GB2210351A - Bag closure - Google Patents

Abstract

A bag, sack or the like is closed by folding-over material 31 of the open edge region of the walls of the bag 32 forming the mouth thereof to provide a folded-over closure to the bag mouth; and securing a closure tape (9, 17) to the folded-over closure and to a strip of the bag adjacent to the folded-over closure in such manner as to facilitate removal of the tape when it is required to open the bag. The tape and folded-over closure are passed between the nip of a pressure roller 36 and a stepped back up roller 35. The tape carries a heat activatable adhesive, and the lower section 38 of at least roller 36 has lands, so that the tape portion pressed by smooth section 37 of roller 36 is completely sealed and the tape portion pressed by section 38 is only partially sealed to provide a pull-strip. The adhesive is heat activated by heating the rollers, or prior to its insertion between the rollers. <IMAGE>

Description

BAG CLOSURE METHOD This invention relates to the closing of bags, sacks or other like containers.

In particular, the present invention is concerned with the closing of bags, sacks or other like containers which, when empty, fold flat and which open along an end or side edge.

Frequently, such bags, sacks or the like are initially formed as tubular lengths of which one end is closed prior to filling and the other end is sealed agaist any leakage of the content after filling.

Various methods and modes of closing such containers are known. For example, it is known to fold over, after the container has been filled with the requisite filling, the end or side having the container mouth or opening, and then to staple, sew, or glue the folded-over region thereby to seal the bag, sack or other container.

In practice, it has been found that these known forms of closing a container are frequently, bothersome to a person who needs to open the bag, sack or other container when it is required to remove the contents, in the sense that the containers sealed by the known methods are not always easy to open. This is often particularly the case when a knife or other tool is required for the opening operations.

It will be appreciated that a difficult situation can arise in the opening of containers which require a tool for the purposes of the opening operations and it is desired to empty the container into a location such as the inlet to a delivery or storage hopper which inlet is positioned such that the container has to be lifted away from the ground or other support before it is opened to avoid spillage of the content. In such circumstances it is of considerable importance from the point of view of the person handling the container that there should be no inpediment to the opening of the container such as would be caused by the need to use a tool or the like to open the container.

A further important factor arises in situations in which it is important to avoid dropping foriegn bodies or materials into the hopper or storage location. In this connection it has been found that when opening bags or containers involving sewn sealing arrangements or other arrangements which need to be cut or otherwise fragmentally removed to open the container it is readily possible for fragments of the sealing means such as threads or pieces of sealing material to fall into the hopper or storage means. It will be appreciated that any such foriegn body or material falling into the hopper, or storage means could be likely to contaminate end products or the like produced from the material being stored. For example, a fragment of string in a loaf of bread presuming that the material being stored is flour.

It is a object of the present invention to provide a method of and apparatus for closing a container of the kind generally mentioned above.

A further object of the present invention is to provide a method of and apparatus for the closure of bags or sacks which facilitates subsequent reopening of the bags or sacks.

According to a first aspect of the invention there is provided a method of closing a bag, sack or other like container including the steps of; folding-over material defining the edge regions of an opening to the container to provide a folded-over closure to the container opening ;and securing a closure tape to the folded-over closure and also to a strip of the body of the container adjacent to the folded-over closure by pasing the tape and folded-over closure through a pressure producing zone which acts upon the closure and the tape in such manner as to produce regions of lesser adhesion between the tape and the container as compared with the adhesion at other regions of the tape thereby to facilitate subsequent displacement of the tape when it is required to open the container.

Conveniently, differential pressure is applied to the tape container combination so as to accommodate any thickness differential of the container end to be sealed.

Conveniently, the method of attachment produces a pull strip or easier to remove region extending acrossgthe width of the container mouth.

Conveniently, the pull strip or easier to remove region is produced by securing the tape with regions of different adhesive strength, the arrangement being such that a region of lesser adhesive strength enables formation of the pull strip or easier to remove region.

According to a further aspect of the invention there is provided apparatus for closing an opening in a bag, sack or other like container, wherein means are provided for securing a tape to the container in such manner that the tape covers-in a folded-over closure to an opening in the container and also a strip of the body of the container adjacent to the folded-over closure, said securing means including a pressure producing zone which is arranged to act upon the closure and the tape so as to produce at least one region of lesser adhesion between the tape and the container in comparison with the adhesion at other regions of the tape, the arrangement being such as to facilitate subsequent displacement of the tape when it is required to open the container.

