Adhesive fastener and diaper having such an adhesive fastener

Abstract

To provide an adhesive fastener that can be disposed of in an environmentally friendly manner. [Solution] The present invention relates to an adhesive fastener and a diaper having such an adhesive fastener, the adhesive fastener being made of at least one plastic material having a plurality of hook means integrally connected to a substrate 10, each hook means being in the form of a stem 14 with a head 12 and projecting above the substrate 10, and at least a portion of the plastic material used being biodegradable.

Description

[Technical field]

[0001] The present invention relates to at least one adhesive fastener made of a plastic material having a plurality of hook means integrally connected to a substrate, each hook means taking the form of a stem having a head and projecting above the substrate, and further to a diaper having at least one such adhesive fastener. [Background technology]

[0002] Baby diapers, incontinence diapers, etc. used on the world market are usually composed of paper diapers, which generate a considerable amount of waste and whose environmentally friendly disposal must be considered as a problem. Today, disposable diapers are currently available on the market in an environmentally friendly form, the so-called eco-friendly diapers, which have a high proportion of biodegradable components that are obtained at least partially from sustainable resources. These eco-friendly diapers, despite being about 85% biodegradable, are not treated as organic waste collections and are usually disposed of through standard waste collections intended for combustion in heating power plants. This cannot exactly be considered environmentally friendly.

[0003] Republished German Patent Publication 10 2019 006 683 also discloses a baby or incontinence diaper consisting of an outer shell and an absorbent body connected to this shell, which can be separated from the shell by a mechanical closure system acting between the outer shell and the absorbent body, typically in the form of a correspondingly interactive adhesive fastener. This helps to reduce the burden on the environment, especially when the absorbent body is made of a biodegradable pulp material that can be mechanically separated from other components, such as the outer shell of the diaper, and is discarded in organic waste collections. Special outer shells of the diapers, especially if made of compostable plastic material, can be returned directly to the recycling system.

[0004] Such baby diapers and incontinence diapers are typically equipped with laterally arranged closure tabs by means of which the diaper can be closed after use in a user-friendly manner. For this purpose, so-called hook-and-loop fasteners (hook-and-loop fasteners) are usually used, which consist of a hook material on one side and loops or fibers which can be hooked into the hook material on the other side in a releasable manner and can also be formed by the surface material of the diaper itself. Such a closure system is known from the patentee's DE-OS 196 46 318, as well as a method for producing the same. For the above-mentioned adhesive fasteners, which are typically sewn or glued to the closure tabs of the baby diaper, high-quality, temperature-resistant plastic materials are used, preferably polyamides, in particular polyamide pellets or polyamide-containing mixtures of thermoplastics. However, such plastics, although functionally reliable and useful in application, have the disadvantage that the above-mentioned plastic materials make them difficult to recycle. In particular, this substance is not easily biologically degradable. This makes its use in diapers overall more difficult to dispose of and prepare environmentally friendly diapers, even if the rest of the production materials are fully biodegradable.

[0005] The object of the present invention is therefore to go beyond the prior art and to further improve the known adhesive fasteners so that they can be disposed of, if necessary, in an environmentally friendly manner, including in the field of application of such adhesive fasteners, such as, for example, in the field of diapers of all kinds. Summary of the Invention [Means for solving the problem]

[0006] This object is achieved by an adhesive fastener having generally the features of claim 1 and by a diaper having at least one such adhesive fastener according to the features of claim 7.

[0007] According to the characterizing portion of claim 1, an essential feature of the adhesive fastener according to the invention is that at least a part of the plastic material used is biodegradable and / or bio-based. Preferably, such adhesive fasteners are used in diapers whose manufacturing or use materials are constructed such that at least about 85% of the material is biodegradable and / or bio-based.

[0008] The biodegradable plastic material is preferably polycaprolactone, polybutylene or polybutylene succinate. The material polycaprolactone is based on a petroleum product, but the plastic can be biologically degraded by the action of microorganisms such as fungi and bacteria. Furthermore, decomposition can be accelerated by the use of enzymes, and biological decomposition occurs substantially by oxidation and hydrolysis processes, forming water, carbon dioxide, or methane, and the products of dissociation of biomass. Another biodegradable plastic material is polybutylene, more precisely polybutylene adipate terephthalate. This plastic material can contain more than 30% of biobased carbon content and has technical properties similar to LDPE (low density polyethylene). Another suitable agent for adhesive fasteners is polybutylene succinate, which is based on fossil raw materials containing chemical compounds from the group of linear aliphatic polyesters, but can also be constructed from renewable raw materials. Its technical properties are again comparable to those of LDPE or polypropylene.

