NZ230818A - Bag with sleeve: inner surface of sleeve has higher melting point than outer surface - Google Patents

Description

230818 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL NO; 230818 DATED: 28 September 1989 IMPROVEMENTS IN AND RELATING TO THE MANUFACTURE OF A COMPOSITE BAG We, TRANSPAK INDUSTRIES LIMITED, of 23-25 Porana Road, Takapuna, Auckland, New Zealand, a New Zealand company, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: 230818 The present invention relates to the manufacture of a composite bag. The term "composite bag" is used throughout the specification as relating to a bag combining the function of a container with a sleeve which enables the bag to be filled and subsequently-emptied .

The term "bag" is itself used throughout this specification to relate to any form of container, particularly but not exclusively, to a large size container for use in a bulk packaging application. It is to be emphasized, however, that while large size composite bags may find particular use for the present invention, its use extends across all sizes of bags as the principles of the invention involved may have as much relevance for both small scale and large scale applications.

In bulk packaging, the large mouth openings of the ' large bags have created a problem in the filling and subsequent sealing of the bags. It is thus an object of the present invention to provide a composite bag, and a method of manufacturing same, which avoids or least obviates, the problems in bags available to the present time.

Further objects of this invention will become apparent from the following description. 230818 According to one aspect of the present invention, there is thus provided a method of forming a composite bag comprising, locating a sleeve having a longitudinal passageway therethrough which is open at both its ends, to extend across an opening in a bag, said sleeve being positioned so as to be withdrawable to provide a spout, further providing that said sleeve has at least an outer surface portion with a melting point substantially the same as that of the material of the bag in contact therewith and an inner surface portion with a melting point higher than that of said material of the bag whereby the provision of said inner surface portion enables the sealing of said bag about said sleeve so that the sealing of said opening does not seal off said passageway.

According to a still further aspect of the present invention, there is provided a composite bag comprising, a bag having an opening therein, a sleeve having a longitudinal passageway thereto which is open at both ends, said sleeve having a substantial portion extendable into said bag but being withdrawable therefrom so as to form an external spout, said sleeve further comprising an outer surface portion with a melting point substantially the same as that of the material of said bag in contact therewith, and an inner surface portion having a melting point which is higher than that of said material of said bag, said sleeve *. u f x -8 OCT 1992 <? 230818 being sealed within said opening of the said bag without the inner surface portion of said sleeve being sealed together to close off the passageway through the sleeve.

Further aspects of this invention, which should be considered in its novel aspects, will become apparent from the following description given by way of example of posssible embodiments thereof and in which reference is made with the accompanying drawings wherein: Figures 1 & 2: show diagrammatically side and end views of a composite bag according one possible embodiment of the invention as manufactured. 230818 Figures 3 & 4: show the composite bag of Figures 1 & 2 in use; Figures 1A, 2A 3A & 4A : show the composite bag according to a further embodiment of the invention with the same views as those shown in Figures 1, 2, 3 & 4 but in this embodiment with the gussets omitted; Figures 5 & 6: show diagrammatical ly side and plan views of a composite bag according to a further embodiment of the invention prior to the sealing of the sleeve in the bag opening; Figure 7: shows a plan view of the bag of Figures 5 and 6 after the sleeve has been sealed in the bag opening; Figures 8 & 9: show side and plan views of the composite bag of Figures 5 to 7 after the sleeve has been partially withdrawn and in Figure 9, after the sleeve has been sealed.

Referring initially to Figures 1 and 2 of the accompanying drawings, a composite bag according to one embodiment of the invention is referenced generally by arrow 1. The substantially elongate bag 2 is shown 230£i8 having a sealed bottom end 3 and side gussets 4 which, as shown by the dotted lines in Figure 1, may extend for the length of the bag 2. A sleeve 14 is shown positioned within the opening in the top of the bag 13, and between the gussets 4, so that in the position shown in Figure 1, a major portion thereof is internal of the bag 2 with a small portion 14A extending, in this example, above the top edge 13 of the bag 2.

