FI65047B - PLASTSAECK MED PAOFYLLNINGSVENTIL - Google Patents

Description

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Patents and Advertising Agencies N (date of filing)

Patent · och registerstyrelaen 'AnaBkan udagd och iKUkiHtan publicarad 30.11.63 (32) (33) (31)? Y74 «* r utuoHtaua —Bagird prlorMet 2 0.11. T 8

Netherlands-Nederländerna (NL) 7Ö11U26 (71) Wavin B.V., 251 Handel, 8031 EM Zwolle, The Netherlands

Nederländerna (NL) (72) Andre Oosting, Hardenberg, Kornelis Herder, Goor,

Dirk Adriaan Vermeer, Gramsbergen, Netherlands-Nederländerna (NL) (7 * 0 Berggren Oy Ab (5 * 0 Plastic bag with filling valve - Plastsäck med päfyllningsventil

The invention relates to a plastic bag with a filling valve and a gas-permeable but fine particle filtering pocket at the same end of the bag as the filling valve, the pocket being such as to allow gas to escape from the inside of the bag into the space surrounding the bag. and that the pocket extends at least to the corner strip of the sack.

Such plastic bags with a filling valve are known. Problems may arise when these known plastic bags are stacked after filling. The powdered substance to be packed in this type of air-rich bag tends to leave the bag with the air and may adhere to the outer surface of the bag. This material then acts as a sliding device, which makes the stability of the stacked plastic bags difficult.

It has also been found that the removal of air from the stacked sacks does not occur properly. If there are slightly leaking valves or leaking parts in the bag, not only air will escape, but also some powdery substance. The latter also causes a large number of harmful sliding points in the sack stack.

65047 This slip is further increased as the powdery substance exiting the bag adheres to the outer surface of the plastic bags due to electrostatic charges.

Attempts have been made to solve these problems by roughening the outer surface of the sacks, but this roughness has not led to the desired results. Thus, powdered substances are therefore only packed in paper bags.

However, these paper bags are not resistant to moisture and can be easily damaged during long-distance transport, resulting in wasted packaged materials.

It has also been proposed to provide the entire wall of plastic bags with small pores through which only air can escape, but in practice these pores have been found to be insufficient. Not only does the air escape too slowly, but also the powdery substance escapes through the pores or the pores are filled with it.

The object of the present invention is to provide a plastic bag with a filling valve, by means of which the above-mentioned drawbacks are eliminated.

The invention thus provides a plastic bag which is mainly characterized in that the pocket is formed of a nonwoven fabric of thermoplastic fibers, most preferably polyester fibers, and that the pocket terminates a distance from the inner end of the filling valve.

The gas-permeable layer is preferably at least partially covered by at least one layer of sack material which is integral with the sack itself.

In this way, the gas-permeable layer is never in full contact with the ambient air, so that said bag handlers cannot very easily adhere to said layer. As a result, the gas-permeable layer is not easily damaged without impairing the escape of air or gas from inside the bag.

The layer of sack material which is integral with the layer of material forming the sack preferably forms the bottom layer of the sack. In this way, the filling valve can be formed at one corner of the bag, and on the other hand, the gas-permeable layer filtering the fine substance can be attached to the other corner at the same time, after which the bottom is formed. The gas permeable layer suitably extends at least from the corner strip edge inside the sack and from the end edge of the bottom part of the sack located opposite and above said corner strip.

In a very preferred embodiment, the gas-permeable layer forms a small pocket attached to the inner part of the base part and the lower corner part and preferably opposite the filling valve, whereby the pocket of gas-permeable substance extends at least to the inner edge of the corner part.

Suitably the pocket of air permeable material extends over the above-mentioned inner edge of the corner strip.

The use of an air permeable pocket is very advantageous because the bag can be easily removed from the filling nozzle of the filling machine after filling the bag, since the plastic bag, which is normally flat, can now be grasped by hand from the above-mentioned gas permeable pocket. On the other hand, this pocket is very advantageous because air can easily escape from inside the bag.

The gas permeable material is suitably a non-woven material or a thermoplastic material, in particular a non-woven material consisting of polyester or polyethylene fibers. Polyester fibers are most preferred.

The gas permeable layer allows air or other gas to escape in its own plane and perpendicular to it. In this case, the air extraction is as good as possible.

Suitably the filling valve consists of a hose attached to the bottom of the bag and having a protruding part which can be folded inwards to close the valve.

In a preferred embodiment, the filling valve comprises at least one strip of gas-permeable filter medium, 4,65047, extending from the outside into the bag.

When a gas-permeable filter media strip is used, not only the air or gas trapped in the bag during filling can escape, but also the air or gas in the bag filler, which must leave the bag later when the bag is stacked.