Preferably, the pressure producing zone is formed by the nip produced between a pair of rolls or rollers which are so adapted as to exert different pressures at different regions of the tape so as to produce said region(s) of lesser adhesion.

Conveniently, the mouth of the container is trimmed or otherwise controlled to define a precision edge region to the container, which edge region serves as a reference guide for subsequent folding and tape application operations.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which Figure 1 is a sectional view of a first stage in a first method of sealing of a bag in accordance with the proposals of the invention; Figure 2 is a sectional view of a second stage in the method sealing of the bag of Figure 1; Figure 3 is a sectional view of a final stage in the method of sealing of the bag of Figure 1; Figure 4 is a sectional view of a modified method of sealing a bag and in accordance with the proposals of the invention.

Figure 5 is a schematic sectional side view of a further modified closure arrangement for a bag, sack or other like contaioner; Figure 6 is a schematic fragmentary perspective view of a bag, sack or other like container when closed by the closure arrangement of the invention; Figure 7 schematically illustrates an embodiment of an adhesive tape which can be used in the arrangement of Figure 1, and illustrates a tape partially coated with adhesive; Figure 8 is a fragmentary sectional view illustrating the principles of operation of a pressure producing zone of apparatus for use in the bonding surfaces in accordance with the concepts of the invention; Figure 9 is a schematic oblique view of a second form of a pressure producing zone of apparatus for sealing a container and for applying a tape in accordance with the proposals of the invention.

Figure 10 is a schematic view of a further embodiment of a pressure producing zone of apparatus for applying tape to a container to be sealed, the view being taken across a transverse section of the container; Figure 11 is an oblique view of the apparatus of Figure 10, Figures 12A and 12B schematically illustrate in plan view alternative forms of a detail of the apparatus of Figures 10 and 11.

Referring now to the drawing and more particularly to Figure 1, the two side walls 1 and 2 of a bag or container 3 are brought as is conventional practice into contacting face-to-face relationship along the full width of the container and the marginal edge regions 1A and 2A of the container side walls are folded-over along a fold region generally shown at 4 into the position indicated in the Figure 1.

As will be noted the marginal edge region 1A is brought into contact with the adjacent part 1B of the associated side wall 1. It is useful to note that whilst it is not essential and in many cases not required, iat In the stage of the sealing of a container as shown in Figure 1 a seam or line of adhesive can be applied to the surface of the marginal edge 1A and/or the adjacent contacting region 1B of the container wall prior to the folding-over or even after the folding-over by introducing the adhesive between the facing surfaces 1A and 1B by any convenient means and the bringing such surfaces into contact. For convenience of explanation the adhesive seam has been shown in Figure 1 and indicated by the Reference numeral 5.

At the completion of this stage the folded-over region 1A/2A is folded-over once again about a fold region shown at 6 so that the position as shown in Figure 2 is reached.

As will be noted the marginal edge region 2A is brought into face-to-face relationship with a region 1C of the side wall 1, thereby producing a folded over region 7 of triple thickness of folded over container forming material material and thus a region of six side-by-side layers of bag wall material. It is to be noted that the term layer is intended to embrace container forming material made-up from several plies or thinner thicknesses of material.

If it is considered necessary a seam or line of adhesive can be introduced by any convenient means, between the face 2A and the adjacent wall region 1C.

For ease of explanation such a seam or line of adhesive has been shown in Figure 2 and identified by the reference numeral 8.

At the completion of this double fold-over procedure, as may be seen from Figures 3 and 4 the folded-over part is conveniently regarded as a folded-over closure and this closure is at least partly enclosed or shrouded by a strip of tape 9 which extends fully lengthwise of the folded-over region and encloses at least the entrance 9A defined by the folded-over closure 7 in conjunction with the adjacent outer surface of the container wall. Figure 3 illustrates a totally enclosing tape 9 and Figure 4 a partially enclosing tape formation.

The tape 9 is secured to the container and can be of such width that when secured to the folded-over closure region the marginal edge regions 10 and 11 of the tape extend a short distance down each face of the as container shown in Figure 3. The free edges of these regions 10 and 11 may be offset relative to each other or level with each other. In the Figure 4 arrangement the width of the tape 9 is such that it is located totally to one side of the container. The Figure 4 illustrates the folded-over region without a seam or line of adhesive being used.

The tape 9 can be of the kind which is self adhesive, which can be attached by applying a suitable adhesive by any convenient means or which is heat activatable.

It will be appreciated that in the absence of the seam(s) or line(s) of adhesive 5 and 8 between the double folded-over closure regions of the container, the container is held in the closed condition by the provision of the tape 9.

