DE202021106637U1 - Paper valve sacks with non-taped barrier layer - Google Patents

Abstract

Paper valve bag with foil overlap for fine-grained bulk goods, such as cement, plaster, granulate, animal feed or similar,
- With a bottom, in particular a cross bottom, and
- with an upper part opposite the bottom, in which a valve tube for filling the paper sack is arranged,
- taking the paper bag out
i) an inner layer made of paper or paper composite, preferably highly air-permeable paper, and
ii) an outer layer made of paper or paper composite, and
iii) between the inner layer and the outer layer there is at least one barrier layer with two edges running essentially parallel to one another and from the bottom to the upper part, characterized in that the at least one barrier layer is not glued, its one edge in the overlapping area of the inner layer below the upper end of the Inner layer is arranged and its other edge overlaps the overlapping area of the inner layers.

Description

The invention relates to paper valve sacks with foil overlaps for fine-grained bulk goods such as cement, plaster, granules, animal feed or the like, with a bottom, for example a cross bottom, and with an upper part opposite the bottom, in which a valve tube for filling the paper sack is arranged, wherein the paper sack is formed from an inner layer and an outer layer, between which there is at least one barrier layer.

Such paper sacks are well known and are widely used commercially. The usual sizes are 5 kg content, 10 kg content, 20 kg content or 25 kg content.

A valve is provided for filling, which is incorporated into the upper part and which is placed on a filling nozzle for filling. The known valve bags consist of an inner and an outer layer of paper, between which a plastic film is inserted as a barrier layer.

It has turned out to be disadvantageous that an optimal filling of the paper sacks is not possible because the ventilation of the sacks is not sufficient.

With these sacks of the prior art, air can only escape with difficulty or not at all after the sacks have been filled. As a result, the throughput times for filling the sacks increase; it is not possible to fill the desired amount of filling material into the sack because there is still air in the sack during filling, so that an exact determination of the filling weight is not possible; the inflation of the sacks with air creates an overpressure in the sack, which is discharged through the valve when the sack is removed from the filling nozzle and part of the filling material can be expelled from the sack, which leads to contamination; and due to the poor ventilation, the sacks swell with air, which significantly impairs optimal palletizing, because after filling, however, they lie on the overlap and no more air can escape.

As prior art, for example, the WO 2006/092335 A1 be mentioned, in which the barrier layer is glued to the inner layer.

The object of the invention was to provide paper valve bags which, in comparison with the known prior art, have improved or at least equivalent venting properties, in particular during filling, and at least equivalent moisture protection. In addition, the paper valve sacks should have ecologically and economically advantageous properties, in particular they should dispense with the use of adhesive to attach the barrier layer.
The paper valve sacks should be able to be filled without problems, ie without the development of dust, sack bursting and with optimal filling times, whereby appropriate product protection of the filled sack should be guaranteed.

Further tasks will become apparent to those skilled in the art upon consideration of the following description and claims.

These and other objects, which will become apparent to a person skilled in the art upon consideration of the present description, are solved by the subject-matters presented in the independent claims.

Particularly advantageous and preferred objects emerge from the dependent claims and the following description.

The paper valve sacks of the present invention are preferably glued valve-bottom sacks made from a flat tube, both ends of which have been given a (hexagonal) bottom (cross-bottom) by means of cross-folding, shaping and gluing.

The exact design of the valve of the paper valve sacks according to the invention is not limited, but can be one of the types of valves known in the art, such as, but not limited to, fringed valves, pocket valves such as outer pocket valves, tube valves, polyethylene valves, polyethylene tube valves, multi-layer valves, filter valves, TV valves, be preferred selected from the group of valves consisting of reinforced valves, inner tube valves, outer pocket valves. In further preferred configurations, the valve is a tube valve protruding to the outside.

An essential feature of the present invention is that the barrier layer located between the inner and outer layers is not glued.

In the context of the present invention, “barrier layer” means a layer arranged between the inner and outer paper layers that is impermeable to air and in particular to moisture.

The barrier layer is sandwiched between the inner liner and the outer liner with its one end lying under the upper end of the inner liner in the overlap region of the inner liner ends.

The barrier layer can have a perforation (needling) on the side with which it is arranged under the upper inner layer. This can be a narrow strip, or a wider strip, but preferably extends from the edge of the short side of the barrier layer to the corresponding side edge of the paper valve bag.
A needling or perforation within the meaning of the present invention is an arrangement of punctures through a respective layer or ply in order to facilitate the escape of air during filling.

The needling of the barrier layer can have different structures, for example it can be designed in the form of a strip. Patterns such as checked patterns, striped patterns, wave patterns, etc. are also possible. An arrangement of several rows of holes is preferred, with the holes being equidistant from one another. The needling or perforation can be achieved using conventional methods known in the art.

