WO1989012582A1

WO1989012582A1 - Self-adhesive sealing flap

Info

Publication number: WO1989012582A1
Application number: PCT/SE1989/000327
Authority: WO
Inventors: Jan Söderholm; Hugo Cedraeus
Original assignee: Soederholm Jan; Hugo Cedraeus
Priority date: 1988-06-13
Filing date: 1989-06-09
Publication date: 1989-12-28
Also published as: SE8802209D0; SE461329B; SE8802209L

Abstract

The object of the invention is to provide a self-adhesive sealing flap (4) with a cover film (6), which can be mass-produced in a simple, rapid and inexpensive manner and is easily usable also by an unexperienced person. According to the invention, this is achieved in that the flap (4) has at least one pull tab (8), that an opening slit (9) is formed in the flap (4) and the cover film (6), that around the opening slit (9) there is applied a cover portion (11) in the cover film (6), that the opening slit (9) is covered with a releasable strip (12), and that along one longitudinal side (13a) of the flap there is made a through punch (14) in the cover film (6).

Description

SELF-ADHESIVE SEALING FLAP

The invention relates to a self-adhesive sealing ^"flap comprising the flap proper, a self-adhesive layer of adhesive on one side of the entire flap, and a cover film on top of said adhesive layer. The object of the invention is to provide a self- adhesive sealing flap of this type, which is intended to seal covers, envelopes, wrappers, sample bags and other packings and the like which are sealable with a flap. It should be possible to mass-produce the sealing flap in a simple and rapid manner and at low cost, and to readily reopen the cover or the like which has once been sealed with a self-adhesive sealing flap according to the invention. Moreover, this self- adhesive sealing flap should be easily usable, and the sealing as well as opening thereof should be easily comprehensible also to an unexperienced person. The flap should further be easily variable in size and adaptable to different formats.

According to the present invention, this is achieved by a combination of the characteristic features that a) one of the flap corners is cut off, and the cover film on/under this flap corner forms a pull tab, b) an opening slit is formed in both the flap and the cover film, c) around the opening slit, there is applied a punched cover portion in the cover film only, d) on the side of the flap facing away from the cover film, a releasable strip is applied over the opening slit, and e) parallel with the flap side facing away from the cut-off flap corner, a through punch is made in the cover film so as to form a separately releasable protective strip. The releasing of the cover film as the sealing flap is used, is rendered easy to both right-handed and left- handed persons, if both flap corners on one and the same flap side are cut off, while the cover film on/under the flap in these two corners forms two pull tabs.

It is in some cases important that unauthorised persons should not be able to open packings without the occurrence of the opening being visually evident. To this end, the self-adhesive sealing flap according to the invention can be modified to the effect that the releasable strip which is applied over the opening slit on the side of the flap facing away from the cover film, is of such, per se known, design that the strip is releasable only once and subsequently is no longer adhesive.

Further embodiments of the invention are stated in the subclaims.

The invention will now be described in more detail with reference to the accompanying drawing which illustrates an embodiment of the invention. In the drawing, Fig. 1 is a top plan view of a bag having one compartment and one sealing flap, whereas Fig. 2 is a cross-sectional view of a packing with two com¬ partments and a double flap in a not yet sealed position, the thickness of the different layers being magnified for better clarity.

In the example illustrated in Fig. 1, a sample bag 1 having one compartment 2 which has been formed by edge sealing 3 of two superimposed layers (not shown n detail in Fig. 1 ) , is provided with a self-adhesive sealing flap 4 according to the invention.

This sealing flap is composed of the flap 4 proper which has two longitudinal sides 13a and 13b extending in parallel with one another. On the longitudinal side 13b, both flap corners 7 are cut off. On top of said flap 4, a cover film 6 is applied, which at the cut-off flap corners 7 forms two pull tabs 8. Of course, the sealing flap can also be designed with only one cut-off flap corner 7 and only one pull tab 8. The colour of the cover film conveniently differs from that of said flap. In the cover film 6 and the actual flap 4 , a through opening slit 9 is punched. Around this opening slit 9, a cover portion 11 is punched in the cover film only. This cover portion adheres around the opening slit, since in fact the entire flap 4 is covered with a self-adhesive layer of adhesive. If one releases the cover film 6 by pulling one of the pull tabs 8, the cover portion 11 thus remains on the actual flap 4. As will be described in detail below, this is especially important. Moreover, a through punch 14 merely in the cover film is made in parallel with and at a certain distance from the longitudinal side 13a of the flap facing away from the cut-off flap corners 7. Thus, the cover flap can be manufactured in flow production as a long windable web, be divided transversely of the longi¬ tudinal direction in some suitable manner, for example by means of perforations, cutting or the like and be connected with the sample bag 1 , after the narrow protective strip 10 formed by means of said punch 14 has been released, whereby an adhesive strip 18 is exposed.

