CZ292591B6 - Sealed paper sack and process for producing thereof - Google Patents

Abstract

The present invention relates to a sealed paper sack with a bottom closed by gluing, which has end flaps (5) folded inwards along the diagonal folds (3), and side flaps (9, 9') folded on top of the end flaps (5) along the horizontal side folds (6). The top side flap (9, 9') is attached through end glued sectors (7) and a side glue sector (8) formed on inner surface of the top side flap (9', 9) end so that, after folding, said top side flap (9', 9) remains stuck to the end flaps (5) and to the bottom side flap (9, 9'), whereby the invention is characterized in that the end flap (5) has a separation cut (10) reaching from the side fold (6) to the diagonal fold (3), and that an additional flap (11 ) thus formed on the side flap (9, 9') has been folded open before the side flap (9, 9') has been folded against the end flap (5), said end glued sectors (7) extend each on side surface of the side flap (9, 9') from outer edge (12) of the cut (10) through said additional flap (11) in the direction over inner edge (13) of the cut (10) and along the diagonal fold (3) of the end flap (5) up to the side fold (6). Described is also a process for producing such sack along with making the separation cut (10) prior commencement of folding of the end flaps (5).

Description

Sealed paper bag and method of its manufacture

Technical field

The invention relates to paper bags. In particular, the invention relates to sealing a mouth of a paper bag which is sealed by gluing. The invention can be used for both open-mouth bags and plug-in closure bags, and can be realized by conventional methods of making bags.

BACKGROUND OF THE INVENTION

In the manufacture of the paper bag, the paper web is formed into a sleeve which is cut into blanks of the required length. Then either or both ends are closed to form the bottom. If both ends are closed, a filling opening is left at the bottom between the flaps which are folded over one another.

The bottom is usually closed by first folding the flaps of the narrower ends inwards, then the flaps of the wider sides are pressed against them. Before the flaps are folded, adhesive areas are formed, namely end adhesive areas that secure the side flaps to the end flaps and side adhesive areas that secure the edge of one side flap to the other side flap.

One of the problems associated with existing paper bags is the bottom leakproofness. In particular, the bending point between the side flap and the end flap is critical. The impermeability of multilayer bags can be improved by extending the inner layers that form the closed end so that in this embodiment the edges of the layers overlap (so-called stepped bottom). However, for material reasons, it is not appropriate to overlap the two-layer bag layers only. A simple solution for multi-layer bags is the so-called partially overlapping bottom where the inner layer is longer at the end flaps and top side flaps. However, very often none of the methods described above gives satisfactory results. Furthermore, problems may arise in the production process that the machine must run relatively slowly.

The stiffness can be further increased by gluing a separate sealing part between the flaps. However, this requires the use of a separate machine unit and thus cannot be carried out in production lines already in use.

SUMMARY OF THE INVENTION

It is an object of the invention that a cut is formed at the closing end of the blank in each end flap that leads from the side fold to the diagonal fold of the end flap and to the side flap, and the additional flap thus formed lies in the plane of the side flap. With the help of the end adhesive area, the flaps are held together at the side fold.

Accordingly, the present invention provides a sealed paper bag with a bottom-sealed adhesive having end flaps folded inward along diagonal folds and side flaps folded on end flaps along horizontal side folds, wherein the upper side flap is fastened by end adhesive areas and side adhesive areas formed on the inner and outer ends of the top side flap so that the top side flap adheres to the end flaps and the bottom side flap after folding, characterized in that each end flap comprises a cut-off whose inner edge extends from the side fold to the diagonal fold, and the additional flap so formed to the side flap lies in the plane of the side flap, the end adhesive area extending always on the side surface of the side flap from the outer edge of the cut through the additional flap toward the inside cut edge along the diagonal crease, and end flap to a lateral fold.

-1 CZ 292591 B6

A preferred embodiment of the invention is that the cut extends from the end of the side fold perpendicular to the diagonal fold.

Another object of the present invention is to provide a sealed paper bag by folding the end flaps inward along diagonal folds and folding the side flaps along the horizontal side folds on the end flaps by attaching the upper side flaps to the end flaps and the lower side flaps by the end adhesive areas and the side adhesive areas on the inner surface of the upper side flap end, and the method is characterized in that first dividing cuts are formed at the end flap, and each end flap portion is Γ 10 folded inwardly along diagonal folds so that the inner edges The cuts extend from the side folds to the diagonal folds, and the additional flaps, together with the respective side K flaps, are folded into the end flaps by sequential folding according to the side folds.

The invention can be realized with a bottom machine of a conventional bag production line without additional units. 15 Also no added material is required.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are part of the detailed description of the invention.

Fig. 1 shows the closed mouth (bottom) of a bag blank with folds indicated by a dashed line.

Fig. 2 shows an orifice (bottom) with partially folded flaps.

Fig. 3 shows the mouth (bottom) with fully folded flaps.