The barrier layer of the paper valve sacks according to the invention is preferably designed in the form of a film which is arranged in a known manner between the inner layer and the outer layer on conventional paper sack manufacturing machines. The barrier layer can consist of the customary and known materials. In preferred embodiments, the material for the barrier layer is selected from the group of materials consisting of plastic, metal, paper and composite materials of these. Plastic is preferred as the material for the barrier layer, particularly preferably polyethylene, in particular HDPE.
Coated materials can also be used, for example a paper in which the coating can be, for example, a paint, plastic or metal, such as paper coated with polyethylene.

In embodiments of the paper valve sack according to the invention, the overlapping edge of the barrier layer is arranged under or just before the edge of the short side of the outer layer.

In the context of the present invention, reference is usually made to “the” barrier layer. Within the scope of the present invention, this formulation also includes multilayer barrier layers, for example in the form of two, three or four films arranged one on top of the other. It is preferred if the barrier layer has a single layer, in particular is a single-layer plastic film.

When speaking of an "edge" of a layer or the barrier layer in the context of the present invention, the edge that runs parallel to the side edges of the paper sack is meant, but not the upper edge or the lower edge that runs across the upper part or the ground level.

The paper valve bags according to the present invention can also ventilation devices, such as in EP 2 345 595 A1 described include.

Conventional adhesives, for example glue, dispersion adhesive, starch adhesives, polyvinyl acetate dispersion adhesives, hot-melt adhesives, etc., can be used for gluing the inner and/or outer layers. In certain variants of the present invention, however, it is also possible to connect the inner and/or outer layers by means of needling.
In the context of the present invention, cross (ver) bonding refers to the connection of the individual layers of a hose end to one another, as is also understood by GemPSI (Gemeinschaft Papiersackindustrie eV) and, unless otherwise stated, is also carried out accordingly as all-round bonding with point application.
Similarly, the gluing of the individual paper webs/layers to form a tube is referred to as longitudinal gluing.
The other terms are also understood as used by GemPSI.

Conventional materials can be used as the material for the paper sacks, preferably, but not limited to, kraft sack paper. Examples are machine smooth sack kraft, high stretch sack kraft, stretch sack kraft, lightweight crepe kraft sack, kraft crepe paper, wet strength kraft sack. In addition to the barrier layer, other flexible materials such as plastic films, fabrics, nonwovens, reinforced materials, laminated materials, impregnated paper can also be used in the production of the paper valve bags according to the invention.

The position of the filling device or the position of the valve is not relevant within the scope of the present invention and can be accommodated at will at one of the four corners of the sack, i.e. it can be arranged at the top or bottom and on the left or right.

The longitudinal seam of the paper valve sacks according to the invention can be arranged in the middle on the back, or offset to the left or right. In preferred embodiments, the longitudinal seam is located to the right of center when viewed from the rear; the side to the right of the longitudinal seam is then referred to as the "short side", and the side to the left of the seam as the "long side".

The paper valve sacks according to the invention can be used in particular for bulk goods, preferably fine-grained bulk goods such as food, animal feed, plaster, cement, granules, fertilizers, chemical base materials, etc., which occur as packaged goods in granular, granulated, powdered or chunky form.

In preferred embodiments, the paper valve sacks according to the invention are cross-bottom sacks.

The paper valve sacks of the present invention may also have other manufacturing features customary in the art such as, but not limited to, thumb recesses, closing aids, opening aids, carrying handles, sack windows, anti-slip treatments.
In addition to the needling of the barrier layer, the paper valve sacks according to the present invention can also have other needling, each of which represents an arrangement of punctures through the sack wall or individual layers thereof, in order to further facilitate the escape of air during the filling process.

The inner layer of the paper valve sacks according to the invention is normally not specially treated since it is not visible in use and does not need to be printed either. The congruent outer layer, on the other hand, may have been treated in such a way that it can be printed easily and also offers an attractive appearance.

In the case of the paper valve bags according to the present invention, the bag opposite the valve can optionally be provided with double beam gluing.

In the context of the present invention, it was surprisingly found that very advantageous effects can be achieved through the specific arrangement of the barrier layer.
The venting during the filling of the sack is nevertheless very effective and surprisingly the barrier layer does not distort despite the limited attachment area.

Another advantage is that the layers can be separated from each other relatively easily and completely, so that they can be disposed of separately according to recyclable materials. In addition, doing without adhesive in the barrier layer is advantageous from both an ecological and economic point of view. Furthermore, dispensing with gluing is simpler in terms of apparatus and requires less maintenance than gluing.

In addition, there are advantages in that the throughput times for filling the sacks are reduced; that there is less air in the sack due to the improved ventilation, which means that the desired quantity of filling material can be filled into the sack and the filling weight can be determined more precisely; there is no excess pressure in the sack because the sacks are no longer so inflated; and when the sack is ejected from the filling spout, the escape of filling material is avoided and there are no associated contaminations.

