the form of calcium carbonate, preferably with a particle size of 0.8 to 2 µm.

[0083] To produce the backsheet film according to the invention, the polymer components are heated with the mineral fillers in an extruder, for example a compounding extruder, to a temperature significantly above the melting temperature of the polymer components (for example above 200°C) and fused together.

[0084] According to the invention, this is followed by blown film extrusion with cooling of the film web. In the subsequent monoaxial stretching process, the backsheet film is preferably stretched 100% in the machine direction.

[0085] In the inline process, the printing with conductive ink using flexographic printing is applied directly to the breathable backsheet film. The conductive ink preferably contains graphite pigments dissolved in a mixture of propyl acetate and propan-2-ol. Preferably, the conductive black ink contains fillers such as nitrate cellulose.

[0086] The backsheet film is then passed over a heated cylinder surface with a polypropylene-based, thermobonded nonwoven layer having a specific basis weight of < 14 g / m². This causes the backsheet film to be partially molten, forming large bonded areas with the nonwoven layer in the subsequent cooled roller gap. The conductive print on the breathable backsheet film is covered by the bonded nonwoven layer. In a final ring rolling process, the fibers of the film-nonwoven composite are gently activated, resulting in a pleasantly soft feel.

[0087] The area-specific resistance of the conductive print is determined using a test strip 30 cm long and 6 mm wide, corresponding to 50 square meters. The probes of a multimeter are pressed against the ends of the strip, and a resistance value of, for example, 57 kΩ is measured. This results in a calculated area-specific resistance of 1.14 kΩ / square. Example 2: Liquid detection setup with a non-breathable backsheet film

[0088] This example uses the following components: Quantity wt.% ingredient Density, g / cm³ < Crystallite melting point, °C 37,5 LDPE 0,92 111 25,5 LLDPE 0,92 123 16,25 PP 0,90 163 - 167 7,5 PP 0,90 140 - 142 8,0 TiO2 - 4,5 CaCO3 - 0,5 Thermostabilizer 0,93 0,25 Aids 0,94

[0089] To produce the film web according to the invention, the polymer components are heated in an extruder, for example a compounding extruder, to a temperature significantly above the melting point of the polymer components and fused together. Subsequently, blown film extrusion takes place with cooling of the multilayer film web. In the inline process according to the invention, the print is applied directly onto the non-breathable backsheet film using conductive ink via flexographic printing. An alternative conductive ink typically contains graphite pigments dissolved in a mixture of water and ammonium hydroxide.

[0090] The non-breathable backsheet film is then passed over a heated cylinder surface along with a polypropylene-based, thermobonded nonwoven layer with a specific basis weight of < 14 g / m². This process leaves the backsheet film partially molten, allowing it to form flat bonded areas with the nonwoven layer in the subsequent cooled roller gap. A final ring rolling process gently activates the fibers of the film-nonwoven composite, resulting in a pleasantly soft feel.

[0091] The area-specific resistance of the conductive print is determined using a test strip 30 cm long and 6 mm wide, corresponding to 50 Ω. The probes of a multimeter are pressed against the ends of the strip, and a resistance value of, for example, 56 kΩ is measured. This results in a calculated area-specific resistance of 1.12 kΩ / Ω.

[0092] Further advantages and features of the invention will become apparent from the description of various embodiments with reference to drawings and from the drawings themselves.

[0093] This shows Fig. 1 a schematic representation of a backsheet film with a print, Fig. 2 a schematic representation of the arrangement according to the invention, Fig. 3 another variant of the arrangement according to the invention, Fig. 4 a third variant of the arrangement according to the invention.

[0094] In Fig. 1 A backsheet film 1 with a conductive print 2 is shown, wherein the conductive print 2 is applied directly to the backsheet film 1 without an adhesion promoter layer. The backsheet film 1 is breathable and has a specific weight per unit area of ​​12 g / m². The weight per unit area of ​​the conductive print is less than 0.5 g / m².

