CZ9904589A3 - Close sack with air exhaustion - Google Patents

Abstract

The invention relates to a close sack with a tubular mantle with an air-permeable inner layer (1) of paper, outside of which a separate air-impermeable barrier layer (2) and outside of that an outer layer (3) of paper. Both ends of the mantle have a plane bottom, one of which has a filling valve (12) on its end. During the filling of the sack, air flows from the sack to the area between the inner layer (1) and the barrier layer (2) and is allowed to escape from between the layers in the bottom to the area between the side flaps (5.1, 5.2) and out from there through the ends of the bottom. The sack can have a completely intact barrier film yet air exhaustion is efficient. The bottom glueing is nevertheless as tight as possible.

Description

BACKGROUND OF THE INVENTION The present invention relates to paper bags and may be applied to valve bags with a protective layer, and further relates to their manufacture and use. In particular, the bags according to the invention can be used for storing products which must be packed as tightly as possible.

BACKGROUND OF THE INVENTION

In the manufacture of paper valve bags, the paper strips are formed into a tube, cut into pieces of desired length, the ends closed to form the bottom by first folding the thinner end flaps inwards, and the wider side flaps fold over their upper side. At all ends, except the valve end, the side flaps are attached to the end flaps. A separate valve piece made of paper may be added to the valve end. Further, the valve may comprise a closing flap that folds after attachment of the bag and attaches to the bottom of the bag via the valve mouth.

The moisture-resistant valve bags were made of paper coated with plastic film or by inserting loose plastic film between the paper layers. The plastic is preferably polyethylene.

Valve bag problems arise when filling bags, where air must be allowed to escape from the bag. This is especially a problem with transparencies. Therefore, the protective perforated, which is substantially foil.

A multi-layer bag for air during filling, bags equipped with a protective layer of these bags usually deteriorates the protective properties to be formed as permeable as also mentioned in 9 9 9 · ·· ·

FI-A-945831. Then the inner layer is made of paper with good breathability and has channels on its outer surface. During filling of the bag, the air trapped between the layers moves through the channels to the ends of the bag where it can escape. The ends of the mouth of the bag blank are in the bag with each other. However, this construction is not sufficiently tight for all applications. Further, in practice this bag needs a separate bottom cover layer.

Of the invention

These drawbacks are overcome by a tight bag with a tubular sheath with a breathable but dust-filtering inner paper layer, the outer side of which is a separate breathable protective layer and one or more outer paper layers outside, with a flat bottom at both ends of the housing with the side flaps are folded over the top side of the end flaps of the invention, which consists in that in the side flap at the bottom in the bottom, the inner layer is longer than the protective layer and the outer layer is shorter than the protective layer and in the side flap at the top and the outer layer is longer than the protective layer. The inner surface of the inner side flap layer at the top is glued to the outer surface of the inner side flap layer at the bottom by the inner side adhesive tape. The inner surface of the outer flap layer is adhered at the top to the outer flap surface of the bottom flap with an outer adhesive tape, thereby allowing air to escape from the area between the inner flap and the protective layer at the bottom between the side flap and outward end of the bottom.

In the bag according to the invention, a completely air and moisture impermeable protective layer can be used, while still removing the air during the filling of the bag. Also, the bottom of the bag is very tight due to the overlapped construction.

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An exemplary embodiment of a bag according to the invention is shown in the accompanying drawings, in which Fig. 1 is a bag blank prior to forming the bottom; FIG. 2 is a blank to which a valve member has been added; FIG. 3 is a blank with end flaps folded; Fig. 4 is a blank on which adhesive tapes have been formed; FIG. 5 is a blank in which the side flaps to be underneath are folded; and Fig. 6 is a finished bag.

DETAILED DESCRIPTION OF THE INVENTION

The bag according to the figures is made of a three-layer material. Most inside is the inner layer 1 of paper, outside of which there is an airtight protective layer 2, and most outside is the layer 2 of paper. At both ends of the flattened tubular blank (FIG. 1), notches 4 are formed from the ends to form the side flaps 2 and end flaps. In the region of the side flaps 2, the blank is slightly longer than in the region of the end flaps 2. side grooves .2. bottoms along which the blank is folded to form a planar bottom, as well as folding grooves 2 along which the bottom is folded over the shell.