Also, after filling, air can still escape through the second lap (the long side of the barrier layer over its short and inner layer lap), allowing the bags to take their proper shape and good palletizing is possible.

In further embodiments of the paper valve sack according to the invention, at least part of the short side of the outer layer is needled or perforated, preferably by microneedling. This configuration makes it even easier for the air flowing out of the interior of the bag through the overlapping region of the barrier layer to escape from the bag. It is particularly preferred if this needling or perforation is the same as that of the barrier layer, ie barrier layer and outer layer are or were needled together.

In the context of the present invention, the edge of the long side of the inner layer overlaps the edge of the short side of the barrier layer. This protects the barrier layer in the region of its edge from air flowing out of the bag.
The special design of the paper valve sacks according to the invention ensures that the barrier layer surprisingly remains stationary despite the fact that no adhesive is used.

The design of the paper valve sacks according to the invention ensures that air can escape from the inside of the sack, which is particularly advantageous when the sack is being filled, but on the other hand no moisture can penetrate from the outside. By overlapping the barrier layer it is achieved that the overlapping part of the barrier layer is pushed up by an air flow coming from inside the sack, so that the air between it and the fixed part of the barrier layer can escape to the outside, but only during filling and no longer after filling the sack.

The inner layer of the paper valve sacks according to the invention is preferably made of a (highly) air-permeable paper through which the air can pass when the sack is filled. Then this air hits on the barrier layer, which, in addition to the perforations mentioned, can also be provided with small holes or slits in other places or entirely, so that it can let even more air through, but still remains moisture-repellent and water vapor-proof. This is possible within the scope of the present invention as an additional, preferred embodiment. Essentially, venting occurs through the barrier lap, which is not glued.

The inner layer of the paper valve sacks of the present invention is constructed so that one end of the inner length overlaps the other end. In the area of this overlap, the ends of the inner layer can be glued to one another, leaving an edge area free of glue, in order to arrange one end of the barrier layer there. Under the overlapping end of the inner length, the end of the barrier layer is placed but not glued.
The backsheet of the paper valve sacks of the present invention may be edge to edge, that is, so that the two ends of the backsheet abut, or so that one end of the outside length overlaps the other end. An overlap is preferred. In preferred configurations, the ends of the outer layer can be glued to one another in the region of this overlap.

In preferred embodiments of the present invention, the barrier layer is transversely bonded to the inner layer at the ends of the respective sack, which, however, in contrast to the prior art, does not cover the full cross-section throughout, but leaves several small areas unglued, preferably evenly distributed over the entire circumference , so that additional air can escape when the bag is filled. This can be done relatively easily in that, in contrast to the usual procedure for cross-gluing the barrier layer on the inner layer, only every second glue point is set.

For a sack with a filling quantity of 20 kg and a bulk density of 500 g/l, an overlap of the inner layer of about 1 cm to 4 cm is preferred, particularly preferably 2 cm; only an inner part of this overlap is glued, under the other part of the overlap one end of the barrier layer is positioned.

For a sack with a filling quantity of 20 kg and a bulk density of 500 g/l, an overlap of the outer layer of about 1 cm to 4 cm is preferred, particularly preferably 2 cm.
For a sack with a capacity of 20 kg and a bulk density of 500 g/l, an overlap of the barrier layer of 4 cm to 6 cm is preferred.
For such a sack, in some preferred embodiments, about 5 m ³ /h and more, more air flow during filling, can be achieved than with a standard sack according to the prior art.

In a preferred development of the present invention, the edges of the outer layer in the area of the bottom folds are continuously glued to one another in the longitudinal seam, and in the intermediate area of the longitudinal seam the gluing is only intermittent. If the sacks are to be filled with a high weight, it is preferable if the edges of the outer layer are additionally glued with a second longitudinal seam, with the edges of the outer layer also being continuously glued to one another in the area of the bottom folds and in the area of the second longitudinal seam lying in between the Bonding is also only intermittent, but the gaps in the bond are offset or arranged alternately to the gaps in the first intermittent bond.

The invention is explained in more detail below with reference to the figures. The figures are not necessarily true to scale and simplified. Thus, usual measures etc. familiar to the person skilled in the art are not necessarily shown (precise folding of the bases etc.) in order to make the figures easier to read.

