ELASTIC ELEMENT FOR DIAPER.

Abstract

The invention relates to an elastic diaper element with an elastic layer (1) and outer layers (2, 3) made of nonwoven material. The diaper element has connection regions (4, 8) for connecting the outer layers (2, 3) to the elastic layer (1). The connection regions (4, 8) comprise zones (7, 9) in which a shape-closure bond is formed between the nonwoven material and the solidified material of the elastic layer (1).

Description

ELASTIC ELEMENT FOR DIAPER Field of invention The invention relates to an elastic diaper element with an elastic layer and an outer layer of a non-woven material. Background of the invention Diapers use various fastening systems. These can be achieved with either an adhesive film or a tape with hooks and loops. Hook and loop fasteners are highly popular with users, as these closure systems are also commonly found in clothing, often in the form of Velcro-style closures. For products intended for temporary use, inexpensive crochet hooks and loops are used. These diaper fastening combinations are described, for example, in documents WO96 / 22065, EP 719 533, EP 721 770, and WO 95 / 25496. Many diaper fastening systems include a fiber material held against the body, called the receiving zone, and a corresponding diaper tab. The diaper tab consists of a multi-layered laminate and has a material on at least one side that hooks onto the receiving zone when the diaper is fastened. To enhance comfort during use, these diaper flap laminates feature elastic components which, through the elastic's rebound force, ensure a snug fit to the body's shape. For a pleasant tactile sensation, the elastic components, which are mostly applied as films, are covered with textile materials. Studies show that closing a diaper tab exerts a maximum force of approximately 10 N. After this stretching effort, the diaper tab continuously retracts due to its elasticity. The range between 0 and 100% stretch, or between 0 and 10 N, is designated as the functional range. The most common procedures for producing laminates from an elastic film and a fleece are heat bonding or the use of adhesives. In the case of heat bonding using a stamping roller (a steel roller with engravings), high temperature and pressure fuse the film material and the fleece together. This process has the disadvantage that the films can be damaged and pinholes can form. Furthermore, this method only results in a spot bond. Adhesives are still used to produce almost all commercial components of diapers. However, these adhesives cause odor problems, for example, due to the release of styrene. Children wear diapers for several years, often 24 hours a day. Therefore, it is essential that diapers be as free of harmful substances as possible. In the case of standard diapers, it has been possible to reduce the use of adhesives in the diaper tabs. Until now, almost all standard diaper tabs have been bonded together with adhesives, joining the top and bottom layers of fleece to the intermediate elastic film. The use of glue is also objectionable for environmental reasons. It is estimated that more than 22,000 tons of glue are used annually in the production of diaper tabs. The use of these glues is associated with additional costs. EP 3 082 702 B1 describes a process for forming an elastic fleece laminate. The laminate is fed between the gap between two rollers. One roller has ribs. The laminate is then passed through a second gap formed by connecting rollers. The connecting rollers are provided with a pattern. The pattern preferably covers 10 to 60% of the total surface area of ​​the outer side of the fleece. Document EP2951016B1 describes a process for producing a glueless laminate. A substrate of a thermoplastic layer and layers of fleece placed on top of it form a laminate by bonding through the application of heat to a thermoplastic layer, via infrared radiation and subsequent compression, and then cooling. The document DE 103 04 370 B4 describes a process for producing transversely elastic material strips, consisting of an elastic carrier film made of a polymer, to which a fleece strip has been applied on the upper and lower sides of the carrier film. The connection to form the laminate is made by welding together the surfaces of spot welds arranged in a grid pattern. Document EP 0 714 351 B1 describes a process for producing a film from a fiber fleece and an elastomeric film. The elastomeric film and the fleece are bonded in a bonding unit. An elastomeric extrudate is then extruded at a temperature above its softening point. The compression rollers used create a flat bond between the elastomeric film and the fleece. The laminate is then subjected to a stretching process. During this process, a consistent flat product is formed from the elastic layer and the fleece. The elastic layer is bonded to the fleece across the entire surface of the laminate. Such a laminate can only be activated by understretching. EP 1 921 192 Al describes a multi-layered elastic material band made of fleece and polymer films. At least one of the fleece layers, after extrusion and before bonding with the polymer film, is fixed by means of water jets, such that it can be easily stretched transversely and the material band is elastically deformable. EP 2 228 200 Al describes an elastic laminate for