EP1600399B1 - Plastic bag for bulk material - Google Patents

Abstract

The sack (1) has a multilayer overlap region with inner and outer plastic layers, at least one venting device (10) with at least one first venting opening (11) in the inner plastic layer of the overlap region (5) and at least one second venting opening (12) in the outer plastic layer of the overlap region, whereby the first and second venting openings are not aligned. When filled the sack can be stacked so that the first opening(s) is higher than the second opening(s), whereby a venting channel is formed between the openings in the overlap region.

Description

The invention relates to a bag filled with a bulk material of plastic film according to the preamble of claim 1.

If a powdered bulk material is filled in a plastic bag, after the hermetic sealing of the bag by segregation of the material-air mixture forms after some time an air bubble in the bag. If such sacks are stacked on top of each other, they can burst or tear relatively easily due to the air bubbles that are subjected to pressure. In addition, the trapped air affects the stackability on pallets.

To solve this problem, it is known to provide the bags with venting devices (see eg EP 768,245 ).

Furthermore, from the DE 31 45 259 A1 a plastic bag for bulk materials is known in which a bottom is provided with a row of holes, so that air can escape from the bag. The row of holes is closed by means of a cover sheet, which consists of an air-permeable filter material to retain the bulk material in the sack. Such a venting of the bag is still possible even after filling the bag, but the bag is not sufficiently protected against the ingress of moisture from the outside into the bag.

A further development of this idea shows the DE 43 03 894 C2 according to which a tube is first formed from a flat web consisting of one or more layers is, which has a moisture-proof, thermoplastic layer which is provided with a parallel and spaced from the longitudinal edges extending ventilation area. In the course of tube formation from the flat webs, the longitudinal seam initially remains at least partially unlocked and the open region of the longitudinal seam of the thermoplastic layer is provided with a plastifiable bonding material whose melting point is below that of the thermoplastic, moisture-proof layer. This arrangement has proven itself, but it requires a later closing of the bag after venting to realize a sufficient tightness.

From the US PS3302859 In addition, a bag is known, in the production of which also from a one or more layers existing flat web first a tube is formed. In the hose formation from the flat webs, the longitudinal seam assembly is formed as a double seam of two mutually parallel seams and the inner and the outer plastic layer in the overlap region between the two seams are each provided with perforations that are not aligned, so that on the one hand a vent is given and on the other hand, water should not enter directly from outside through the perforations into the interior of the bag. In this way, although a satisfactory ventilation is realized. But against the ingress of moisture from the outside, the bag interior is still not sufficiently secured. A comparable prior art shows the AT 335 898 A ,

The invention has the object to further develop the generic bag such that a good ventilation on the one hand and on the other hand a good protection against ingress of moisture from the outside is ensured in the bag interior without the bag in a further step must still be hermetically sealed after venting.

The invention solves this problem by the subject matter of claim 1.

Thereafter, the bag in the filled state is stackable so that the at least one first vent opening in the inner plastic layer of the overlap region offset in height is higher to the at least one second vent opening in the outer plastic layer of the overlap region, wherein between the vent openings in the overlap region, a vent channel is formed.

In this way, air can still escape from the filled bag even after it has been filled and closed, but it is ensured that moisture is hindered as much as possible from penetrating into the bag interior, because in the stacked state of the bags it would have to overcome the height difference between these openings, as it were is almost impossible.

The bag is stackable in such a way that the overlapping region is arranged on the top side of the bag and extends into the region of the transverse sides in which the transverse seams lie. The first vent openings are arranged in the stacking position of the bag on the upper side and the second vent openings on at least one or preferably both of the transverse sides with the transverse seams. In this way, the invention can be realized structurally simple.

The second vents are in the stack position by more than 15%, in particular more than 30% of the bag height a lower than the first vents, but at least below the material level in the bag. The greater the height offset, the better it protects against the ingress of moisture. It is particularly advantageous if the second vent openings are arranged in the vicinity of the transverse seams or at these, so that the height offset to the first vent openings is as large as possible.

A further advantageous possibility for achieving a sealing effect of the venting device, which at the same time is intended to prevent the ingress of moisture, can be realized by the use of moisture-reactive substances. These are preferably to be introduced into the channel-like overlapping region of the two films in the area of the venting device. Without moisture from the outside, the air can escape unhindered from the bag. As soon as external influences cause moisture penetrates into the venting device, this substance reacts with the water and leads to a sealing of the plastic films, whereby a moisture-impermeable seal is formed. This can, for example, by the swelling of this substance, a catalytically caused by the moisture bonding or the like. respectively.

