GB2023539A - Bags - Google Patents

Abstract

An open-mouthed bag formed from superimposed plies of thin flexible sheet material is provided with a region of adhesive (14, 15) on an outer surface of the bag. Closure of the bag can be effected by folding the bag to bond the adhesive region (14, 15) with a further region (13) of the outer surface of the bag, which further region may also be an adhesive region. The adhesive can be conveniently applied by an ink- printing technique. <IMAGE>

Description

SPECIFICATION Bags This invention relates to bags formed from superimposed plies of thin flexible sheet material and having open mouths defined between adjacent peripheral portions of the plies.

It is known to provide said bags with means for holding closed the mouths thereof, such means including mechanical closure devices particularly in the case of plastics carrier bags, and adhesive strips on the inner surfaces of flaps particularly in the case of envelope type bags. With such known means however considerable manufacturing cost and complexity may be involved whereby said means may not be suited to use in the context of inexpensive mass-produced bags.

An object of the present invention is to provide a closure means for a bag which can be applied to the bag in a simple and inexpensive manner.

According to one aspect of the invention therefore there is provided a bag formed from superimposed plies of thin flexible sheet material and having an open mouth defined between adjacent peripheral portions of the plies, said bag having adhesive applied to at least one region of the outer surface of at least one of said plies thereof whereby said bag can be folded so as to close said open mouth and bring the or each said adhesive region into engagement with at least one further region of the outer surface of at least one of said plies such as to form a bond therewith and thereby hold said open mouth closed.

With this arrangement, in so far as the adhesive is applied to an outer surface of the bag, it is possible for the application of the adhesive to be effected in a particularly simple and inexpensive manner. In particular the adhesive may be applied by a printing technique, especially a relief or intaglio printing technique, and it will therefore be appreciated that application of adhesives can be effected extremely conveniently in so far as the technique of application and the apparatus used therefor need be no different from the technique and apparatus conventionally used in the application of decorative or informative printing to the bag.Thus, and in accordance with a second aspect of the present invention, there is provided a method of forming a bag as described above wherein the application of the adhesive is effected by a printing technique using a printing roller which is fed with said adhesive in liquid or fluent form. With this method, by incorporation of appropriate inks in the adhesive, the or each adhesive region can also function as a region of informative and/or decorative matter.

Most preferably, the adhesive is of a pressure sensitive kind and said adhesive is also applied to the or each said further region. Thus, and in accordance with a particularly preferred embodiment the or one first said region is an elongate region extending longitudinally of and adjacent to one said peripheral portion, and the or one said further region is an elongate region extending longitudinally of and adjacent to said other peripheral portion, said two elongate regions being spaced from each other transversely such that at least one of said plies can be folded over at the said mouth to bring said elongate regions into contact with each other.

One said elongate region may be provided on a projecting flat integral with one ply.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Fig. 1 shows a moving web of paper used in the manufacture of one form of a bag according to the invention; Fig. 2 shows a finished bag; Fig. 3 shows the mouth of the bag to a larger scale in a closed condition; and Fig. 4 illustrates the application of adhesive to the paper web during manufacture of the bags.

As shown in Fig. 1, paper bags of the kind used for packaging merchandise are mass produced from a moving web of paper 1.

The paper 1 is cut transversely at intervals to define paper strips 2 each having a cut-out portion 3 at the leading side 4 and a projecting flap 5 at the trailing side 6.

Each strip 2 is folded along the dotted lines 7 shown in Fig. 1 so that the edge regions 8 overlap and a flat tubular structure having superimposed plies of paper is defined; and the flap 5 is folded up to define a closed-bottom bag. The overlapping edge regions 8 and flap 5 are giued in position.

As can be seen from Fig. 2, the finished bag has an open mouth defined between the edge portions 9 and 10 and 11 of the leading side 4 of the strip, the portions 10, 11 projecting beyond the portion 9 to define a flap 12.

The arrangement so far described is wholly conventional.

Contrary to conventional practice, however, adhesive stripes 13, 14, 1 5 are applied to the paper web 1 on one surface thereof before the strips 2 are cut from the web.

As shown in Fig. 4, an intaglio or relief printing technique is used to apply the adhesive, the web 1 being passed between rollers 16, 17, one roller 16 having elongated printing portions 1 8 in relief or recessed as appropriate, and an inking mechanism 19 being provided for feeding an adhesive in liquid or fluent form to the printing roller 1 6. The adhesive may be in solution, in the form of an emulsion or in the form of a hot-melt as desired.