diaper fasteners. The elastic laminate comprises outer layers of nonwoven material, between which an elastic film is laminated. One of the two outer layers consists of a fleece compacted by water jets. The fleece is stretched in an axial direction in the area of ​​the elastic film. EP 2 406 070 B2 describes an elastic laminate for diaper fasteners. It comprises outer layers of nonwoven material with an elastic film laminated between them. One of the outer layers consists of a water-jet-compacted fleece stretched in an axial direction. The layers of the elastic laminate are joined by ultrasonic spot welding or by adhesive. WO 2006 / 024394 A1 describes a process for the production of fleece-film laminates for hygiene products. A starting fleece web, together with an initial film web, is fed into a heated cylinder. There, both webs are heated together to a temperature above the crystalline melting point of the film web and below the crystalline melting point of the fleece web. The fleece web makes contact with the cylinder. The product formed on the heated cylinder is then fixed and cooled in a die-cutting mill. The die-cutting mill consists of a die-cutting cylinder and a rubber roller. The product is then fed into a drawing unit. Drawing is carried out by means of annular rotating rollers in the transverse direction. Summary of the invention The objective of the invention is to provide an elastic diaper element that is safe for health and environmentally sustainable. The diaper element must not release any odor. Furthermore, it must exhibit good tear resistance and an optimal stretch curve. It must also offer a pleasant feel and, when stretched, provide sufficient but not excessive resistance, so that the stretching effort is comfortable for the user. To achieve this, the structures of the individual layers must not be technically damaged, so that the mechanical properties of the laminate are maintained. Upon completion of the stretching effort, the laminate, due to its elasticity, must recover its shape as much as possible. The diaper element must guarantee comfortable wear and a secure fit. This task is accomplished according to the invention by means of a diaper element, a method, and its use in accordance with the main claims set forth below. Preferred variants can be found in the dependent claims, the claim, the embodiment, and the drawings. According to the invention, the diaper element features connection areas between the outer layers of nonwoven material, which are provided with an elastic layer. These connection areas have zones where the nonwoven material is embedded in the more rigid material of the elastic layer. The elastic layer is applied between the outer nonwoven layers by cast extrusion, and the layers are connected by a structured roller that, according to the invention, forms specific connection regions. In these regions, the thermally unaltered nonwoven material exerts pressure on the molten elastic layer and / or the molten elastic material embedded in a layer of nonwoven material. According to the invention, this laminate is used as a diaper component. Its use as a diaper closure element, preferably as a diaper tab, proves advantageous. The laminate is also suitable for use as a waistband for a diaper. Qzcbnn / Lznz / E / Yii diaper, which features laminated strips that are at least partially elastic. The production of the laminate, in addition to the extruder's ability to melt the material, requires no other energy input. The molten material cools between the rollers. This solidifies the molten material and forms the bonding regions according to the invention. These regions are formed in such a way that the layers of nonwoven material are not subjected to external thermal loads, as would be the case with ultrasonic welding or hot lamination. This prevents the formation of holes. No glue is required to produce the laminate according to the invention. By selectively heating the elastic layer through vacuum extrusion, while simultaneously generating an inside-out heat current during the bonding stage, also through the outer nonwoven layers, the elastic layer's load-bearing structure is maintained. Ensuring an inside-out heat current during the bonding process produces a laminate with particularly advantageous properties as a diaper tab. The outward flow of thermal energy can thus be specifically controlled. In a particularly advantageous embodiment of the invention, at least one cooling roller is used. By reducing the surface temperature of the cooling roller, the flow of thermal energy from the inside out can be specifically increased to produce a diaper tab or a diaper waistband laminate. The elastic polymer film, after extrusion, is molten and liquid at a temperature preferably above 210°C. Cooling is preferably carried out in a joining stage by means of a roller at over 100°C, preferably approximately over 150°C and especially over 160°C, such that after the first pair of rollers used for joining the layers, the laminate is almost at room temperature. ozcbnn / ίζηζ / Β / γι In one variant of the invention, rollers with different surface temperatures are used during the joining stage. This allows the heat flow to be divided, such that a greater heat flows outward through one layer of nonwoven material than through another. By achieving an