As a variant of these moisture-reactive substances, substances such as e.g. Gels, greases or other substances with comparable properties can be used, through which trapped air can rise under pressure, but externally penetrating moisture is effectively rejected. In this way, a substance is introduced into the area of the venting device which closes off the venting duct and allows air to pass out from inside and then closes again as readily as possible, whereby moisture is effectively prevented from penetrating into the interior of the bag by the venting duct.

Further advantageous embodiments can be found in the remaining subclaims.

Fig. 1

eine perspektivische Ansicht eines ersten erfindungsgemäßen Sackes;

Fig. 2

einen Schnitt durch die Linie A-A der Fig. 1;

Fig. 3

einen Schnitt durch die Linie B-B der Fig. 1;

Fig. 4

eine perspektivische Ansicht eines zweiten erfindungsgemäßen Sackes;

Fig. 5

einen Schnitt durch die Linie B-B der Fig. 4;

Fig. 6

eine perspektivische Ansicht eines drittem erfindungsgemäßen Sackes;

Fig. 7

einen Schnitt durch die Linie B-B der Fig. 6; und

Fig. 8

einen Schnitt durch einen vierten erfindungsgemäßen Sack.

The invention will be explained in more detail with reference to the drawing with reference to embodiments. It shows:

Fig. 1

a perspective view of a first bag according to the invention;

Fig. 2

a section through the line AA the Fig. 1 ;

Fig. 3

a section through the line BB the Fig. 1 ;

Fig. 4

a perspective view of a second bag according to the invention;

Fig. 5

a section through the line BB the Fig. 4 ;

Fig. 6

a perspective view of a third bag according to the invention;

Fig. 7

a section through the line BB the Fig. 6 ; and

Fig. 8

a section through a fourth bag according to the invention.

Fig. 1 to 3 show a first embodiment of a filled with a bulk packaging container in the form of a bag. 1

The bag 1 is made of a plastic film 2, which was formed by means of a longitudinal seam arrangement of two mutually preferably parallel longitudinal seams 3, 4 to form a tube. The bag therefore has an overlap region 5 made of an inner plastic layer 6 and an outer plastic layer 7.

Alternatively, it would also be conceivable to apply a second plastic layer in sections to a bag made of plastic manufactured in different ways or to attach it to the bag with several seams (not shown).

The two open ends of the plastic tube were joined together here in each case by means of one or more transverse seams 8, 9, in particular welded together.

When filling the bags with bulk material, it is advisable to cut lengths of predetermined length from an endless tube with longitudinal seams, then or to form one of the transverse seams 8 or to close the bag in this area, then to fill the open bag and finally that remaining open end with the other transverse seam 9 to close.

For venting the bag interior after filling with the bulk material and closing the bag by a mating connection of the material layers, a venting device 10 is provided which has at least one or more first vent opening (s) 11 in the inner plastic layer 6 of the overlap region 5 and at least one or a plurality of second vent opening (s) 12 in the outer plastic layer 7 of the channel-like overlap region 5 or of the venting channel between the vent openings. The vent openings 11, 12 may be formed, for example, as perforations, as slots or as punched outs of other geometry.

The first and second vent openings 11, 12 are not aligned with each other and the first vent opening (s) 11 in the inner plastic layer 6 in the filled state of the bag have a different height - based on an arrangement in the stackable Location of Fig. 2 , wherein the overlapping region 5 is arranged in this arrangement on the top 13 of the bag and extends into the region of the transverse sides 14, 15, in which the transverse seams 8, 9 lie - as the second vent opening (s) 12 in the outer plastic layer 7th

In order to realize this height offset of the first and second vent openings 11, 12, the first vent openings 11 in the in Fig. 2 shown stacking position of the bag on the upper side 13 and the second vent openings 12 here only or substantially at least one or preferably on both of the transverse sides 14, 15 with the transverse seams 8, 9 arranged. According to the illustrated embodiments, the first vents are concentrated in the middle of the overlap region between the transverse sides 14, 15 with the transverse seams 8, 9 and extend over less than 50%, in particular 30% of the length of the top 13. Such is not only a height offset realized, which prevents intrusion but also created over the prior art, a much more effective labyrinthine arrangement, which also counteracts the ingress of moisture.