In a very convenient embodiment of the invention, the strip of material surrounds at least a part of the plastic valve (preferably the valve tube) and preferably extends over the end of the plastic valve inside the bag.

This allows the plastic valve to fully perform its sealing function, while fully ensuring that gas or air escapes from inside the plastic bag.

The gas-permeable strip of filter media is preferably glued or heat-sealed to the plastic valve with an adhesive strip or heat-seal, in particular located outside the bag, so that the valve remains more flexible and acts as an even better closure.

The invention will now be explained by means of a few embodiments shown in the drawings.

Figure 1 schematically shows a part of a plastic bag provided with a filling valve according to the invention.

Figure 2 schematically shows a part of a plastic bag in which, opposite the filling valve, there is a gas-permeable layer consisting of a pocket of nonwoven material.

Figure 3 is a top view of the bottom of the sack provided with the filling valve of Figures 1 and 2 and a gas permeable pocket.

Figure 4 shows a cross-section through the filling valve of Figure 3 and the gas permeable layer.

Figure 1 shows a plastic bag 1 comprising a front bag film layer and a back bag film layer, which together form a tubular film which is e.g. a polyethylene material.

65050 The bag 1 has a base 2 consisting of a first base strip 3 and a second base strip 4, which are connected to each other by an adhesive joint or a weld seam 5.

The first and second base strips 3 and 4 have an end edge 8 and 9, respectively.

When forming the base, the first and second corner strips 11 and 12 are formed at the same time. The first corner strip has a first edge 14 located inside the sack. The second corner strip 12 has a second corner end edge 13.

Once the corner strips 11 and 12 have been formed, the plastic valve tube 6 is placed on the first corner strip 11. Preferably, the inner end portion 16 is folded back toward the protruding end 17 of the valve tube 6 and secured to the first corner strip 11 and the bottom cover film layer 21.

The valve tube 6 acts as a filling valve 18 located inside the bag and extending farther into the bag than the end edge 14 of the second corner strip 12.

The free end edge 17 of the filling valve tube 6 extends beyond the inside of the bag. By means of adhesive joints or heat seals 19 and 20, the valve pipe 6 is connected to the corner strip 11 and to the bottom cover film layer 21, which is fastened along the folded back bottom strips 3 and 4. Attached to the second corner strip 12 is a pocket 22 of gas permeable material having a length that extends over the inner end edge of the second corner strip 12 into the bag.

The pocket 22 is attached in the vicinity of its free outer edge 23 to a base film 21 covering the base strips 3 and 4, which are bent opposite to each other, and immediately below the second corner strip 12 by gluing or heat sealing.

It will be appreciated that the gas permeable pocket 22 which filters the fine material will allow the gas or air used in the filling and now in the bag to escape, as the inside of the bag is now in contact with the outside through the gas permeable pocket 22. This pocket 22 65047 comprises layers 22a and 22b, the edges of which are connected to each other or are in one piece, thus forming said gas-permeable pocket 22.

When the sack is filled with a filling machine, during which the bag depends on the filling machine by means of a filling valve 6, the sack can be easily removed from the filling machine, e.g. by putting a hand in the pocket 22. The plastic bag, which is very smooth per se,

For this purpose, the mouth of the pocket is opened, after which the hand can be placed in the pocket 22 until it reaches the bottom 15 of the pocket 22. As can be seen, the bottom 15 of the pocket extends inside the bag over the edge 14 of the second corner strip 12. The second corner strip 12 and the bottom cover film 21 cannot contact each other, which ensures the best possible removal of gas or air. The bottom 15 of the pocket forms an air-permeable joint between the two layers 22a, 22b.

As can be seen, the adhesive tape portions or heat seams 24 and 25 connect the pocket bottom strips 24a, 24b to the inner surface of the inwardly bent portions and the cover film 21 and to the corner strip 12 of the layer 22b.

To fill the bag, the mouth 10 of the filling valve 6 is opened. Figure 3 shows that the adhesive tape parts or heat seals 20a and 20b are located between the inner surface of the tubular valve membrane 6 and the inwardly folded parts of the corner strips 3 and 4. In order to avoid detached parts in the cover base layer 21, the end region 27 of said layer is connected in its flat state to the valve pipe 6 over its entire width.

If desired, the cover layer 21 may be omitted, whereby the base may be formed by providing cuts in the tubular sack film and bending the base strips as described in GB Patent 1,072,856.

It should be noted that the sacks according to the invention are very advantageous because the use of a gas-permeable layer does not impair the strength of any wall of the sack. This is mainly due to the fact that said layer is covered by the bottom parts of the sack.