advantageous ratio of the outward heat flow, optimal properties can be obtained in the laminate for use as a diaper tab or waistband. Cooling rollers can be formed with raised sections to create a die. Two cooling rollers can also be used. A flat cooling roller can be used in conjunction with a raised, non-cooled roller, or vice versa. The rollers can be made of materials such as metal and / or rubber. According to the invention, the laminate has connection regions with the nonwoven material and with the solidified elastic material. After the elastic material is extruded between the nonwoven bands in selected regions, the fleece material is compressed into the elastic layer, which is still in a molten and liquid state. Zones are formed in which the nonwoven material forms a shape-fitting closure with the solidified material of the elastic layer. This results in specific connection regions between the solidified elastic material and the nonwoven material. Unlike the current process, compression is not applied across the entire surface. The connection regions according to the invention are preferably in the form of bands and / or mesh and / or notches and / or grids. The connection regions may be formed by multiple sequential rows. Within a row, a straight and / or wavy course is possible. The orientation of the connection regions preferably extends perpendicular to the pull direction of the diaper tab or waistband, such that the individual rows are oriented transversely to the pull direction of the diaper tab or waistband. For optimal lamination of the diaper's tongue or waistband, it is important that the proportion of protruding areas and depressed areas is correct, which for the structured rollers used is called the crest-valley ratio. Preferably, the connection areas comprise less than 90% of the total surface area of ​​the laminate. In a particularly advantageous embodiment of the invention, the areas according to the invention can be less than 80%, preferably less than 70%, and especially less than 60% of the total surface area of ​​the laminate. Accordingly, the connection areas preferably comprise more than 10%, preferably more than 20%, and especially more than 30% of the total surface area of ​​the laminate. It proved particularly advantageous for the connection regions to have a width greater than 0.1 mm, preferably greater than 0.3 mm, especially greater than 0.6 mm, and / or a width less than 8 mm, preferably less than 6 mm, especially less than 4 mm. The connection regions are preferably shaped like bands perpendicular to the direction of pull of the diaper's tab or waistband. Surprisingly, it was determined that a laminate compressed specifically in certain areas is very suitable for use as the diaper tab or waistband. Activation allows for optimal super-stretching of one layer of nonwoven material in the transverse direction, thereby breaking a large proportion of the bonds between the nonwoven fibers within that layer. Simultaneously, the other layer of nonwoven material undergoes a transverse orientation, directing the fiber stacks perpendicular to the pull direction of the diaper tab or waistband, thus absorbing the force when used as the diaper tab or waistband. In a preferred embodiment of the invention, the connection regions have ozcbnn / ίζηζ / Β / γι zones located on the outside, in which the non-woven material of the outer layers is compressed, but not completely melted and / or in which the non-woven material of the outer layers is not melted. Between the connection regions are areas where the fibers of the nonwoven layer are not, for the most part, tightly bonded to the elastic material. These areas contribute only negligibly to the connection between the individual layers, as weak cohesion between the elastic layer and the nonwoven layer is only present at the direct contact surface. These "unbonded areas" preferably comprise more than 10%, especially more than 20%, and preferably more than 30% of the total surface area. Preferably, in these areas, more than 50%, preferably more than 65%, and especially more than 80% of the fibers are not tightly bonded to the elastic layer material. It has proven particularly advantageous for these unconnected regions to have a width greater than 0.1 mm, preferably greater than 0.3 mm, especially greater than 0.6 mm, and / or a width less than 8 mm, preferably less than 6 mm, especially less than 4 mm. The unconnected regions are preferably shaped like bands perpendicular to the direction of pull of the diaper tab or waistband. To produce the connection regions, rollers with a surface structure with a ridge height greater than 100 pm, preferably greater than 300 pm, especially greater than 500 pm, preferably greater than 300 pm, especially greater than 500 pm and / or less than 1.8 mm, preferably less than 1.6 mm, especially less than 1.4 mm are preferably used. In a particularly preferred embodiment of the invention, at least one layer of nonwoven material consists of a carded fleece. Carding in fleece production serves to orient the first loose textile fibers, forming a fleece. The carded fleece The Qzcbnn / ίζηζ / E / γι used consists preferably of polypropylene fibers and / or mixtures of different types of fibers, such as polypropylene / viscose, polypropylene / polyamide, polypropylene / polyester, etc. According