Figure description:

1 shows a paper valve bag 1 with bottom 2 and top 3 schematically in the view of the back, ie the side on which the longitudinal seam is located. The bottom 2 and the upper part 3 are folded forwards in the sense of the view onto the back 4 of the valve bag 1 . The front side, which lies under the back side 4 and is congruent with it, cannot be seen. Such a paper sack is made from an inner layer of paper or paper composite with a rectangular shape and a congruent outer layer that is also made of paper or paper composite and is rectangular. In 1 the longitudinal seam is drawn to the right of center. One or more barrier layers 12, preferably a barrier layer 12, are inserted between the one-piece inner layer 11 and the likewise one-piece outer layer 13, the edges 8, 9 of which overlap. The inner layer 11 and the outer layer 13 are in 1 not shown for the sake of clarity.
The edges 8 and 9 of the barrier layer 12 or barrier layers 12 run parallel to the side edges 5 and 6 of the paper sack 1.
The right edge 9 of the barrier layer 12 is located under part of the long end of the innersheet 11 in an overlap area 7 (shown hatched). The left edge 8 of the barrier layer 12 overlaps the right edge 9 of the barrier layer 12 and the attachment area 7. A preferred embodiment of the present invention is illustrated by the dotted area 14, which is a perforated area of the barrier layer 12 and the backsheet 11. FIG. In 1 a valve 10 is also indicated. at 1 For the sake of clarity, the individual layers - inner layer 11, barrier layer 12 and outer layer 13 - are not shown.

2 is a sectional view taken along line AA in FIG 1 . It is illustrated how the individual layers - inner layer 11, barrier layer 12 and outer layer 13 - are arranged. The overlay area 7 where the barrier layer 12 is located under the long end of the innersheet 11 is also illustrated. In 2 is indicated by the large curly brackets, where the perforated area 14 extends from the left edge 9 of the barrier layer 12 to the right side edge 6 of the paper valve bag 1.
in the in 2 In the example illustrated, it is shown that the ends of the inner layer 11 overlap, part of which is glued via the adhesive bond 15 . In addition, the end of the long side of the inner layer overlaps the right edge 9 of the short side of the barrier layer 12 . The left edge 8 of the long side of the barrier layer 12 overlaps the right edge 9 and part of the needling area 7. In the figure, a variant is illustrated in which the left edge 8 of the long side of the barrier layer 12 to the right edge of the short side of the Outer layer 13 abuts. The left edge of the long side outer layer 13 overlaps with the right edge of the short side of the outer layer 13.

The various embodiments of the present invention, e.g. - but not exclusively - those of the various dependent claims can be combined with one another in any way, even if these combinations are not explicitly mentioned, provided that such combinations do not contradict one another.

Reference List

1

paper valve bag

2

floor

3

top

4

back

5

left side edge of the paper valve sack

6

right edge of the paper valve sack

7

Overlap area of inner layer edge over barrier layer edge

8th

left edge of barrier material

9

right edge of the barrier material

10

Valve

11

inner layer

12

barrier layer

13

outer layer

14

perforated area

15

bonding

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2006/092335 A1 [0006]
• EP 2345595 A1 [0022]

Claims (8)

Paper valve sack with foil overlap for fine-grained bulk goods, for example cement, plaster, granulate, animal feed or similar, - with a bottom, in particular a cross bottom, and - with an upper part opposite the bottom, in which a valve tube for filling the paper sack is arranged, - wherein the paper sack is formed from i) an inner layer made of paper or paper composite, preferably highly air-permeable paper, and ii) an outer layer made of paper or paper composite, and iii) between the inner layer and the outer layer at least one barrier layer with two substantially parallel to each other and from the bottom edges running towards the upper part, characterized in that the at least one barrier layer is not glued, its one edge is arranged in the overlapping area of the inner layer under the upper end of the inner layer and its other edge overlaps the overlapping area of the inner layers. paper valve bag claim 1 , characterized in that the short side of the outer layer is perforated, preferably by microneedling, the perforation particularly preferably extending to the right side edge of the paper valve sack. paper valve bag claim 1 or 2 , characterized in that the side of the barrier layer whose edge is arranged in the overlapping area of the inner layer below the upper end of the inner layer is perforated, preferably by microneedling, the perforation particularly preferably extending to the right side edge of the paper valve bag. Paper valve sack according to one of Claims 1 until 3 , characterized in that the overlapping edge of the barrier layer is located below or just before the edge of the short side of the backsheet. Paper valve sack according to one of Claims 1 until 4 , characterized in that the barrier layer is a film made of plastic, metal or optionally coated paper, preferably plastic, particularly preferably polyethylene, in particular HDPE. Paper valve sack according to one of Claims 1 until 5 , characterized in that in the case of the longitudinal seam the edges of the outer layer in the area of the bottom folds are continuously glued to one another and in the intermediate area of the longitudinal seam the gluing is only intermittent. Paper valve sack according to one of Claims 1 until 6 , characterized in that the longitudinal seam is not arranged centrally. Paper valve sack according to one of Claims 1 until 7 , characterized in that only every second adhesive point was set for the cross-gluing of the barrier layer on the inner layer.

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