In practice, it has been realised that it would be convenient to be able easily to remove the tape to facilitate the actual opening of the container.

To this end Figures 5, 6 and 7 of the drawings relate to proposals for securing of the tape 9 to the container in such manner as to facilitate the removal of the tape. As may be seen the mouth or open end 1 of a bag, sack or other like container 3 is double folded to form the folded-over closure as previously discussed.

The tape 9 extends for the full width of the container 3 so as fully to enclose the entrance 9A.

The tape 9 of Figure 5 can conveniently be regarded as involving four distinct regions. A first region 12 which is secured by adhesive to the outer surface of the outer folded-over portion, a second region 13 which is secured by adhesive to a strip of the container body running parallel to the entrance 9A, a third region 14 bridging the said entrance 9A, and a fourth region 15 which may be conveniently regarded as a pull strip or easier to remove region for facilitating the removal of the tape 9.

The adhesive that is applied to the tape 9 is such that it is of a sufficient strength as to retain the folded-over closure in its folded-over container closing state, but not of sufficient strength as to resist the peeling of the tape 9 away from the container 3 when it is required to open the container.

The method for the application of the adhesive applied to the tape 9 may take various forms. For example, the adhesive may be applied to the regions 12 and 13 or to the regions 12, 13 and 14 leaving the region 15 uncoated with adhesive.

Alternatively, the adhesive may be applied to the full width of the tape 9 and the pull strip region 15 formed by folding the tape along a marginal edge portion thereof to produce a non-adhesive region which serves as the pull strip 15.

Figure 6 is very schematic view of a container when sealed by the arrangements of the present invention.

Figure 7 provides an indication of a possible mode of applying adhesive to the tape 9. The Figure is intended very schematically to illustrate a tape which has been partially covered with the adhesive in the sense that the total surface area of the tape is not covered with adhesive.

In order to open the container when closed by the application of a sealing tape it is merely necessary to exert pull on the pull strip 15 generally in the direction of the arrow 16 sufficiently to cause the tape region 13 to separate from the container but not sufficient to pull the tape 9 away from the folded-over closure region. Once the strip region 13 has thus been separated from the container the folded-over closure of the container mouth can be unfolded and the container opened.

It will be noted that throughout these opening operations the tape remains securely attached to the container and that no material detrius or fragments are produced which could lead to the dropping of foriegn bodies into the location into which the content of the container is discharged.

Furthermore, it will be understood that the particular nature of the adhesives used will be chosen according to the material or materials used for the container.

Referring now to Figure 8 this shows in cross section a tape 17 that is required to be secured to a surface 18 of a wall 19 of a bag or other container adjacent an open end thereof. The tape 17 is provided with a coating or layer 20 of an adhesive which needs to be heat activated in order to render the layer adhesive.

With such an adhesive only those portions thereof that are heated to a temperature at which the adhesive is activated can be caused to adhere by the application of pressure to a second surface.

Since it is required, for example, to so attach the tape 17 to the surface 18 that at least one predetermined region or portion of the tape 17 is or are readily removable only preselected areas of the adhesive on the tape are subjected to combined heating and pressure. For example, in the arrangement shown it is assumed that the preselected areas at which adhesion is required comprises three strips 21, 22 and 23 aligned parallel to each other and running lengthwise of the tape.

The tape 17 with the activated adhesive and the wall 19 to be bonded are together passed through the nip between two rolls or rollers 24 and 25 which are rotatable about axes parallel to each other. The roll or roller 24 is provided with three circumferential spaced lands 26, 27 and 28 which are spaced apart by a distance equal to the spacing required between said strips 21, 22 and 23 of required firm adhesion of the tape 17 to the surface 18. The strips of the tape located between the lands are not subjected to the same pressure so that these strips provide the strips of lesser adhesion.

The rolls or rollers form the pressure producing zone part of apparatus which incorporates arrangements for the physical handling of the containers and the tape, for presenting the tape to to the container, and for feeding the container tape combination to and through the pressure producing zone. Since this specification is essentially concerned with the operation of the pressure producing zone it is thought th-at a detailed discussion of other parts of the remainder of the apparatus is not necessary.

The roll or roller 25 has a smooth surface and is merely intended to act as a pressure roll or roller with respect to the roll or roller 24.