As shown in Fig. 1, the stripes 13, 14, 1 5 are applied such as to extend alongside the edge portions 9, 10, 11 of the leading side 4 of the strip 2 and such stripes in the finished bag (Fig. 2) define two stripes on the outer surfaces of the opposite plies of the bag adjacent the edges defining the open mouth of the bag.

The stripes in the finished bag are freely exposed and are spaced, due to the presence of the projecting flap 12, in a direction transversely of the edges of the mouth, whereby as shown in Fig. 3 the flap 12 can be folded over to close the mouth of the bag and bring the adhesive stripes on the two outer surfaces into contact with each other. The adhesive used is such that it quickly dries after initial application to the paper web 1 so as to become dry and non-tacky to the touch, but a bond is readily formed when the adhesive stripes are pressed into contact with each other.

The bond may be of a permanent-nature or such that the adhesive stripes can be separated and rebonded together as and when desired.

With the arrangement so far described, stripes of a very small amount of adhesive can be applied to the paper web using a technique and apparatus such as are conventionally used for printing decorative and/or informative matter on the web whereby the added cost and complexity involved in providing the bags with the stripes may be very small.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Thus, for example, the invention is not restricted in application to paper packaging bags.

Other materia!s, particularly plastics may be used and the bags may be carrier bags or envelopes or otherwise as desired. Where the bag is a carrier bag an appropriate cut-out or cut-outs or other integral or attached arrangement may be provided to define a carrying handle. Where the bag is an envelope, a hinged flap may be provided.

The adhesive need not be in the form of stripes but may be applied as dots, lines or otherwise.

The folding of the bag to effect closure of the same need not be restricted to a flap at the mouth of same. For example, the bag shown in the drawing could be folded along the dotted line 20 in which case an adhesive stripe could be provided adjacent the bottom edge 21 (instead of the stripe 13), or stripes 22, 23 could be provided along the side edges (instead of the stripes 13, 14, 15). In the latter case each stripe is folded against itself.

The arrangement may be such that closure of the bag is only partially effected with the adhesive regions.

Further, whilst with the embodiment described the bag has front and back plies of single thickness alternative arrangements may be employed for example an arrangement involving an inner bag within and bonded to an outer bag.

Also, whilst with the embodiment specifically described the adhesive is applied prior to cutting the strip 2 from the web 1, if desired the adhesive may be applied after cutting of the strip 2 and prior to folding of same or even after the strip has been folded and glued. The invention is of course intended to be restricted to the formation of bags from flat continuous webs by cutting and glueing and instead bags may be formed from any suitable starting material, including continuous flat tubing, utilising any suitable assembly procedure including heat welding; and the adhesive may be applied at any suitable stage up to and including the final manufacturing stage of the finished bag.

Ciaims 1. A bag formed from superimposed plies of thin flexible sheet material and having an open mouth defined between adjacent peripheral portions of the plies, said bag having adhesive applied to at least one region of the outer surface of at least one of said plies thereof, whereby said bag can be folded so as to close said open mouth and bring the or each said adhesive region into engagement with at least one further region of the outer surface of at least one of said plies such as to form a bond therewith and thereby hold said open mouth closed.

2. A bag according to claim 1, wherein said adhesive is a pressure sensitive adhesive, said adhesive also being applied to the or each said further region.

3. A bag according to claim 1 or 2, wherein said adhesive is applied to the or each associated said region as a thin printed layer.

4. A bag according to claim 3, wherein said adhesive layer incorporates a printing ink.

5. A bag according to any one of claims 1 to 4, wherein said adhesive is applied to the or each associated said region as a stripe.

6. A bag according to any one of claims 1 to 5, wherein the or one first said region is an elongate region extending longitudinally of and adjacent to one said peripheral portion.

7. A bag according to claim 6 when dependent on claim 2 or on any claim dependent on claim 2, wherein the or one said further region is an elongate region extending longitudinally of and adjacent to said other peripheral portion, said two elongate regions being spaced from each other transversely such that at least one of said plies can be folded over at the said mouth to bring said elongate regions into contact with each other.

8. A bag according to claim 7, wherein one said elongate region is provided on a projecting flap integral with one ply.

9. A bag according to claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. A method of forming a bag according to any one of claims 1 to 8, wherein the application of the adhesive is effected by a printing technique using a printing roller which is fed with said adhesive in liquid or fluent form.

1 A method according to claim 10, wherein said bag is formed from a sheet cut from a continuous web, said sheet being folded and bonded to define a tubular structure having said superimposed plies, said application of adhesive being effected to one or more appropriate regions of said sheet prior to said folding and bonding of same.

