MULTILAYER WRAPPER FILM FOR HYGIENE PRODUCT

Abstract

A multilayer wrapper film for a hygiene product has a first outer layer, a second outer layer, and a pressure-sensitive adhesive layer between the first outer layer and the second outer layer and forming therewith respective adhesive bonds. The adhesive bond between the pressure-sensitive adhesive layer and the first outer layer is stronger than the adhesive bond between the pressure-sensitive adhesive layer and the second outer layer. An overall thickness of the first and second outer layers with the pressure-sensitive adhesive layer arranged therebetween is between 20 m and 80 m.

Claims

1. A multilayer wrapper film for a hygiene product, the film comprising: a first or upper outer layer; a second or lower outer layer; and a pressure-sensitive adhesive layer between the first outer layer and the second outer layer and forming therewith respective adhesive bonds, the adhesive bond between the pressure-sensitive adhesive layer and the first outer layer being stronger than the adhesive bond between the pressure-sensitive adhesive layer and the second outer layer, an overall thickness of the first and second outer layers with the pressure-sensitive adhesive layer arranged therebetween being between 20 m and 80 m.

2. The multilayer wrapper film defined in claim 1, wherein the second outer layer has a release sublayer that lies against the pressure-sensitive adhesive layer.

3. The multilayer wrapper film defined in claim 1, wherein a thickness of the first outer layer and the second outer layer together is between 5 m and 30 m and a thickness of the pressure-sensitive adhesive layer is between 5 m and 25 m.

4. The multilayer wrapper film defined in claim 1, wherein the first outer layer, the second outer layer and the pressure-sensitive adhesive layer are coextruded.

5. The multilayer wrapper film defined in claim 1, wherein the pressure-sensitive adhesive layer is formed of a styrene block copolymer base.

6. The multilayer wrapper film defined in claim 5 wherein the copolymer base is a styrene-isoprene-styrene block copolymer base.

7. The multilayer wrapper film defined in claim 1, wherein the pressure-sensitive adhesive layer is thermoplastic and the first outer layer and the second outer layer are produced separately and are laminated using the pressure-sensitive adhesive layer as a hot-melt adhesive.

8. The multilayer wrapper film defined in claim 7, wherein the pressure-sensitive adhesive layer has an acrylate base.

9. The multilayer wrapper film defined in claim 1, wherein the first outer layer and the second outer layer each have a polyolefin as a polymeric main constituent.

10. The multilayer wrapper film defined in claim 9, wherein the polyolefin is polyethylene.

11. The multilayer wrapper film defined in claim 1, wherein at least the first outer layer is stretched.

12. The multilayer wrapper film defined in claim 11, wherein the first outer layer contains filler materials and has breathable pores formed by stretching.

13. The multilayer wrapper film defined in claim 1, further comprising: a sanitary pad having an outer periphery; and a nonrelease bond between a rear face of the pad and an outer face of the first outer layer.

14. The multilayer wrapper film defined in claim 13, wherein the pad bonded over its entire surface area within the periphery to the first outer layer so that the first outer layer forms a rear surface of the sanitary napkin.

15. The multilayer wrapper film defined in claim 13, wherein a rear surface over between 20% and 80% of a surface area of the sanitary napkin within its periphery in a flattened state.

16. The multilayer wrapper film defined in claim 13, wherein the rear face of the pad and the outer face of the first layer are secured together by the nonrelease bond along two strips.

17. The multilayer wrapper film defined in claim 13, wherein the first outer layer has a tear line at an outer periphery of the nonrelease bond.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0052] The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

[0053] FIG. 1 is a top view of a flattened sanitary napkin on a section of a wrapper film during a first production step;

[0054] FIG. 2 is a perspective view of the sanitary napkin wrapped individually in the wrapper film;

[0055] FIG. 3a is a large-scale longitudinal section along line IIIa-IIIa of FIG. 1;

[0056] FIG. 3b is a view like FIG. 3a, but showing the assembly after the package has been unfolded and the sanitary napkin has been pulled away from the wrapper film;

[0057] FIG. 4a shows the arrangement as to FIG. 3a in an alternative embodiment; and

[0058] FIG. 4b shows the arrangement of FIG. 4a with the sanitary napkin pulled away from the wrapper film as in FIG. 3b.

SPECIFIC DESCRIPTION OF THE INVENTION

[0059] As seen in FIG. 1 a dumbbell-shaped sanitary napkin 1 in a flattened-out state lies atop a rectangular section of wrapper film 2 that actually is part of a long strip of the film extending in a production direction lying in the view plane and perpendicular to a longitudinal direction L of the napkin 1.

[0060] To allow a sanitary napkin 1 to be fastened in the crotch area of a pair of underpants, the underside of the sanitary napkin is provided as shown in FIG. 1 with a pair of adhesive regions 3 containing a pressure-sensitive adhesive 4. The regions 3 are parallel strips parallel to one another along the longitudinal direction L of the napkin 1.