The arrangements provided for activating i.e., heating, the adhesive are not shown. Such heating can be effected by, for example, passing the container plus the tape 9 through a pre-heating stage and then through the nip of the roller or roll pair 25 and 26, thereby to subject the activated i.e., preheated adhesive to the necessary firm sealing pressure where a firm of full sealing is desired and to apply lesser presser where regions of lesser adhesion are desired.

That is to achieve the full sealing at the the strips 21,22 and 23 only these strips are subjected to the required combination of activation and full pressure.

Alternatively, the heating' can be effected at the actual pressure zone. In this case arrangements (not shown) are provided for heating the roll or roller 25 such that rolls and rollers and particularly the lands 26, 27 and 28 attain a temperature which, on passing the tape and material 18 through the aforesaid nip, will cause adequate activation of the strips 21, 22 and 23 of adhesive immediately opposite the lands 26, 27 and 28.

Following activation of the adhesive the combination of the adhesive activation and the action of the pressure roll or roller 25, the tape 17 becomes fully bonded to the surface 18 along the strips 21, 22 and 23 once the previously activated adhesiye has cured or otherwise set following its removal from the effects of the heated roll or roller.

The tape is held firmly in place only by the three strips 21, 22 and 23 of bond defined by the previously activated adhesive.

Consequently, the holding power of the bonding will be correspondingly less than would be the case if the total surface area of the tape had been firmly bonded to the surface 18, whereby the subsequent removal of the tape to allow opening of the bag is facilited.

In practice, the particular arrangement of the regions of bond can be selected as required by suitable patterning of the working surface of the heated roll or roller 24.

In the arrangement of Figure 9 the roll or roller 24 is provided with a 'diamond' pattern of raised lands 28 which extend over a predetermined axial length of the roll or roller. In practice, the pattern of adhesive activation corresponds on a one-to-one relation-ship to the form of the pattern provided upon the roller. As has been mentioned the adhesive can be preactivated i.e., by heating prior to entering the nip between the pressure producing rollers or rolls.

Alternatively the latter mentioned rollers or rolls can be arranged to cause the activating heating.

Whilst the Figures indicate that only one side of the tape 17 is secured by the use of selected regions of the adhesive layer. If required, in the case where the tape bridges as has been schematically illustrated in the Figure the open end region of a bag both rolls or rollers could be patterned. The patterning of the two rolls can be similar or different as thought convenient. It will be understood that what ever the combination of patterned roll or roller and the pressure roll or roller it is important to ensure that adequate sealing pressure is exertable in the nip over the regions in which firm adhesion is required.

Furthermore, if required, the heating of the tape can be such that the adhesive provided on a first region of the tape that is to be secured to a first surface is activated over the whole area of said first region, and that the adhesive elsewhere on the tape is activated at selected regions only, in the manner discussed hereinbefore, when securing the tape to a second surface. With this arrangement the tape will be firmly attached to the first surface whereby the tape remains adhered to the first surface when the tape is pulled away from the second surface.

It has been found that when it is required to seal containers the formation of the folded-over closure produces multilayers of material over a part of the region at which it is required to secure the tape the consequence of which difficulties have been found to arise in that when using rolls such as shown in Figures 8 and 9 in that differential sealing pressures are produced at various regions of the tape irrespective of the pressure differences required to produce the required regions of firm bond.. This will be appreciated by consideration of Figures 3 and 4.From Figure 3 it will be noted that for the upper portions 9 and 11 of the tape there are six layers of container material and the two layers 9 and 11 of tape, whilst in the Figure 4 arrangement at the upper part 9 of the tape there are six layers of container material and one layer 9 of tape; whereas in each case at the lower part of the tape 10 there are only two layers of container material and one layer of tape. As a result a material thickness differential is produced at the regions of tape attachment. The above situation is likely to be compounded in cases where the container has gussets at its ends since the formation of such gussets produces an additional six layers of material.

It will be appreciated that if the ccontainer end is further folded to provide a triple fold the resulting thickness differential is even greater.

A consequence of this thickness differential is that, in practice, if sealing rolls are set to achieve optimum sealing pressure at the thicker material region discussed above the sealing pressure at the thinner material thickness i.e., at the lower tape part may well be totally inadequate thereby resulting in a inadequately sealed container.

Bearing in mind that a variety of thicknesses of materials are used for forming containers it will be appreciated that the quality of sealing may well vary accordingly.

It is a further feature of the present invention to provide in apparatus for securing the tape to the container a roll or roller pair combination for exerting the requisite pressure to the activated tape adhesive for firmly securing the tape at the regions at which firm sealing is required and which is adapted for accommodating differential thickness of a container being sealed.