In forming the composite bag 1, the opening across the top of the bag 2 is sealed off apart from the opening defined by passageway through the sleeve 14 between its open ends. A sealed area 12 is indicated provided adjacent to the top edge 13 as indicated by the double transverse lines thereacross.

In providing the seal 12 across the top end 13 of the bag 2, it is necessary to ensure that this does not at the same time close off the passageway through the sleeve 14.

To achieve this, a preferred embodiment of the present invention provides a multilayer structure for the sleeve 14 wherein it consists of at least inner and outer layers with the outer layer having a melting point which is approximately or substantially the same as that of the material of the bag 2 which contacts it, while the inner layer has a melting point which is higher than that of the material of the bag 2. By way of example, 230818 the material of the bag in contact with the outer layer and the outer layer itself of the sleeve 14 could be a polyolefin such as a polyethylene for example while the inner layer could be of a higher melting point material such as a polyamide, such as Nylon 6 for example.

While a polyolefin/polyamide multilayer structure for the sleeve 14 is given by way of example, numerous other multilayer structures will be apparent to those skilled in the plastics and materials arts. The important point is that any difference between the melting points of the bag material in contact with the sleeve and the outer layer of the sleeve does not prevent them being sealed together while still allowing the inner layer of the bag to remain unmelted. The term 'approximately or substantially the same' is used with this meaning in this specification and claims.

Turning now to Figures 3 and 4, the bag of Figures 1 and 2 is shown with the sleeve 14 withdrawn from the bag 2 so as to form a spout which can be used for filling the bag 2 with the desired material. It is seen therefore that the smaller opening provided by the sleeve 14 provides for a much more efficient filling of the bag 2, than would be the case if the large opening 13 of the bag 2 itself, before sealing, was used for this purpose.

It will be appreciated that in lifting the sleeve 14 to form the spout as shown in Figure 3 and as 2.308i8 indicated by the arrows A, the sleeve 14 has been turned effectively inside out or inverted so that the external or outer layer of the sleeve 14, of relatively low melting point, now becomes the internal layer for the inverted sleeve 14. In this way, a relatively low temperature sealing operation can be used so as to create a seal 11 across the top of the sleeve 14 after the filling operation has been completed and for this purpose, the same sealing equipment as was used initially to form the bag 1 can be used.

Furthermore, it is to be appreciated that when the contents of the bag are to be discharged, this can be achieved merely by the breaking of the seal 11.

It is also to be appreciated that as the spout in Figure 3 is created by the inverting of the sleeve 14, no protrusions are created on the inner surface of the sleeve 14 where it joins up with the bag 2 so that no obstructions are created to the flow of the material into or out of the bag 2. This also obviates the possible capture of material in such protruberances which could create a health hazard.

Referring now to Figures 1A, 2A, 3A and 4A of the accompanying drawings, a substantially similar embodiment of the invention is shown which in this case does not have the gussets 4 of the preceding figures. Otherwise, the formation and advantages of the bag 1 may be essentially the same. 81 y Turning now to Figures 5 to 9 of the accompanying drawings, a bag 110 is illustrated with an opening along its upper end 112. A sleeve 114 with a passageway therethrough and open at both its ends 116 and 118 is shown in Figure 6 inserted into the bag 110 through the opening 112 so that the major portion of the sleeve 114 is located inside the bag 110 but with a small portion which protrudes therefrom.

It will be seen particularly from Figure 6 that this embodiment of the invention is similar to that of the embodiment of Figures 1 to 4 but in this case the width of the sleeve 114 is such that the sides of the sleeve 114 extend so as to overlap the gussets 130.

Once again, a multilayer structure for the sleeve 114 provides at least inner and outer layers with the outer layer in Figures 5 having a melting point approximately or substantially the same as that of the material of the bag 110 itself in contact with it, with the inner layer of the sleeve 114 having a melting point which is higher than that of the material of the bag 110.