[0009] Cellulose acetate can be used as a bio-based plastic material for adhesive fasteners, it belongs to the thermoplastics and can be constructed from semi-synthetic fibers. In addition, bio-based polyethylene can be used, which can be produced both petrochemically and from alcohols such as bioethanol. In the case of polyethylene furanoate, this is a 100% recyclable plastic material. All of the above bio-based plastics can be produced, at least in part, based on renewable raw materials, making their use particularly environmentally friendly.

[0010] It is particularly advantageous to produce adhesive fasteners from bio-based, biodegradable plastic materials. For this purpose, polylactides, also known by the term polylactic acid, can be used as plastic materials. Further examples are polyhydroxyalkanoates and thermoplastic elastomers, including thermoplastic styrenic block copolymers (TPE-S). All the plastic materials used make it possible to construct the substrate of the adhesive fastener in such a way that it is a plastic film with a low melting point, which allows adhesive-free connection to other components by thermal bonding, such as components of the diaper, in particular in the form of their closure tabs.

[0011] When the adhesive fastener is used in a diaper, it is desirable that the substrate film thickness is 0.30 mm to 0.36 mm at the melting temperature of the material of 70° C. Such an adhesive fastener, as an additional adhesive fastener of the peelable adhesive closure member, has a peel adhesion strength of 2.34 N / cm to the loop or ringlet material. 2 The average value of the .lambda.

[0012] Such diapers, especially with these adhesive fasteners in the region of their closure tabs, allow complete biological degradation of the entire used diaper.

[0013] It will be appreciated that the individual plastic materials mentioned above may also be mixed with one another to form compounds which may be provided with corresponding fillers for their stabilization. [Brief description of the drawings]

[0014] The adhesive fastener according to the invention and a diaper comprising at least one such adhesive fastener are explained in more detail below with reference to the drawings, which are shown in schematic form and not to scale, in which: [Figure 1] FIG. 2 is a perspective view of a portion of an adhesive fastener. [Diagram 2] FIG. 2 is a plan view of the diaper pressed flat in the plane of the drawing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The adhesive fastener, part of which is shown in FIG. 1, has a plurality of hook means integrally connected to a film-like substrate 10, the hook means being symmetrically structured, each hook means being in the form of a stem 14 connected to a head 12. To produce this adhesive fastener, a method is used in which a moldable plastic material is fed into a forming zone between a roller-like printing tool and a roller-like forming tool, the roller-like forming tool being driven so that the substrate is formed in the forming zone and conveyed in a given conveying direction. As a shaping zone, a sieve is fixed on the forming tool and has individual forming cavities, the opposing boundary walls of which, at least in their longitudinal parts, have a continuous convex contour for forming the stems of the respective stems 14. The outwardly projecting heads 12 can be re-calendered after leaving the forming tool to form a single head plane. Moreover, it is rotationally symmetrical like the head 12, to create a resistant stem 14. Such a molding manufacturing method is also known in technical terms as the "chill roll method".

[0016] In addition to the abovementioned plastic materials, polyolefin-based plastic materials have proven to be particularly advantageous, with additives as exemplified in WO 2018 / 095905.Furthermore, thermoplastically processable biodegradable molding compositions containing fully biodegradable polyesteramides and thermoplastically processed cellulose derivatives, as described in EP 0 780 439, are suitable.

[0017] This list of suitable biodegradable and / or biobased plastic materials is not exhaustive.

[0018] Figure 2 shows the outer shell 16 of a disposable diaper in the form of a flat-open baby diaper or an adult incontinence diaper. The outer shell 16 is tapered along its two opposite longitudinal edges 18 to form leg openings for the user. Two longitudinal regions 20 forming a kind of cuff are made of an elastic material customary in diapers, which increases the wearing comfort for the user. At the upper end of the outer shell 16 as seen from the viewing direction of Figure 1, two flap-like closure tabs 22 are attached in the conventional manner, by means of which the diaper can be fastened around the user and closed by rolling up after use. For this purpose, the two closure tabs 22 are provided towards their two free ends with adhesive fasteners 24 with closure material, as shown in detail in Figure 1. The adhesive fasteners 24 are attached along the two longitudinal edges 18 at the head side of the diaper and are fixed to the front side of the diaper in the so-called target area of ​​the diaper, allowing the diaper to be placed securely on its wearer, the adhesive fasteners 24 being arranged like strips at the ends of the closure tabs 22.

