FI111617B - A closure bag and a method of making a closure bag - Google Patents

Description

111617

TECHNICAL FIELD OF THE INVENTION A SACK AND A METHOD FOR MANUFACTURING A SACK

The invention relates to paper bags and relates to a multilayer bag having a barrier film between the paper layers 5.

TECHNICAL BACKGROUND

In the manufacture of paper multilayer valve bags, a stack of paper webs superimposed is formed, the desired lengths of the hose are cut and their mouths closed. Moisture-proof valve bags can be made by placing a loose plastic film between the paper layers. In particular, polyethylene has been used as the plastic.

The strength of the multilayer bag can be increased by gluing the layers together. In particular, reinforcing bonding is performed with a transverse adhesive seam 15 in the mouth of the bag. Gluing also facilitates the alignment of the sack layers during the manufacturing process. When the sack has a plastic film between the paper layers, it is difficult to glue together materials of very different properties. In the gluing, soft dispersion adhesives have to be used, which in themselves are difficult to handle. In addition, they require a long drying time of up to one week. However, the end result may still be uncertain and not even easy. check because the adhesive seam is invisible.

• · ·

For example, FI-A-972664 discloses a sack having a plastic film between paper layers.

GENERAL DESCRIPTION OF THE INVENTION

A bag according to claim 1 and a method for its manufacture have now been discovered. Preferred embodiments of the invention are set forth in the dependent claims.

In the bag according to the invention, a barrier film completely impermeable to air and moisture can be used between the paper layers. The paper layers are glued to each other, making it easy to align the layers in the manufacturing process. At the same time, the strength of the bag 30 increases. For gluing, conventional adhesives suitable for paper gluing can be used.

2 111617

DRAWINGS

The accompanying drawings are a part of the detailed description of the invention. In the drawings, Fig. 1 shows a sack blank before forming the bottoms, Fig. 2 shows a blank with a valve piece inserted, Fig. 3 shows a blank with bottom sizing, Fig. 4 shows a blank with lower side tabs folded, and Fig. 5 shows a finished sack.

10 DETAILED DESCRIPTION OF AN EMBODIMENT

The bag shown in the figures is made of a three-layer material. The inside has a paper inner layer 1, an outer air-impermeable barrier layer 2 and an outer paper outer layer 3. The flattened tubular blank (Fig. 1) is provided at each end with cutouts 4 to obtain side strips 5 and end strips 15. longer than the end strips 6. The figures also show the transverse side openings 7 and the diagonal end openings 8 along which the flat base is formed by folding, and the folding openings 9 along which the bottom is folded against the diaper.

The inner layer 1 and outer layer 3 may be suitable sack paper (thickness 20 e.g. 95 g / m 2). The barrier layer 2 may be a suitable plastic film (e.g. HDPE).

At the side strips 5, the ends of the layers are staggered to varying lengths such that at the top of the blank, the front side of the sheath has an inner layer 1 longest and an outer layer 3 shortest and a back side has an inner layer shortest and outer layer longest. At the lower end of the blank, the front side of the diaper has an inner layer 1 the shortest and the outer layer 3 the longest, and the back side has an inner layer the longest and the outer layer 25 the shortest. The staggering of the material allows each material to be joined together in the base structure.

At the end strips 6, at the upper end, the inner layer 1 is slightly longer than the barrier film 2 and the outer layer 3. At the lower end, the inner layer 1 is slightly shorter than the barrier layer 2 and the outer layer 3.

Layers 1, 2 and 3 are secured at each end by transverse dot gluing 10. The gluing helps to align the layers. In addition, they reinforce the sack as strain is applied more evenly to all layers.

111617 3

The adhesives are formed such that a row of holes 11 is formed in the barrier layer 2 before the layers are overlapped and the paper layers are glued together through these holes. Thus, the gluing itself can be carried out using conventional methods and materials used in the manufacture of the sack, using for example starch glue. 5 star jelly is cheap, easy to use and quick-drying. The end result is very reliable.

The holes 11 can be formed in the barrier film by cutting, for example, with a suitable Stans die tool. By heating a meltable film, such as a plastic film, the holes can be made by melting with a suitable hot pin.

In the next step (Fig. 2), a paper valve body 13 is attached to one end of the upper end of the blank. The valve body 13 is glued to the end strip 6 with two adhesive strips. The valve body 13 has a fold 14 on the inside. The front side flaps 5 are folded open along the fold flap 9, while the end flaps 6 are folded inwardly along the end flaps 8. In addition, . In the region of the double end edge of the valve body 13, the adhesive strip 15 is slightly wider. The side edges of the valve body 13 are then flipped open and adhered tightly to the end strip 6 on the inner layer of the side strips 5.