to the invention, the original bonds present within the layer of carded nonwoven material in the diaper flap or waistband are mostly partially separated. The other layer of nonwoven material, on the other hand, maintains its basic structure and forms a functional, force-absorbing fleece. According to the invention, the second nonwoven layer consists of a fleece compacted with water jets. Water jet compaction gives the fleece layer a high stretchability in the transverse direction. Through water jet compaction, the fibers change their orientation within the fleece, transforming the original two-dimensional fiber orientation into a three-dimensional one. The fibers become more tightly intertwined within the fleece. This layer of nonwoven material preferably has a surface specific gravity of 5-80 g / m², preferably 10-70 g / m², and especially 1525 g / m². Preferably, in the case of the water-jet compacted fleece layer, it is made from endless filaments. Due to their production process, these fibers are stacked in loops, providing ample opportunity for the hooks to attach. Spinnable polymers, such as polyester, PLA, and polyolefins, especially polypropylene and polyethylene, can be used as materials to produce the endless filaments. They primarily consist of polypropylene and / or polyethylene material. In the case of the elastic layer, it is preferably a block copolymer of polypropylene and polyethylene. The elastic film has a specific gravity of 5-140 g / m², preferably 10-130 g / m², and more preferably 20-40 g / m². Polymers containing styrene are completely omitted according to the invention. Brief description of the figures Other advantages and features of the invention are apparent from the description of an exemplary embodiment with the aid of a drawing, and in the drawing: Figure 1 shows a cut through a diaper element according to the invention. Detailed description of the implementations of the invention In Figure 1, the laminate includes an elastic layer 1, which is placed between two outer layers 2, 3 made of nonwoven material. The nonwoven material layer 2 shown at the top of the drawing, in this embodiment, is a water-jet compacted fleece, for which a spun fleece consisting of endless filaments is used. The second layer of nonwoven material 3 is a carded fleece, which, prior to the process, was compacted to the laminate by means of bonding points. This is achieved using a technique known as thermal bonding. Thermal bonding is a process for the thermal solidification of fleeces. This significantly increases the bond strength and allows for the production of lightweight fleeces. According to the invention, during the production of the laminate, in an activation stage, the laminate is preferably stretched in the transverse direction by means of annular rolling, thereby continuously breaking the internal bonds of the carded nonwoven material layer 3. Simultaneously during activation, the other layer of nonwoven material 2 of the water-jet-compacted fleece remains functional and absorbent of forces. In the case of activation, the endless filaments compacted by water jets in the nonwoven material layer 2 orient themselves in the transverse direction. The laminate according to the invention exhibits optimal performance as Qzcbnn / Lznz / E / Yii diaper tab or waistband, since on one side it can be stretched adequately, but nevertheless produces a sufficient counterforce, so that the user has a pleasant sensation when stretching the diaper tab or waistband. When the diaper tab closes, it produces a maximum force of approximately 10 N. When the traction is no longer applied, the diaper tab, according to the invention, continuously recovers due to its elasticity. If the diaper element according to the invention is configured as a diaper tab, it preferably has a width between 40 and 120 mm, especially between 40 and 100 mm, preferably between 50 and 80 mm and / or a length preferably between 40 and 200 mm, especially between 60 and 180 mm, preferably between 80 and 160 mm. If the diaper element according to the invention is configured as the diaper waistband, it has proven particularly advantageous when the diaper waistband has, at least in some areas, elastic bands of the laminate according to the invention. The diaper waistband preferably has a width of between 10 and 160 mm, especially between 20 and 140 mm, and preferably between 30 and 120 mm, and / or a total length preferably between 300 and 800 mm, and especially between 400 and 600 mm. If the diaper waistband is provided with bands according to the invention, these bands preferably have a length of between 40 and 200 mm, especially between 60 and 180 mm, and preferably between 80 and 160 mm. In the embodiment, elastic polyolefin monofilms are used as the elastic layer 1. Preferably, these are thermoplastic polymers. Specifically, polypropylene-polyethylene block copolymers are used, for example, from the Exxon Vistamaxx series (polypropylene-based): VM 6102 or VM6202 or VM 7810 and / or from the Dow Infuse series (polyethylene-based): Infuse 9507, Infuse 9107. According to the invention, specific connection regions 4 ozcbnn / ίζηζ / Β / γι were included in the laminate, which, compared to regions 5, have a much stronger connection between the individual layers 1, 2, and 3 of the laminate. The cohesive