[0061] The napkin 1 can also be provided in a central zone thereof with unillustrated lateral wings that are first folded over toward the top and that also have adhesive regions. Within the scope of such an unillustrated embodiment a separate cover is then required for the wings that are folded over toward the top.

[0062] FIG. 2 shows the napkin 1 packaged individually with a wrapper film 2 and made by folding the flattened arrangement of FIG. 1 together along fold lines 5 extending transverse to the longitudinal direction L into a C-shape, so that the longitudinally opposite ends of the napkin 1 are in a central zone defined between the fold lines 5.

[0063] According to FIG. 3a, the wrapper film 2 has several layers and comprises a first or upper outer layer 6, a second or lower outer layer 7, and the layer 4 of pressure-sensitive adhesive between the first outer layer 6 and second outer layer 7. All the layers 4, 6, and 7 are in surface contact with each other with no gaps or voids.

[0064] The napkin 1 on the wrapper film 2 comprises a pad 8 itself formed by a plurality of nonwoven layers under an unillustrated fluid-permeable top cover layer. The napkin 1 further has a backing sublayer 15 that preferably has breathable properties but is watertight.

[0065] The napkin 1 is sealed to the first outer layer 6 by a nonrelease adhesive layer 10 forming a rear surface 9 of the back sublayer 15 of the napkin 1. The nonrelease adhesive layer 10 is applied, according to the embodiment of FIG. 3a, within a tear line 11 has already been formed in the first outer layer 6 by punching or by a laser and that has dumbbell shape conforming to that of the outer periphery of the napkin 1. This line is optional. Alternatively, the first outer layer may also be designed to easily tear away from the rest of the wrapper film 2 as the napkin 1 is pulled away.

[0066] According to the invention, the adhesive bond of the adhesive layer 4 to the first outer layer 6 is stronger than the adhesive bond between the adhesive layer 4 and the second outer layer 7. Thus when the pad 8 is pulled up, it will take the layers 10, 6, and 4 with them and leave the layer 7 behind. as shown in FIG. 3b.

[0067] In the embodiment shown, the second outer layer has two sublayers, namely a base sublayer 12 and, bordering the adhesive layer 4, a release sublayer 13 that has a particularly weak adhesive bond relative to the adhesive layer 4 and that ensures separation between the layers 4 and 7. In the embodiment shown, the first outer layer 6 is formed by only one film layer; however, a multilayer embodiment is also possible.

[0068] In the embodiment shown, the thickness of the base sublayer 12 and the first outer layer 6 is within a range of 5 m and 20 m, for example approximately 13 m, and it is made of a polyolefin, preferably polyethylene (PE), so that in the folded state according to FIG. 2, the first outer layer 6 can be bonded to the base sublayer 12 of the second outer layer 7 by a thermal weld 14, allowing a separate adhesive strip for sealing the package according to FIG. 2 to be dispensed with.

[0069] When the napkin 1 is pulled away from the wrapper film 2, according to FIG. 3b, the first outer layer 6 with the adhesive layer 4 remains on the napkin 1 along the nonrelease adhesive layer 10, thereby producing the adhesive regions 3 shown in FIG. 1.

[0070] The adhesive regions 3 formed in this manner preferably extend across between 20% and 80% of the area of the napkin 1 in its flattened-out state (see FIG. 1).

[0071] The wrapper film 2 can be produced entirely by coextrusion or also by lamination. For example, the first outer layer 6 and the second outer layer 7 can be laminated together by the adhesive layer 4 if it is thermoplastic and is introduced in the molten state between the first outer layer 6 and the second outer layer 7. The adhesive layer 4 then serves during lamination as a hot-melt adhesive.

[0072] The adhesive layer 4 can be formed, for example, of a styrene-block copolymer base, in particular SIS, or with an acrylate base.

[0073] FIGS. 4a and 4b show an alternative embodiment of the invention, in which only the pad 8 of the napkin 1 is bonded by the nonrelease adhesive layer 10 to the first outer layer 6.

[0074] The pad 8 is preferably bonded across its entire surface area to the nonrelease adhesive layer 10, and later, when the napkin 1 is pulled away from the wrapper film 2, the first outer layer 6 remains attached to of the pad 8 by the nonrelease adhesive layer 10 and the adhesive layer 4 a rear surface 9 of the napkin 1, thereby enabling further simplification of the design.

[0075] To achieve breathability in an embodiment according to FIGS. 4a and 4b, the first outer layer 6 can be provided with filler materials, for example chalk, during its production, whereupon the first outer layer 6 is then stretched, forming breathable pores where the particles of filler material are located.

[0076] If the first outer layer 6 is laminated to the second outer layer 7, it is sufficient merely to stretch the first outer layer 6 prior to lamination. If, in contrast, the wrapper film 2 as a whole is produced by coextrusion, the entire coextrusion film must be subjected to a stretching process in order to provide the first outer layer 6 with breathable properties as described.