DETAILED DESCRIPTION OF THE INVENTION

In the method of manufacturing this sealed paper bag, the end of the blank cut from the paper bag is closed by a so-called bottom machine. This machine produces diagonal folds 3 that extend from the workpiece edges 1 to the bottom 2, and a horizontal center fold 4, folds the end flaps 5 of the bottom 2 inwardly along the diagonal folds 3 and folds the side flaps 9, 9 'along 35 horizontal side folds 6 at the end the flaps 5 such that they fasten the upper side flap 9, 9 'to the end flaps 5 and the lower side flap 9, 9' by the end adhesive areas 7 and the side glue area 8 on the inner surface of the end side of the upper side flap 9 ', 9 according to the invention, they form dividing cuts 10 on the end flaps 5, and each separate part of the end flaps 5 folds inwardly by folding along the diagonal folds 3 40 so that the inner edges 13 of the cuts 10 extend from the side folds 6 to the diagonal folds 3, and the additional flaps 11 together with the respective side flaps 9, 9 fold on the end flaps 5, respectively folding according to side folds 6.

* For clarity, all the folds in FIG. 1 are indicated by a dashed line, although not all of them are formed in the first stage.

Usually, a so-called bottom part (not shown) is finally glued to the top of the bottom.

In this way, a sealed paper bag is formed which has a bottom 2 sealed by gluing having 50 end flaps 5 folded inwardly along diagonal folds 3 and side flaps 9, 9 'folded on end flaps 5 along horizontal side folds 6, wherein the upper side flap 9, 9 'is fastened by the end adhesive regions 7 and the side adhesive region 8 formed on the inner surface of the end side of the upper side flap 9', 9 so that the upper side flap 9 ', 9 adheres to the end flaps 5 and the lower side flap 9, 9 ', wherein according to

Each end flap 5 comprises a dividing cut 10 whose inner edge 13 extends from the side fold 6 to the diagonal fold 3, and to the side flap 9, 9 ', the additional flap 11 thus formed lies in the plane of the side flap 9, 9 The end adhesive region 7 extends on the lateral surface of the side flap 9, 9 from the outer edge 12 of the cut 10 over the additional flap 11 towards the inner edge 13 of the cut 10 and along the diagonal fold 3 of the end flap 5 to the side fold 6.

End glueing is not carried out on bags with a retractable closure at the closure end where the space between the folded flaps remains open and a filling opening is formed. The closure can be sealed either by making a longer end flap at the closure end or by increasing the length by gluing another flap to the top of the end flap.

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When the side flaps 9 and 9 are folded and adhered to the end flaps 5, the end adhesive region 7 is pressed against the fold so that the bottom 2 seals well even at the horizontal side fold 6 where the two outer fold surfaces meet.

Further, in multilayer bags, the adhesive is forced into the diagonal inner edge 13 of the cut 10 and seals these layers so that the wrapped material cannot penetrate between the layers of the package. The material that penetrates between the layers reduces the strength of the bag.

There are no disadvantages with the additional flaps 11 formed in the bottom, they are normally covered with the bottom panel. In fact, additional flaps 11 reinforce and reinforce the bag.

The strength of the multi-layer bag of the invention can be further increased by bonding the layers at certain locations. In particular, the end edges and the end angles of the bottom of the filled bag are critical points. In Fig. 1, adhesive areas 14 and 15 are shown which are added between the paper layers to reinforce these areas.

The invention can be used in the manufacture of monolayer and multilayer bags. The invention is preferably used in two-layer bags.

If desired, the ends of the layers of the multi-layer bag may overlap as desired, further increasing the tightness of the bag.

The sacks according to the invention can be manufactured on conventional production lines already in use. The cut 10 can be easily made in the bottom machine by conventional tools together with folds. The adhesive can be easily applied to the end adhesive regions 7 of the desired shape by conventional application rollers. The invention requires no added material and production is not significantly slowed.

Claims (2)

PATENT CLAIMS A sealed paper bag, with a bottom sealed with adhesive, having end flaps (5) 5 folded inwards along diagonal folds (3) and side flaps (9, 9 ') folded on end flaps (5) along horizontal side folds (6) wherein the upper side flap (9, 9 ') is fastened by means of the end adhesive areas (7) and the side adhesive area (8) formed on the inner surface of the end of the upper side flap (9', 9) such that the upper side flap (9) 9 ', 9) adhered to the end flaps (5) and to the bottom side flap (9, 9') after folding, characterized in that each end flap (5) comprises a cut-off (10) whose inner edge (9) 13) extends from the side folds (6) to the diagonal folds (3), and to the side flap (9, 9 ') the additional flap (11) thus formed lies in the plane of the side flap (9, 9'), 7) always extends on the lateral side surface tabs (9, 9 ') from the outer edge (12) of the cut (10) through the additional tab (11) towards the inner edge (13) of the cut (10) and along the 15 diagonal folds (3) of the end tab (5) to the lateral folds (6). Method for manufacturing a sealed paper bag according to claim 1, wherein the end flaps (5) are folded inward along the diagonal folds (3) and the side flaps (9, 9 ') are folded along the horizontal side folds (6) on the end flaps (5). such that the upper side flap 20 (9, 9 ') is fastened to the end flaps (5) and the lower side flap (9,9') by means of the end adhesive regions (7) and the side adhesive region (8) on the inner surface of the end upper side flaps (9 ', 9), characterized in that dividing cuts (10) are formed on the end flaps (5), and the portions of the end flaps (5) are each folded inwardly by folding along the diagonal folds (3) such that the inner edges (13) of the cuts (10) extend from the side folds (6) to the diagonal folds (3), 25, and the additional flaps (11) together with the respective side flaps (9, 9 ') are folded onto the end flaps (5), gradual transfer according to p creases (6).