The embodiments of Fig. 4 and 5 and 6 and 7 differ from the embodiments of the Fig. 1 to 3 in that the first ( Fig. 4 and 5 ) and (not shown) / or the second ( Fig. 6 and 7 ) Vent openings 11, 12 inside and / or outside of labels or cover sheets 16, 17, 18 are covered by a material such as a membrane, the passage of air and moisture out of the bag inside to the outside, but substantially no intrusion of Moisture allowed from the outside to the interior of the bag. In this way, the penetration of moisture is even more reliably avoided.

An analogous effect is achieved by a fleece 19 (FIG. FIG. 8 ) achievable. The nonwoven 19 may also be arranged in the overlap region between the longitudinal seams and in particular also extend into the area of the first and / or second vent openings 11, 12 or beyond.

reference numeral

bag

1

Plastic film

2

longitudinal seams

3, 4

overlap area

5

inner plastic layer

6

outer plastic layer

7

cross stitching

8.9

vent

10

first vent opening (s)

11

second vent opening (s)

12

top

13

transverse sides

14, 15

label

16, 17, 18

fleece

19

Claims (8)

1. Plastic bag for bulk material, comprising:

   a) at least in sections, a multi-layer overlapping region (5) made of an inner plastic layer (6) and an outer plastic layer (7),

   b) at least one venting device (10) having one or more first vent opening(s) (11) in the inner plastic layer (5) of the overlapping region (5) and one or more second vent opening(s) (12) in the outer plastic layer (7) of the overlapping region (5),

   c) wherein the first and second vent openings (11, 12) are not in mutual alignment,

   d) wherein a vent passage is formed in the overlapping region between the vent openings (11, 12),

   e) and wherein the bag (1) is made of a plastic film (2) in the shape of a tube which is joined in the overlapping region (5) of the tube by means of a longitudinal seam arrangement comprising two parallel longitudinal seams (3, 4), the two open ends of the plastic tube being joined by means of one or more transverse seams (8, 9),

   f) wherein the bag can be stacked such that the overlapping region (5) is located on the top side (13) of the bag and extends into the region of the lateral sides (14, 15) where the transverse seams (8, 9) are located,
   characterised in that

   g) in the filled state, the bag (1) can be stacked such that each first vent opening (11) in the inner plastic layer (6) of the overlapping region (5) is vertically offset against and lying higher than the one or more vent opening(s) (12) in the outer plastic layer (7) of the overlapping region (5),

   h) so that in the stacked position of the bag the first vent openings (11) are located on the top side (13) and the second vent openings (12) are located on at least one and preferably on both of the lateral sides (14, 15) with the transverse seams (8, 9), and

   i) so that in the stacked position the second vent openings (12) are placed lower than the first vent openings (11) by more than 15% of the bag height a.
2. Bag according to claim 1, characterised in that in the stacked position the second vent openings (12) are placed lower than the first vent openings (11) by more than 30% of the bag height a.
3. Bag according to any of the preceding claims, characterised in that the first and/or the second vent openings (11, 12) is/are covered by labels (16, 17, 18) made of a material which allows air and moisture to escape from the interior of the bag but essentially does not allow any outside moisture to penetrate into the interior of the bag.
4. Bag according to claim 3, characterised in that the first and/or the second vent openings (11, 12) is/are covered by a web (19).
5. Bag according to claim 4, characterised in that the web (19) is placed in the overlapping region (5) between the longitudinal seams and in particular extends into or beyond the region of the first and/or second vent openings.
6. Bag according to any of the preceding claims, characterised in that the vent openings (11, 12) comprise perforations, slots or hole patterns of different geometry.
7. Bag according to any of the preceding claims, characterised in that a moisture-reactive substance which, by swelling or agglutination, seals the vent passage, which was originally open at least partially to let air escape, if moisture enters is installed into the overlapping region (5) in the region of the venting device.
8. Bag according to any of the preceding claims, characterised in that a substance which seals the vent passage, lets air escape from the interior and then once again seals is installed into the region of the venting device, thereby preventing the penetration of moisture into the bag interior through the vent passage.

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