forces acting between layers 1, 2, and 3 in connection regions 4 are greater by a factor greater than 3, preferably a factor of 5, and more preferably a factor of 10, than in regions 5. In the connection regions 4, the nonwoven material is compressed within the molten material of the elastic layer 1, whereby, according to the invention, no external heat is applied during the connection process. The connection regions 4, according to the invention, have different zones 6 and 7. In the outer zone 6, the fleece material of the nonwoven layer 2 is indeed compacted, but is neither partially nor completely melted. In the outer zone 6, a form-fit bond between the solidified elastic material and the nonwoven material is not required. In the inner zone 7 of the connection region 4, a form-closure bond is formed between the solidified elastic material and the nonwoven material. Here, the nonwoven material does not need to be melted; instead, the fibers can be pressed into the elastic melt, resulting in a form-closure bond after the solidification of the elastic layer 1. Alternatively, at least some fibers of the nonwoven material may already be fused in the inner zone 7. It is also possible that the nonwoven material is completely fused into the elastic melt in the inner zone 7. In all cases, a form-closure bond is formed between the nonwoven material and the solidified material of the elastic layer 1 after the solidification of the elastic material in the inner zone 7. The triple laminate shown in Figure 1 is joined together by a pair of rollers. The profiled roller with raised ridges, seen from above in the drawing, compresses the nonwoven layer 2 into the elastic layer 1. Below this is a counter roller with a flat surface. During the production of the laminate shown in Figure 1, a cooling roller is used as a counter roller. The cooling roller is made of steel. The structured roller acting from above is an uncooled roller made of a rubber-like material. The rollers used for the connection operate at a distance. A fixed distance is maintained between the cooling roller and the forming roller. This distance amounts to at least 20% of the combined thickness of the three layers 1, 2, and 3. Opposite connection regions 4 are connection regions 8. These are formed in such a way that they transmit the pressure produced by the crests of the profiled roller, which compresses the non-woven material layer 2 into the elastic layer and thereby compresses connection regions 8, the elastic layer 1 into the non-woven material layer 3. This forms interior zones 9, in which the non-woven material forms a shape closure with the solidified material of the elastic layer 1. Here, the nonwoven material does not need to be melted; instead, the fibers can simply be introduced into the elastic melt, such that after the solidification of the elastic layer 1, a form-closure bond is formed. Alternatively, in the inner zones 9, at least some fibers of the nonwoven material may be melted. It is also possible that, in the inner zones 9, the nonwoven material is completely melted into the elastic melt. In all cases, after the solidification of the elastic material in the inner zone 9, a form-closure bond is formed between the nonwoven material and the solidified material of the elastic layer 1. The connection regions 8 also feature an outer zone 10, in which the fleece material of the nonwoven layer 3 is compressed, but not partially or completely melted. A form-closure bond between the solidified elastic material and the nonwoven material is not necessarily required in the outer zone 10. According to the invention, the diaper element between the connection regions 4, 8 has zones 11 in which the fibers of the nonwoven material layers in question 2, 3 are, for the most part, neither partially nor totally fused. Particularly on the boundary surface 5 of the elastic layer 1, the fibers may be partially or totally fused. The fraction of zones 11 in the total surface of the laminate preferably amounts to more than 10%, especially more than 20%, preferably more than 30% and / or less than 60%, especially less than 50%, preferably less than 40%. In the outer sections of zones 11, the fibers of the nonwoven material layers 2 and 3 are largely unaffected by thermal influences, as the fibers according to the invention are not subjected to any external thermal load. In zones 11, the fibers are primarily subjected to mechanical stress through stretching in the transverse direction during the activation stage. The laminate preferably has a specific surface weight greater than 10 g / m2, especially greater than 30 g / m2, preferably more than 40 g / m2, and / or less than 400 g / m2, especially less than 300 g / m2, preferably less than 200 g / m2. In a particularly advantageous embodiment of the invention, the surface weight is between 50 and 150 g / m2. In the embodiment, the connection regions 4 and 8 and the non-connection regions 11 are formed as bands, where the bands extend transversely to the pull direction of the diaper element. The bands have a width between 0.5 mm and 2 mm. In the embodiment, the connection regions 4 and 8 and the non-connection regions 11 have the same width and both have a width of 1.2 mm, such that the surface area ratio of the connection regions 4 to the non-connection regions 11 is equal.