Referring now to Figures 10 and 11 these illustrate an embodiment of the apparatus of the invention which is able to accommodate the differential thickness as above mentioned, The Figures illustrate a double folded container end 31 and associated tape 32 to be applied thereto for the purposes of sealing the container end located between the nip 33 of a roll pair 34 including a back-up roll 35 and a pressure roll 36.

Arrangements are provided for the heat activation of the tape prior to its engagement with the roll pair 34 to a temperature at which heat sensitive adhesive applied to the tape 32 is activated sufficiently to become adhesive and able as a result of the combined heating and applied pressure of the roll pair 34 to attach the tape 32 to the container end 31.

As an alternative, mode of activation arrangements (not shown) can be provided for heating the roll pair for the purposes of effecting the heat activation.

The pressure roll 36 can be considered as including a top section 37 and a bottom section 38.

The two sections are mounted for rotation on a common shaft (not shown). The back-up roll 35 has a stepped formation in that the diameter of the portion 39 thereof cooperable with the upper section 37 of the pressure roll 36 has a smaller diameter that that of the lower portion 40 thereof that is intended to coperate with the lower section 38 of the pressure roll.

The difference in the diameters of the portions 39 and 40 is selected so as to accommodate the above mentioned differential thickness of the folded-over closure end 31 of the container.

In practice, provision may be made for having interchangeable back-up rolls 35 so that the diameter differentical can be selected according to the expected thickness of the container folded end region.

The construction of the pressure roll determines the nature of the sealing of the tape onto the container.

Thus, for example, when it is desired to provide for the differential adhesion i.e., to provide for an easy peal i.e., lesser adhesion strip as above discussed the lower section 38 of the pressure roll 36 can incorporate a plurality of axially directed lands 41 equiangularly disposed around the circumference of the roll 36 so that the roll has a castellated construction as schematically shown in Figure 12A.

With this construction in which the roll lower section 38 presents to the tape 32 axially directed pressure producing strips so that the amount of adhesive subjected to the full pressure per roll revolution is set by the circumferential length of the lands. In other words the degree of full or firm adhesion can be determined by the circumferential length of the lands, the number of lands provided and the relative positioning of the lands around the circumference of the roll. It will be appreciated that whilst the Figure shows lands of the same size and spacing if desired the separation and or circumferential length can be varied as thought convenient for any particular application of the apparatus.

As it is usually required to provide a total seal at the actual folded over thicker part of the container end the pressure roll upper section will present a plane surface to the tape.

It will be appreciated that the relative relationships between the relative extents of total seal and partial seal can be set by suitable selection of the profiling of the surfaces of the upper and lower sections of the pressure roll.

Thus, for example, if a firm seal is required for all of the tape, the pressure roll will have a plane surface as is indicated in Figure 12B.

It has been found, in practice, convenient to coat the pressure roll or roller 36 with a layer of silicon containing elastomeric material such as silicon rubber.

This has been found to to provide the roll or roller 36 with a degree of resiliency which enables local variations in container thickness to be accomodated during the passage thereof through the nip of the rolls or rollers.

Whilst the above description has specifically referred to a pressure producing zone utilising the nip between a pair of rolls or rollers as the pressure producing means it will be appreciated that linear cramping arrangements could be adopted if considered more appropriate to the sealing of particular container constructions.

Claims (23)

1. A method of closing a bag, sack or other like container including the steps of; folding-over material defining the edge regions of an opening to the container to provide a folded-over closure to the container opening; and securing a closure tape to the folded-over closure and also to a strip of the body of the container adjacent to the folded-over closure by passing the tape and folded 7 over closure through a pressure producing zone which acts upon the closure and the tape in such manner as to produce regions of lesser adhesion between the tape and the container as compared with the adhesion at other regions of the tape thereby to facilitate subsequent diaplacement of the tape when it is required to open the container.

2, A method as claimed in claim 1, and wherein the folded over closure to the container and the tape are passed through the nip of a pair of rolls or rollers which exert different pressures at different regions of the tape to produce said regions of lesser adhesion between the tape and the container.

3. A method as claimed in claim 1 or 2, wherein the adhesive is activated before being subjected to pressure produced by the pressure producing zone.

4. A method as claimed in claim 1 or 2, wherein the adhesive is activated simultaneously with the application of said pressure.

5. A method as claimed in claim 1, 2, 3 or 4, wherein the activation is produced by the application of heat to the adhesive.