After said sealing flap has thus been adhered, by means of the adhesive strip 18, to the upper part of the sample bag 1, there is formed a double-walled layer consisting of the flap strip 18 and the upper edge of the sample bag 1 , whereby as the flap is folded down a fold line arises, as indicated by the dash-dot line in Fig. 1 and designated 15, along which the flap is folded .so that the opening slit 9 will be positioned at the level of the opening edge 2a of the compartment 2. According to the invention, there is applied a releasable strip 12 over the opening slit 9 on the side of the flap 4 facing away from the cover strip 6. One or each end of this strip is suitably provided with a grip tab 19. To form the grip tab 1 in per se known manner, the strip has no adhesive layer ^"precisely on the tab, or the grip tab is, for example, folded back on itself. This strip has in Fig. 1 been indicated by dashed lines, since it is positioned on the side of the flap 4 facing away from the viewer. The cover portion 11 which is disposed on the side of the flap 4 facing the viewer and which like toe flap 4 also has a through opening slit 9 functions as follows. When the cover film around the cover portion 11 has been released and the flap has been folded down and pressed against the sample bag which, as a result, is sealed, the flap does not, owing to the remaining cover portion 11 , adhere around the opening of the compartment 2. It would per se have been possible to obtain this effect also by letting a portion corre¬ sponding to the cover portion 11 remain free from the self-adhesive layer of adhesive. However, this complicates the manufacture and renders it more expensive, since for each flap size, there must be provided a different roller for applying the adhesive. Besides, the application of the cover strip to the flap and the positioning of the portion which is not coated with any self-adhesive layer of adhesive must be co¬ ordinated, which complicates the manufacture and makes it more expensive and also causes rejections. Owing to the invention, one and the same adhesive application roller can be used for practically all flap sizes, both in respect of flap length and flap width, and this has appeared to be an unexpected advantage.

When the sealed sample bag is to be opened by releasing the strip 12, it would be more difficult to obtain access to the compartment 2 if the flap had adhered adjacent to the opening slit 9. However, this is not the case because the cover portion facilitates access to the compartment 2 in the bag. Further the cover portion 11 brings the unexpected advantage that the flap need not be folded exactly over the sample bag and the opening of the compartment 2, since the slit ^*"9 can simply be positioned slightly above or below the opening 2a of the compartment, as seen in Fig. 1. If also the cover portion had been released, it might have been more difficult to open the compartment 2, since the slit 9 does not conform exactly to the opening 2a of the compartment, and, as a result, the compartment as well as the opening 2a thereof would have been sealed.

It is in some cases desired to make it impossible to open sample bags without leaving any visual traces, in order to make certain that no one has previously opened the compartment and possibly tampered with its contents. To this end, the invention suggests that the releasable strip 12 be of such type that it can be released only once and subsequently no longer adheres. Such strips are known, and therefore their mode of functioning need not be explained in detail.

Fig. 2 shows a modification of the present invention, where the self-adhesive sealing flap is designed as a double flap and is used together with a sample bag having two compartments, one compartment being intended for the sample proper, whereas the second compartment is intended for a delivery note or the like. Both compartments should be openable independently of each other. As appears from Fig. 2, the self-adhesive sealing flap according to the invention is doubled and thus provided with two releasable strips 12 each of which covers its opening slit 9. The opening slit 9 extends through the flap 4, the adhesive layer 16 and the cover film 6. Also in this case, the slit is surrounded by a cover portion 11. Between the right-hand and left-hand cover strip 6 in the Figure, a protective strip is released which then exposes a self-adhesive section 18 by means of which the sealing flap is attached to the sample bag 1. The sealing and opening of the two compartments of the sample bag occur in the manner "described above. The walls of the compartment are here understood to be of a shock-absorbing material.

Claims

1. A self-adhesive sealing flap comprising the flap (4) proper, a self-adhesive layer of adhesive on one side of the entire flap, and a cover film (6) on top of said adhesive layer, c h a r a c t e r i s e d in that a) one of the flap corners (7) is cut off, and that said cover film on/under this flap corner (7) forms a pull tab (8), b) an opening slit (9) is formed in both said flap (4) and said cover film (6), c) around said opening slit (9) there is applied a punched cover portion (11) in said cover film (6), d) on the side of said flap (4) facing away from said cover film (6), a releasable strip (12) is applied over said opening slit (9), and e) parallel with the flap side (13a) facing away from said cut-off flap corner (7), a through punch (14) is made in said cover film (6) so as to form a separately releasable protective strip (10).

2. The self-adhesive sealing flap according to claim 1, c h a r a c t e r i s e d in that two of said flap corners (7) on one and the same flap side (13b) are cut off, and that said cover film on/under these flap corners (7) forms two pull tabs (8).

3. The self-adhesive sealing flap according to claim 1 or 2, c h a r a c t e r i s e d in that said opening strip (12) is releasable only once and subsequently no longer adheres to its substrate.

4. The self-adhesive sealing flap according to claim 1, 2 or 3, c h a r a c t e r i s e d in that the colour of said flap (4) differs from that of said cover film ( 6 ) .

5. The self-adhesive sealing flap according to one or more of the preceding claims, c h a r a c t e r - i s e d in that it is doubled, the doubled flaps (4) being produced in one piece, whereas the cover film (6) is divided into two parts separated by a separately releasable protective strip (10) which ^*- is disposed therebetween and made of the same material as the cover film.

6. The self-adhesive sealing flap according to one or more of the preceding claims, c h a r a c ¬ t e r i s e d in that said opening strip (12) is heat-sealed to the opening slit (9) of said flap (14), while leaving a grip tab (19) in one or each end of said opening strip (12).