[0095] Fig. 2 shows an arrangement according to Fig. 1 , wherein an additional nonwoven layer 3 is bonded to the backsheet film 1. The nonwoven layer 3 has a specific basis weight of 12 g / m².

[0096] In Fig. 3 An arrangement is shown in which the backsheet film 1 is provided with a conductive print 2, wherein the nonwoven layer 3 is arranged on the opposite side of the conductive print 2.

[0097] Fig. 4 shows a design according to Fig. 2 , in which the backsheet film 1 is not breathable and has a basis weight of 6 g / m 2<.

Claims

1. Arrangement (4) for liquid detection in disposable hygiene articles, characterized in that the arrangement (4) comprises a backsheet film (1) with a conductive print (2), wherein the basis weight of the conductive print (2) is less than 3 g / m2 , wherein the backsheet film (1) is not designed to be breathable and has a water vapor transmission rate of less than 500 g / m2 in 24 h according to ASTM D6701-01, wherein the basis weight of the non-breathable backsheet film (1) is less than 10 g / m2 or the backsheet film (1) is designed to be breathable and has a water vapor transmission rate of more than 500 g / m2 in 24 h according to ASTM D6701-01, wherein the basis weight of the breathable backsheet film (1) is less than 20 g / m2.

2. Arrangement according to claim 1, characterized in that the conductive print (2) has a surface resistance of less than 10 kΩ, preferably less than 6 kΩ, preferably less than 4 kΩ, and in particular less than 1 kΩ.

3. Arrangement according to claim 1 or 2, characterized in that the basis weight of the conductive print (2) is less than 2 g / m2, preferably less than 1 g / m2, in particular less than 0.5 g / m2.

4. Arrangement according to one of claims 1 to 3, characterized in that the backsheet film (1) printed with the conductive imprint (2) does not exhibit any abrasion according to the rub-off test.

5. Arrangement according to one of claims 1 to 4, characterized in that the arrangement (4) has a nonwoven layer (3), wherein connecting regions are arranged between the nonwoven layer (3) and the backsheet film (1).

6. Arrangement according to claim 5, characterized in that the connecting regions are formed as a form-fitting composite of material from the nonwoven layer (3) and solidified material of the backsheet film (1).

7. Arrangement according to one of claims 1 to 6, characterized in that the conductive imprint (2) is arranged between the backsheet film (1) and the nonwoven layer (3).

8. Arrangement according to one of claims 1 to 7, characterized in that the backsheet film (1) is not designed to be breathable, whereby the basis weight of the backsheet film (1) is less than 8 g / m2, in particular less than 6 g / m2.

9. Arrangement according to claim 8, characterized in that the specific dart drop of the arrangement (4) is more than 6 g per gram of polymer per square meter and / or - the specific water column of the arrangement (4) is more than 270 mm per gram of polymer per square meter.

10. Arrangement according to claim 8 or 9, characterized in that the arrangement (4) - has a force of at least 0.3 N / in per gram of polymer per m2, - preferably a force of at least 0.375 N / in per gram of polymer per m2, - in particular a force of more than 0.45 N / in per gram of polymer per m2, in each case at 5% elongation.

11. Arrangement according to one of claims 1 to 7, characterized in that the backsheet film (1) is designed to be breathable, wherein the particular basis weight of the backsheet film (1) is less than 16 g / m2, in particular less than 12 g / m2.

12. Arrangement according to claim 11, characterized in that - the specific dart drop of the backsheet film (1) is more than 26 g per gram of polymer per square meter and / or - the specific water column of the backsheet film (1) is more than 460 mm per gram of polymer per square meter.

13. Arrangement according to claim 11 or 12, characterized in that the backsheet film (1) has a force of - at least 0.5 N / in per gram of polymer per m2, - preferably a force of more than 0.6 N / in per gram of polymer per m2, - in particular a force of more than 0.7 N / in per gram of polymer per m2 in each case at 5% elongation.

14. Arrangement according to one of claims 1 to 13, characterized in that the conductive imprint (2) is arranged directly on the backsheet film (1).