[0019] Along the two longitudinal edges 12, in the viewing direction of Fig. 2, two cover strips 26 extend from top to bottom and to the left and right of the centre of the sheath 16, leaving two end regions 28 free, for accommodating an absorbent body 30 between the cover strips 26. For this purpose, the cover strips 26 are fixedly connected to the sheath 16 in the direction of the two longitudinal edges 18 and can be lifted up like a pocket in the direction of its two adjacent edge regions, overlapping at the edges and allowing the absorbent body 30 to be accommodated in the diaper so as to cover the diaper.

[0020] A suitable absorbent material for the absorbent body 30 is a fluid-permeable gauze sheath that contains cellulose flakes on the inside of the absorbent body 30 and serves to absorb fluids (typically the excrement of a diaper user). Further details regarding the construction of such diapers are described in DE 10 2019 006 683 A1.

[0021] The substrate 10, which is formed as a film from a given plastic material, has a low melting point, which allows it to avoid adhesion by thermal bonding to other components, such as the components of the diaper in the form of the two closure tabs 22. The melting temperature of the other components in the form of the respective closure tabs 22 on the diaper is preferably higher than the melting temperature of the substrate 10 of the adhesive fastener made of a film material.

[0022] As further shown in FIG. 1, the film thickness of the substrate 10 is between 0.30 mm and 0.36 mm, and the melt temperature is about 70° C. This allows the peel adhesion of the removable adhesive closure member to the top side of the diaper or loop or ringlet material as an additional adhesive fastener (not shown) to average 2.34 N / cm 2 Instead of additional adhesive fasteners, the closure system can also be formed by loops or ringlets of material in the surface material of the diaper. Overall, diapers constructed in this manner are largely capable of biologically degrading after use and / or are made from bio-based materials.

[0023] The verification of the elongation at break and / or the breaking strength resulted in the following properties: The measurements were carried out along the entire width of the film-like adhesive fastener (hook and loop film) by the so-called Zwicki™ from Zwick / Roell The strips measured in this way had a length of 200 mm and a width of 20 mm. Polylactic acid (PLA) material, as sold under the trade name Inzea™, used throughout the adhesive fastener has been shown to have elongations at break of over 100% and strengths at break of over 40N, while PLA material sold under the trade name ArcBio™ has been shown to have elongations at break of over 15% and strengths at break of over 90N.

[0024] Using a Kruss drop shape analyzer, free surface energy measurements using two liquids (water and diiodomethane) on the backside of the adhesive fastener (right, center, and left) showed a dispersion fraction of >39 mJ / m for Inzea™. 2 A polar fraction of 0.01 mJ / m was obtained. When the material was ArcBio™, the dispersive fraction was >39 mJ / m 2 and the polar fraction is 6 mJ / m 2 That's all.

[0025] Occlusion thickness measurements were performed with a Wolf Measurement Technologies DM2000 thickness measurement device and demonstrated a thickness of, for example, about 0.360 mm for the Inzea™ adhesive fasteners and about 0.343 mm for the ArcBio™ adhesive fasteners.

[0026] Measurement of the heat distortion resistance according to DIN EN ISO 75 [HDT 0.45 MPA (B)] demonstrated HDT values ​​of approximately 50°C for the Inzea™ adhesive fasteners and approximately 96°C for the ArcBio™ adhesive fasteners.

Claims

1. 1. An adhesive fastener comprising at least one plastic material having a plurality of hook means integrally connected to a substrate (10), each hook means being in the form of a stem (14) with a head portion (12), the adhesive fastener projecting from the substrate (10) being characterised in that at least a portion of the plastic material used is biodegradable.

2. 2. The adhesive fastener of claim 1, wherein the biodegradable plastic material is polycaprolactone (PCL), polybutyrate (PBAT), or polybutylene succinate (PBS).

3. 3. An adhesive fastener according to claim 1 or 2, in which the biodegradable plastic material consists of polylactic acid (PLA), or polyhydroxyalkanoate (PHA), or thermoplastic elastomer (TPS), or starch.

4. 4. The adhesive fastener according to claim 1, wherein the substrate (10) is in the form of a film of meltable plastic material, allowing an adhesive-free connection by thermal bonding to other components of the diaper.

5. An adhesive fastener according to any one of claims 1 to 4, characterized in that the melting temperature of the other component, which is the closure tab (22) on the diaper, is higher than the melting temperature of the substrate (10) made of a film material.

6. A diaper comprising a production material constructed from at least 85% biodegradable materials and having at least one adhesive fastener according to claims 1-5.

7. 7. The diaper of claim 6, further comprising a closure tab, the closure tab having at least one adhesive fastener according to any one of claims 1 to 5.

8. 8. The diaper of claim 7, wherein the adhesive fastener of any one of claims 1 to 5 is permanently attached to the closure tab (22) by thermal bonding without the use of adhesive.

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