WELDABLE SPUNBOND FABRIC, METHOD OF MAKING SAME, AND PACKAGING MADE THEREFROM

Abstract

A weldable spun-bonded nonwoven has endless filaments of a thermoplastic plastic that contain at least 3 wt % of at least one filler to improve the weldability of the spun-bonded nonwoven. In addition the endless filaments are monocomponent filaments.

Claims

1. A weldable spun-bonded nonwoven, wherein the spun-bonded nonwoven has endless filaments of a thermoplastic plastic, the endless filaments contain at least 3 wt % of at least one filler to improve the weldability of the spun-bonded nonwoven, and the endless filaments are monocomponent filaments.

2. A weldable spun-bonded nonwoven, wherein the spun-bonded nonwoven contains endless filaments of a thermoplastic plastic, the endless filaments are multicomponent filaments, and at least one component of these endless filaments contains at least 3 wt % of at least one filler to improve the weldability of the spun-bonded nonwoven by reducing the welding temperature in thermal welding of the spun-bonded nonwoven.

3. The weldable spun-bonded nonwoven according to one of claims 2, wherein the one component of the endless filaments has 4 to 25 wt % of the filler.

4. The weldable spun-bonded nonwoven according to 2, wherein the filler is a metal salt, preferably an alkaline earth metal salt.

5. The weldable spun-bonded nonwoven according to claim 2, wherein a first plastic component present on the surface of the multicomponent filaments or bicomponent filaments has the same or a lower melting point than a second plastic component of the filaments and the filler is contained at least in the first same- or lower-melting-point plastic component.

6. The weldable spun-bonded nonwoven according to claim 5, wherein the multicomponent filaments are bicomponent filaments that have a core/sheath configuration and the sheath constitutes the same- or lower-melting-point plastic component of the filament.

7. The weldable spun-bonded nonwoven according to claim 6, wherein the filler is present at least in the sheath of the bicomponent filaments filaments.

8. The weldable spun-bonded nonwoven according to claim 6, wherein a mass ratio of the first, same- or lower-melting-point plastic component to the second, higher-melting-point plastic component is 10:90 to 35:65.

9. The weldable spun-bonded nonwoven according to claim 1, wherein the spun-bonded nonwoven is a calendered spun-bonded nonwoven and at least one surface of the spun-bonded nonwoven is calendered smooth.

10. A method of making a weldable spun-bonded nonwoven or packaging spun-bonded nonwoven according to claim 1, wherein endless filaments are spun by a spinneret, are cooled in a cooler, and then stretched by a stretcher and are then deposited on a deposition apparatus to produce the spun-bonded nonwoven.

11. The method according to claim 10, wherein the spun-bonded nonwoven is pressed with a calender having an embossing surface of 10 to 90% and preferably 18 to 30% and wherein preferably the embossing depth calender engraving 0.1 to 0.6 mm, preferably 0.2 to 0.4 mm.

12. The method according to claim 10, wherein the number of engraved points of the calender is greater than 30/cm.sup.2.

13. A package for containing pourable and/or free-flowing products such as cement and the like, having at least one spun-bonded nonwoven or packaging spun-bonded nonwoven according to claim 1, wherein the spun-bonded nonwoven/packaging spun-bonded nonwoven forms the package wall and/or is a component of the package wall and wherein sections of the spun-bonded nonwoven/packaging spun-bonded nonwoven in the side wall region and/or at the bottom and/or at the top of the package or the package wall are welded to one another.

14. The package according to claim 13, wherein the spun-bonded nonwoven/packaging spun-bonded nonwoven is a component of a package wall laminate and wherein the laminate preferably also contains at least one film, preferably a plastic film.

15. The package according to claim 14, wherein the film or plastic film is provided on an inner face of the package wall.

16. The package according to claim 13, wherein the side wall of the package contains at least one spun-bonded nonwoven, the spun-bonded nonwoven contains bicomponent filaments with a core/sheath configuration and the mass ratio of the core to the sheath is 10:90 to 35:65.

17. The package according to claim 13, wherein at least one top wall and/or at least one flat top wall is a component of the package wall, wherein the top wall contains at least one spun-bonded nonwoven, in particular according to one of claims 2 through 9, wherein the spun-bonded nonwoven contains bicomponent filaments with a core/sheath configuration and wherein the mass ratio of the core to the sheath is 35:65 to 50:50.

18. The package according to claim 13, wherein at least one bottom wall and/or at least one flat bottom wall is a component of the package wall, wherein the bottom wall contains at least one spun-bonded nonwoven, in particular according to one of claims 2 through 9, wherein the spun-bonded nonwoven contains bicomponent filaments with a core/sheath configuration and wherein the mass ratio of the core to the sheath is 35:65 to 50:50, preferably 40:60 to 45:55.

19. A spun-bonded nonwoven, wherein the spun-bonded nonwoven is formed wholly of endless bicomponent filaments of at least one thermoplastic plastic and each having a core and a sheath, and the sheaths each contain at least 3 wt % of at least one filler that lowers the melting point of the sheath below that of the cores.

Description

[0041] The invention will be explained in greater detail below in conjunction with drawings that depict only one exemplary embodiment. In the drawings:

[0042] FIG. 1 is a schematic, perspective view of a package according to the invention in the form of a bag,

[0043] FIG. 2 is a schematic vertical section through am apparatus for carrying out a method of making a weldable spun-bonded nonwoven or packaging spun-bonded nonwoven according to the invention, and

[0044] FIG. 3 is a schematic cross-section through a bicomponent filament of a spun-bonded nonwoven or packaging spun-bonded nonwoven

[0045] a) as a component of the package wall in the side wall region of the packaging bag and

[0046] b) as a component of the package wall of the bottom wall and/or the top wall of the packaging bag.