12. A method according to claim 1 wherein said application of adhesive is effected prior to cutting of said sheet from said web.

13. A method according to claim 10 substantially as hereinbefore described with

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. mouth of the bag and bring the adhesive stripes on the two outer surfaces into contact with each other. The adhesive used is such that it quickly dries after initial application to the paper web 1 so as to become dry and non-tacky to the touch, but a bond is readily formed when the adhesive stripes are pressed into contact with each other. The bond may be of a permanent-nature or such that the adhesive stripes can be separated and rebonded together as and when desired. With the arrangement so far described, stripes of a very small amount of adhesive can be applied to the paper web using a technique and apparatus such as are conventionally used for printing decorative and/or informative matter on the web whereby the added cost and complexity involved in providing the bags with the stripes may be very small. It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only. Thus, for example, the invention is not restricted in application to paper packaging bags. Other materia!s, particularly plastics may be used and the bags may be carrier bags or envelopes or otherwise as desired. Where the bag is a carrier bag an appropriate cut-out or cut-outs or other integral or attached arrangement may be provided to define a carrying handle. Where the bag is an envelope, a hinged flap may be provided. The adhesive need not be in the form of stripes but may be applied as dots, lines or otherwise. The folding of the bag to effect closure of the same need not be restricted to a flap at the mouth of same. For example, the bag shown in the drawing could be folded along the dotted line 20 in which case an adhesive stripe could be provided adjacent the bottom edge 21 (instead of the stripe 13), or stripes 22, 23 could be provided along the side edges (instead of the stripes 13, 14, 15). In the latter case each stripe is folded against itself. The arrangement may be such that closure of the bag is only partially effected with the adhesive regions. Further, whilst with the embodiment described the bag has front and back plies of single thickness alternative arrangements may be employed for example an arrangement involving an inner bag within and bonded to an outer bag. Also, whilst with the embodiment specifically described the adhesive is applied prior to cutting the strip 2 from the web 1, if desired the adhesive may be applied after cutting of the strip 2 and prior to folding of same or even after the strip has been folded and glued. The invention is of course intended to be restricted to the formation of bags from flat continuous webs by cutting and glueing and instead bags may be formed from any suitable starting material, including continuous flat tubing, utilising any suitable assembly procedure including heat welding; and the adhesive may be applied at any suitable stage up to and including the final manufacturing stage of the finished bag. Ciaims

1. A bag formed from superimposed plies of thin flexible sheet material and having an open mouth defined between adjacent peripheral portions of the plies, said bag having adhesive applied to at least one region of the outer surface of at least one of said plies thereof, whereby said bag can be folded so as to close said open mouth and bring the or each said adhesive region into engagement with at least one further region of the outer surface of at least one of said plies such as to form a bond therewith and thereby hold said open mouth closed.

2. A bag according to claim 1, wherein said adhesive is a pressure sensitive adhesive, said adhesive also being applied to the or each said further region.

3. A bag according to claim 1 or 2, wherein said adhesive is applied to the or each associated said region as a thin printed layer.

4. A bag according to claim 3, wherein said adhesive layer incorporates a printing ink.

5. A bag according to any one of claims 1 to 4, wherein said adhesive is applied to the or each associated said region as a stripe.

6. A bag according to any one of claims 1 to 5, wherein the or one first said region is an elongate region extending longitudinally of and adjacent to one said peripheral portion.

7. A bag according to claim 6 when dependent on claim 2 or on any claim dependent on claim 2, wherein the or one said further region is an elongate region extending longitudinally of and adjacent to said other peripheral portion, said two elongate regions being spaced from each other transversely such that at least one of said plies can be folded over at the said mouth to bring said elongate regions into contact with each other.

8. A bag according to claim 7, wherein one said elongate region is provided on a projecting flap integral with one ply.

9. A bag according to claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. A method of forming a bag according to any one of claims 1 to 8, wherein the application of the adhesive is effected by a printing technique using a printing roller which is fed with said adhesive in liquid or fluent form.

1 A method according to claim 10, wherein said bag is formed from a sheet cut from a continuous web, said sheet being folded and bonded to define a tubular structure having said superimposed plies, said application of adhesive being effected to one or more appropriate regions of said sheet prior to said folding and bonding of same.

12. A method according to claim 1 wherein said application of adhesive is effected prior to cutting of said sheet from said web.

13. A method according to claim 10 substantially as hereinbefore described with

reference to and as illustrated in the accompanying drawing.

14. A bag when formed by the method of any one of claims 10 to 12.