The inner layer 1 and the outer layer 2 may be of bag paper suitable for this purpose (strength e.g. 95 g / m ² ). The protective layer 2 may be of a suitable plastic film (eg HDPE).

The protective layer 2 is attached to both ends of the inner layer 2 by transverse spot gluing 10 and to the outer layer 2 by transverse gluing 11, which in this case is also spot gluing. Gluing helps to align the layers as well as to reinforce the bag, since stress is distributed more evenly across all layers.

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In the region of the side flaps 2, the ends of the layers are graduated to be of different lengths so that the upper end of the blank on the front side of the inner layer 1 is longer and the outer layer 2 is shorter and the inner side 1 is shorter and outer layer 2 longer. At the lower end of the blank on the front side of the housing, the inner layer 1 is shorter and the outer layer 2 is longer, and on the back side the inner layer 2 is longer and the outer layer 2 is shorter. Grading the length of the material allows all materials to be attached to each other when building the bottom.

In the region of the end flaps 6 at the upper end, the inner layer 1 is slightly longer than the protective layer 2 and the outer layer 2. At the lower end, the inner layer 1 is somewhat shorter than the protective layer 2 and the outer layer 2.

In another operation (FIG. 2), the paper valve portion 12 is attached to one end of the upper end of the blank. Its lower end is placed in the region of the side groove 7 and its upper end reaches slightly above the side flaps 2. The valve member 12 is glued to the end flap 6 slightly from both sides slightly out of the slot 4 in the longitudinal adhesive tape.

13. On the inside of the lower end of the valve member 12 is a fold. Its upper edge is at the level of the upper edge of the outer layer 2 of the end flap 6. A further line 22 is indicated on the valve member 12 along which the valve member is folded together with the side flap 2 along the side groove 11.

In a further operation, the side flap 2 of the front side is folded open along the folding groove 2 while folding the end flaps 4 inwardly along the end grooves 4. Further, the sides of the valve member 12 are folded inwardly in the region of the side grooves 7, and the adhesive tapes 15 are applied to the top of the folded sides from the edge of the inward fold. In the region of the double edges of the valve member 12, the adhesive tape is slightly wider. Then ·· ··

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4, the side edges of the vendil piece 12 are folded open again and adhered tightly to the end flap 4 to the inner layer of the side flaps 2.

In the next operation (Fig. 4), adhesive tapes are applied to close the lower parts. On the side of the flaps 51 to be underneath where the inner layer 1 is the longest, end adhesive tapes are applied from the outside of the end flaps 6 from the side grooves 7 to the inner surface of the side flap until they reach the end. On the side flap 5.2. similar to, but shorter adhesive strips 16.2 are applied to the top where the inner layer 1 is the shortest. Further, the end adhesive strips 16.2 are joined along the edge of the inner layer 1 to the inner thinner side adhesive tape 17. At the end of the outer layer 1, a thin outer side adhesive tape 18 extending from one end to the other end is applied to the inner side. In the region of the valve piece 12, the end bands 16.1 and 16.2 and the inner side adhesive tapes 17 are naturally applied to the top of the valve piece 12.

In the next operation (Fig. 5), the side flaps 5.1. which are to be underneath, fold over the bottom, as a result of which the inner surface of their inner layer 1, by means of end adhesive strips 16.1. Tightly adheres to the end flaps 6 and at the valve end, correspondingly to the valve member 12. When the side flaps 5.2 to be top are finally folded over the bottom, its outer layer 2 adheres to the outer layer of the lower side flap 5.1 by means of an outer the side adhesive tape 18 and the inner layer are adhered to the end flap 8, in the valve corner to the valve member 12, and to the inner layer of the lower side flap by means of the end adhesive strips 16.2 and the inner side of the adhesive tape 17.