[0047] FIG. 1 shows a package according to the invention in the form of a packaging bag 1 for bulk materials, in particular for cement.

[0048] The package wall of this packaging bag 1 contains weldable spun-bonded nonwovens 2 according to the invention. These spun-bonded nonwovens 2 or packaging spun-bonded nonwovens are of endless filaments 3 of a thermoplastic plastic. The endless filaments 3 contain at least 3 wt % of a filler 4 in the form of calcium carbonate to improve the weldability of the filaments and of the spun-bonded nonwoven 2 and in particular to reduce the welding temperature during thermal welding of the filaments or of the spun-bonded nonwoven 2.

[0049] The packaging bag 1 shown in FIG. 1 has a side wall 5 of a spun-bonded nonwoven according to the invention that has been welded at its side edges 6 into a tube, so to speak. A flat bottom wall 7 in the form of a spun-bonded nonwoven 2 according to the invention is positioned at the bottom of the packaging bag 1 and is welded to the side wall 5 of the packaging bag 1. A flat top wall 8 in the form of a spun-bonded nonwoven 2 according to the invention is likewise positioned at the top of the packaging bag 1 and welded to the side wall 5. On an inner face of the package wall of the packaging bag 1, an additional plastic film can be provided, but this is not shown in the embodiment according to FIG. 1. The spun-bonded nonwovens used for the side wall 5, the bottom wall 7, and the top wall 8 of the packaging bag 1 are preferably, and in this embodiment, of bicomponent filaments with a core/sheath configuration (also see FIG. 3). Of the two plastic components of these bicomponent filaments, the lower-melting-point plastic component is the sheath 9 and the higher-melting-point plastic component is the core 10. the filler 4 in the form of calcium carbonate is preferably, and in this embodiment, only contained in the sheath 9 of the bicomponent filaments.

[0050] FIG. 2 shows a particularly preferred apparatus for manufacturing the spun nonwovens 2 (spun-bonded nonwovens) according to the invention. The endless filaments 3 in this case are first spun by a spinneret 11 and are then conveyed through a monomer aspirator 12. Then the endless filaments 3 are chilled in the cooler 13. The cooler 13 preferably, and in this embodiment, has two compartments 14, 15 one above another or one after another in the filament flow direction from which cooling air with different temperatures is introduced into the filament flow chamber. After the cooler 13, the endless filaments 3 travel into an intermediate conduit 16 that converges in the filament flow direction. This intermediate conduit 16 is followed by a pull-down conduit 17 of the stretcher 18. This design serves to stretch the endless filaments 3. The endless filaments 3 emerging from the pull-down conduit 17 then preferably, and in this embodiment, pass through two diffusors 19, 20 one above the other or one after another in the filament flow direction. In a recommended embodiment, and here, an ambient air entry gap 25 is provided between the diffusors 19, 20 for drawing in ambient air. Advantageously, and in this embodiment, the endless filaments 3 are then deposited on a mesh belt 21 to form the spun-bonded nonwoven 2. The spun-bonded nonwoven 2 is advanced in the machine direction M by the mesh deposition belt 21.

[0051] Preferably, and in this embodiment, the spun-bonded nonwoven 2 is calendered and prehardened/hardened by a calender 22.

[0052] According to one variant, a calender roller 23 is provided with an engraving, not shown in detail, and a calender roller 24 of the calender 22 that cooperates with and is works with it is preferably, and in this embodiment, equipped with a smooth surface. A spun-bonded nonwoven 2 made in the above-explained manner can be simply and easily used for a package wall (side wall 5 and/or bottom wall 7 and/or top wall 8) of the packaging bag 1.

[0053] FIG. 3 shows bicomponent filaments for a weldable spun-bonded nonwoven 2 according to the invention. In the embodiment of the bicomponent filaments shown in FIG. 3a, the percentage of the core 10 is higher in comparison to the sheath 9. In the bicomponent filaments according to FIG. 3, the filler in the form of calcium carbonate is contained only in the sheath 9 that corresponds to the lower-melting-point plastic component. The bicomponent filaments according to FIG. 3a are primarily suitable for spun-bonded nonwovens 2 that form the side wall 5 of a packaging bag 1.

[0054] By contrast, the bicomponent filaments according to FIG. 3b have a significantly higher percentage of sheath 9 of the lower-melting-point plastic component. Here, too, the filler preferably, and in this embodiment, is completely contained in the sheath 9. The bicomponent filaments according to FIG. 3b are primarily suitable for spun-bonded nonwovens 2 or spun-bonded nonwoven regions that must be welded. The sheath 9 with the lower-melting-point plastic component provides enough welding material for this purpose. Welding is preferably carried out in that only or mainly the sheath 9 melts and is welded.

[0055] Consequently, the bicomponent filaments according to FIG. 3b are primarily suitable for the bottom wall 7 and/or the top wall 8 that is to be welded of a packaging bag according to the invention 1.

[0056] The mass ratio of the lower-melting-point plastic component (sheath 9) to the higher-melting-point plastic component (core 10) may be 20:80 in the embodiment according to FIG. 3a. By contrast, in this embodiment according to FIG. 3b, the mass ratio of the lower-melting-point plastic component 5 (sheath 9) to the higher-melting-point plastic component (core 10) is 40:60.