In the next step (Fig. 3), adhesive strips are formed by means of which the bottoms are closed. The downstream side strip 5.1, where the inner layer 1 is the longest, is formed with end adhesive strips 16.1 extending from the outer surface of the main strip 6 to the inner surface of the side strip from the side strip 7. On the incoming side strip 5.2, where the inner layer 1 is the shortest, similar shorter end adhesive strips 16.2 are formed. Further, the end adhesive strips 16.2 are joined along the edge of the inner layer 1 with a narrower inner side adhesive strip 17. At the end of the outer layer 3, a narrow end-to-end outer adhesive strip 18 is formed on the inner side.

In the next step (Fig. 4), the side strips 5.1 coming down from the bottom are folded, whereby the inner surface of the inner layer 1 tightly adheres to the end strips 6 and the 5.1 to the outer layer by the outer side adhesive strip 18 and the inner layer 1 to the end strip 6, at the valve angle to the valve body 13 and 4 111617 to the inner side layer of the lower side strip by the end adhesive strips 16.2 and the inner side adhesive strip 17.

Thus, in the base structure, each paper layer 1 and 3 is glued longitudinally against the sack (staggering) by means of seam seams 17 and 18. The staggered barrier layer 2 is non-self-adhesive in the longitudinal direction but secured to the paper layers by glue 10. In this way, the free non-adhesive well structure allows air to escape from the ends of the base, but interleaved forms a moisture barrier to the base structure. The barrier layer can be glued with cheap process sizing; expensive and stain-resistant special adhesives are not needed.

10 Gluing the corners of the soles with seams 16.1 and 16.2 seals and seals the structure, but allows dust-free air to escape between the layers 1 and 2 at the ends of the sole.

The bottom structure is completely sealed inwardly of the sack except for the valve having a filling opening between the outer layer of the end strip 6 and the valve body. The material inside the filled sack 15 presses the end strip 6 tightly against the valve body 13. If desired, the valve mouth may be further closed individually with a closure tab fastened over the bottom. Due to the overlapping of materials, the bottom has an intact barrier film 2 at each point.

As the sack is filled, air passes from the sack between the inner layer 1 and the barrier layer 2, from where it comes out of their ends at the bottom of the sack. In the soles, air passes between the side strips 5.1 and 5.2 to the ends where it exits. In order to facilitate air passage, the outer surface of the inner layer 1 may be grooved, but even a smooth surface paper will work.

Deaeration is very effective when air passes through each side of the sack at each end of the sack.

A base plate is not required to form the exhaust air duct or to increase the strength of the bag.

The sacks can be made on hose and bottom machines of a conventional bag making line with inserts to make the necessary cuts, overlaps and gluing. No additional material is required.

Claims (11)

A latching bag with a hose-shaped jacket comprising an inner layer (1) of paper, outside of which is a separate air-impermeable liner (2) and outside of it an outer layer (3) of paper, the men having an even bottom at each end, characterized in that the barrier layer (2) has shark (11), to which the inner layer (1) and the outer layer (3) are glued together. i 15 Sack according to claim 1, characterized in that there is shark (11) within the area of the bottom. Sack according to claim 1 or 2, characterized in that there are shark (11) in a row. Sack according to claim 3, characterized in that there is shark (11) in the transverse row of the jacket. 20 Sack according to any of claims 1-4, characterized in that the bottom has non-folded end flaps (6) and on these folded side flaps (5.1, 5.2), in the side flap (5.1) which lies at the bottom of the bottom is the inner layer (1) longer than the barrier layer (2) and the outer layer (3) shorter than the barrier layer (2) and in the upper side tab (5.2), the inner layer (1) is shorter than the barrier layer (2) and the outer layer (3) ) longer than the barrier layer (2), the inner surface of the inner layer (1) of the upper side flap (5.2) has been glued to the outer surface of the inner layer (1) of the underlying side flap (5.1) with an inner side adhesive strip ( 17), the inner surface of the outer layer (3) of the upper side flap (5.2) has been glued to the outer surface of the underlying side flap (5.1) with an outer side adhesive strip (18), air being able to pass out between the inner layer (1) and the barrier layer (2) in the bottom between the side flaps (5.1, 5.2) and out from the end of the bottom. 111617 6. A bag according to claim 5, characterized in that air can pass from each end of the bottom. Sack according to claim 5 or 6, characterized in that air can pass out from either end of the bag. 5 Bag according to claim 7, characterized in that air can pass between the inner layer (1) and the barrier layer (2) on each side of the bag to each end of the bag. Bag according to any of claims 1-8, characterized in that no end flap is in the bottom. A method of making a latch bag, with a tubular jacket including an inner layer (1) of paper, outside of which is a separate air-impermeable latch (2) and beyond it an outer layer (3) of paper, wherein the mint has even bottom at each end, characterized in that shark (2) is formed in the barrier layer (2), and the inner layer (1) and the outer layer (3) are glued together at these shark. 11. A method according to claim 10, characterized in that the barrier layer (2) is heat-sealable film and the heel (II) is made by the fusible melting pin. , 1