Thus, in the bottom construction, all paper layers 1 and 2 are glued in the longitudinal direction of the bag to each other by adhesive tapes 12 and 18. Stepped protective layer 2

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Aft ft • ft is not glued longitudinally together, but is glued transversely by spot gluing to paper layers. Therefore, the loose non-glued construction allows air to be vented from the ends of the bottom, but because it overlaps, it provides moisture protection in the bottom construction. The protective layer can be glued in a cheap manner of gluing; no expensive and special adhesives are required.

Adhering the corners of the bottom of the seams 16.1 and 16.2 closes and seals the structure, but allows the dust-free air coming between layers 1 and 2 to escape from the ends of the bottom.

The bottom structure is completely sealed towards the inside of the bag except for the valve having a filling opening between the outer layer of the end flap 6 and the valve member. When the bag is filled, the material inside presses the end flap 6 tightly against the valve member 12. If necessary, the valve mouth may also be further closed separately with a sealing tape attached through the mouth to the bottom. Due to the overlapping construction of the materials, the bottom is completely covered with an intact protective foil 2.

During filling of the bag, air moves from the bag to the area between the inner layer 1 and the protective layer 2 and from there flows out their end in the bottom of the bag. At the bottom, the air moves between the side flaps 5.1 and 5.2 to the ends where it can escape (Fig. 5). In order to facilitate air travel, the outer surface of the inner layer 1 may be grooved, but paper with a smooth surface is also suitable.

Air extraction is very effective when air flows on both sides of the bag to both ends of the bag.

No cover layer is needed to create an air channel or to increase the strength of the bag.

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The sacks can be manufactured on a tube making machine and a bottom of conventional sack production lines with other jigs allowing the necessary cuts, overlaps and gluing. No special material is needed.

The bag is particularly suitable for use for materials that need to have the best possible protection against external air humidity (eg cocoa) or for materials whose leakage from the bag must be prevented as much as possible (eg environmentally hazardous chemicals).

Claims (2)

PATENT CLAIMS n · «· < • · · · «« 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 4 4 4 1 Tight bag with tubular sheath, with an air permeable but dust-filtering inner layer (1) of paper, outside which a separate air-impermeable protective layer (2) and one or more outer layers (3) of paper are outside this layer , at both ends planar inwardly through the upper skins, the folded folded bottom with the end flaps (6) and the side flaps (5,1, 5.2) is the side of the end flaps (6) characterized in that in the side flap (5.1) underneath the bottom, the layer (1) is longer than the protective layer and the outer layer (2) is shorter than the protective layer (2), and in the side flap (5.2) above, the inner layer (1) is shorter (3) is longer than the inner surface is glued over the protective layer (2) and the outer layer a protective layer (2), the inner layers (1) of the side flap (5.2) on top the outer surface of the inner layer (1) of the side flap (5.1) from below the inner side of the adhesive tape (17); The outer surface (3) of the side flap (5.2) at the top is adhered to the outer surface of the side flap (5.1) from below by the outer side of the adhesive tape to escape air from the area between the protective layer (2) in the bottom into (18). (1) and the areas between the side flaps (5.1, 5.2) and thence out the bottom of the bottom. Bag according to claim 1, characterized in that air can escape at both ends of the bottom. 3. Bag according to claim 1 or 2, h marked by that air can leak both ends bags. 4. Bag according to claim 3, s n by doing so the air can move in the region between the inner layer (1) and the protective layer (2) on both sides of the bag to both ends of the bag. 9 ·· * · · · • · · • »3 · • »· · • 4 ♦ » · 1 · · • · • · · • · · ··· • • • · • »« ·· • · · · 9 9 9 · • ♦ · • 9 9 99 · « 5. Bag according to any of claims 1 to 4, marked t i m that protective layer (2) Yippee stuck to the inside layer (1) or external layer O; ) on the lateral end of the mantle spot gluing (10/11) 6. Bag according to any of claims 1 to 5, that on the bottom there is no protective marked by the bottom layer.