Thus, heat and pressure applied across the upper edge of the bag 110 along the zone indicated by 120 seals the outer layer of the sleeve 114 to the inner surface of the bag 110 in that zone 120 as well as sealing opposed inner surfaces of the bag 110 which are outside the sleeve 114. 230 As in the previous embodiments, this will seal the sleeve 114 inside the opening of the bag 110 but the o inner surfaces of the sleeve 114 would not be sealed together because of the higher melting point. The passageway through the sleeve 114 will thus still be open, providing a reduced opening compared to the pre-sealing opening 112 of the bag 110 itself.

Then, as seen in Figure 8 particularly, when the bag 110 is to be filled, the lower end 118 of the sleeve 114 can be withdrawn so as to protrude above the bag 110. After the use of the withdrawn sleeve 114 as a spout, the sleeve 114 can be sealed using the same sealing equipment as previously used for forming the bag 110. It is thus seen that the present invention in its various embodiments provides a composite bag which is formable with a substantially internal sleeve which upon inversion to extend outwardly from the bag may then be used for filling prior to sealing and subsequent reopening as and when discharge of the bag's contents is required. In a preferred embodiment of the invention, ' the multilayer structure for the sleeve has one layer with a melting point approximately or substantially the same as that of the material of the bag in contact with it, and an opposite layer has a melting point which is of higher value. This enables the initial formation of the bag and the subsequent sealing of the sleeve to be achieved with advantage using the same sealing equipment. 2308 - n - Where in the foregoing description reference has been made to specific components or integers of the invention having known equivalents then such eqpiivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications or improvements may be made thereto without departing from the scope or spirit of the invention, as defined in the appended claims. 230818

Claims (3)

WHAT WE CLAIM IS:

1. A method of forming a composite bag made of a plastics material comprising, locating a sleeve, having a longitudinal passageway therethrough which is open at both its ends, to extend across an opening in a bag, said sleeve being positioned so that a substantial portion of the sleeve extends into the bag, said sleeve having at least an outer surface portion with a melting point substantially the same as that of the material of the bag in contact therewith and an inner surface portion with a melting point higher than that of said material of the bag; sealing said bag opening about said sleeve whereby the higher melting point of said inner surface portion ensures that the sealing of said opening does not seal off said passageway and said sleeve portion extending into the bag is withdrawable from the bag to provide an external spout. •"--s

2. A method as claimed in Claim 1, in which said bag 'n.—/ and said outer surface portion of said sleeve are made of a polyolefin material and said inner surface portion of said sleeve is made of a polyamide.

3. A method of forming a composite bag substantially as herein described with reference to Figures lto ; o •>, i w >■' ^ ! - • ■ 230 8 1 - 13 - 4, Figures 1A to 4A or Figures 5 to 9 of the accompanying drawings. A composite bag when formed by the method of any one of the preceding claims. A composite bag made of a plastics material comprising a bag having an opening therein, a sleeve having a longitudinal passageway therethrough which is open at both ends, said sleeve having a substantial portion extending into said bag but being withdrawable therefrom so as to form an external spout, said sleeve further comprising an outer surface portion with a melting point substantially the same as that of the material of said bag in contact therewith, and an inner surface portion having a melting point which is higher than that of said material of said bag, said sleeve being Sealed within said opening of the said bag without the inner surface portion of said sleeve being sealed together to close off the passageway through the sleeve. *;A composite bag as ^laimed in Claim 5 where said;\;outer surface portion and said bag comprises a polyolefin material and said inner surface portion comprises a polyamide.;fcv";"'Vf;?.7) 0 8 1;- 13a -;7. A composite bag as claimed in either Claim 5 or Claim 6 wherein gussets are provided along each;2 1 DEC 1992r;I;r* .?3u8 i 8 14 side of the bag and wherein said sleeve extends longitudinally between said gussets. A composite bag as claimed in either Claim 5 or Claim 6 wherein gussets are provided along each side of the bag and wherein said sleeve overlaps said gussets. A composite bag substantially as herein described with reference with Figures 1 to 4, Figures 1A to 4A or Figures 5 to 9 of the accompanying drawings. BALDWIN, SON & CAREY Attorneys for the Applicant O g/specs/681980/sz