Claims

CLAIMS 1. Elastic diaper element with an elastic layer (1) and outer layers (2,3) made of non-woven material, characterized in that the diaper element has connection regions (4,8) of the outer layers (2,3) with the elastic layer (1), wherein the connection regions (4,8) have zones (7,9) in which there is a shape-closure bond between the non-woven material of the outer layers (2,3) and the solidified material of the elastic layer (1).

2. Elastic element for diaper according to claim 1, characterized in that the connection regions (4, 8) amount to less than 90%, preferably less than 80%, especially less than 70% and / or more than 10%, preferably more than 20%, especially more than 30% of the total surface.

3. Elastic element for diaper according to claim 1 or 2, characterized in that, between the connection regions (4,8) there are zones (11) in which there is mostly no closure of the non-woven material and the solidified material of the elastic layer (1).

4. Elastic element for diaper according to any one of claims 1 to 3, characterized in that the connection regions (4,8) have outer zones (6, 10), in which the non-woven material of the outer layers (2,3) is compacted but is not partially or totally melted.

5. Elastic element for diaper according to any one of claims 1 to 4, characterized in that an outer layer (3) consists of a carded fleece, wherein the fleece preferably has a specific weight of 10 to 40 g / m2, especially 15 to 25 g / m2.

6. Elastic element for diaper according to any one of claims 1 to 5, characterized in that the outer layer (2) consists of a water-jet compacted fleece, preferably a water-solidified fleece of endless filaments, wherein the fleece preferably has a specific weight of 10 to 70 g / m2, especially 15 to 25 g / m2.

7. Elastic element for diaper according to any one of claims 1 to 6, characterized in that the elastic layer (2) consists of a block copolymer of polypropylene and polyethylene, in which the elastic film preferably has a specific weight of 5-100 g / m2, especially 20-40 g / m2.

8. Procedure for the production of a laminate for elastic elements for diapers with the following steps: extrusion of a layer of elastic film (1) between two layers of non-woven material (2,3), - connection of the layers (1, 2, 3) forming a laminate between rollers, wherein at least one of the rollers has elevations.

9. Method for the production of a laminate according to claim 8, characterized in that at least one of the rollers is a cooling roller.

10. A method for producing a laminate according to claim 8 or 9, characterized in that when a layer of non-woven material (3) is activated, internal bonding points between the fibers are broken and / or the other layer of non-woven material (2) is maintained as a functional and force-absorbing layer of non-woven material (2) and undergoes a transverse orientation.

11. Method according to any one of claims 8 to 10, characterized in that the roller elevations have a height greater than 100 pm, preferably more than 300 pm, especially more than 500 pm and / or less than 1.8 mm, preferably less than 1.6 mm, especially less than 1.4 mm.

12. A method according to any one of claims 8 to 11, characterized in that the laminate is stretched in the transverse direction to such an extent that in the case of one of the layers of non-woven material (3) the breaking stretch is exceeded, preferably exceeded by more than 20%, especially by more than 40%.

13. A method according to any one of claims 8 to 12, 5 characterized in that the laminate is stretched in the direction to such an extent that in one of the layers of non-woven material (2) the breaking stretch is not reached.

14. Use of one of the laminates produced according to one of claims 8 to 13 as an elastic element for a diaper, in particular as a diaper tab or waistband.

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