6. A method as claimed in claim 1, 2, 3, 4 or 5, wherein the pressure exerted on the tape is such as to establish at least one strip of lesser adhesion, and wherein each such strip extend(s) lengthwise of the tape, the arrangement being such that the lesser adhesion associated with each such strip facilitates said displacement of the tape for the purposes of opening the container.

7. A method as claimed in claim 6, wherein a said strip of lesser adhesion is located adjacent a free longitudinal edge of the tape, the arrangement being such that this strip of lesser adhesion forms a pull strip which is easier to remove from the container than the remainder of the tape.

8. A method as claimed in claim 1,2,3,4 or 5, wherein the pressure exerted on the tape is such as to establish a plurality of spaced apart panels of lesser adhesion, said panels extending transversely of the length of the tape.

9. A bag, sack or like container when sealed by the method as claimed in any of claims 1 to 8.

10. Apparatus for closing an opening in a bag, sack or other like container, wherein means are provided for securing a tape to the container in such manner that the tape covers-in a folded-over closure ' to an opening in the container and also a strip of the body of the container adjacent to the folded-over closure, said securing means including a pressure producing zone which is arranged to act upon the closure and the tape so as to produce at least one region of lesser adhesion between the tape and container in comparision with the adhesion at other regions of the tape, the arrangement being such as to facilitate subsequent diaplacement of the tape when it is required to open the container.

11. Apparatus as claimed in claim 10, wherein the pressure producing zone is formed by the nip produced between a pair of rolls or rollers which are so adapted as to exert different pressures at different regions of the tape so as to produce said region(s) of lesser adhesion.

12. Apparatus as claimed in claim 10 or 11, and including means for activating the adhesive used to bond the tape to the container prior to the tape being subbjected to pressure by said pressure producing means, the arrangement being such that the adhesive is pre-activated before being subjected to pressure.

13. Apparatus as claimed in claim 10 or 11, wherein means are provided for activating the adhesive simultaneously with the application of said pressure.

14. Apparatus as claimed in claim 10, 11,12 or 13, wherein the activation of the adhesive is produced by the application of heat to the adhesive.

15. Apparatus as claimed in claim 10 ,12, 13 or 14, wherein the means for exerting pressure upon the tape is adapted so as to establish at least one strip of said lesser adhesion extending lengthwise of the tape.

16. Apparatus as claimed in claim 15, wherein the pressure exerting means is arranged to form a said strip of lesser adhesion adjacent a free longitudinal edge of the tape, the arrangement being such that this particular strip strip of lesser adhesion forms a pull strip which is usable for facilitating the displacement of the tape.

17. Apparatus as claimed in claim 10, 11, 12, 13 or 14, wherein the pressure exerting means is such as to establish a plurality of spaced apart panels of said lesser adhesion said panels extending transversely of the length of the tape.

18. Apparatus as claimed in any of claims 10 to 17, wherein the pressure producing zone includes a pair of rolls or rollers defining a nip through which the surfaces to be bonded can be passed, and wherein one or both of the rolls or rollers is/are provided with at least one surface defining a region or regions which are effectively raised relative to the remainder of the surface of the roll or roller, the arrangement being such that whenever a raised region passes through said nip and thus cooperates with a region of the tape at which the adhesive is activated the tape is caused firmly to adhere to the container, and wherein whenever any portion of said remainder of the surface passes through the nip the pressure produced upon the tape is such that a said region of lesser adhesion is formed.

19. Apparatus as claimed in claim 18, wherein said raised regions are directed transversly of the axis of rotation of the associated roll or roller, the arrangement being such that the raised portions exert pressure longitudinally of the strip the arrangement being such that the regions of lesser adhesion are directed longitudinally of the tape.

20. Apparatus as claimed in claim 18, wherein said raised regions are directed axially of the associated roll or roller, the arrangement being such that the raised portions exert pressure on transverely directed spaced apart regions of the tape whereby the regions of lesser adhesion are also directed transversely of the tape.

21. Apparatus as claimed in claim 18, 19 or 20, wherein when the adhesive being used to bond the tape to the container is heat activatable means are provided for preheating the adhesive prior to the engagement of the tape with the rolls or rollers.

22. Apparatus as claimed in claim 18, 19 or 20, wherein when the adhesive used to bond the tape to the container is heat activatable means are provided for heating the roll(s) or roller(8) whereby the adhesive is activated during . the passage of said surfaces to be bonded through the rolls or rollers.

23. Apparatus for closing an opening in a bag, sack or the like, substantially as hereinbefore described with reference to Figure 8, 9, 10, 11, 12A or 12B of the accompanying drawings.