GB1571938A

GB1571938A - Patch top container and closure assembly and method of making the same

Info

Publication number: GB1571938A
Application number: GB16257/77A
Authority: GB
Original assignee: Boise Cascade Corp
Current assignee: Officemax Inc
Priority date: 1976-06-07
Filing date: 1977-04-19
Publication date: 1980-07-23
Also published as: FR2353456B1; DE2647775C3; IT1065375B; MX144577A; DE2647775A1; NL7610080A; DE2647775B2; FR2353456A1; AU1801676A; CA1095459A; SE7610553L; BR7606652A; LU77044A1; BE852916A; DK474776A; AU511659B2; JPS52150183A

Description

(54) PATCH TOP CONTAINER AND CLOSURE ASSEMBLY AND METHOD OF MAKING THE SAME (71) We, BOISE CASCADE CORPORATION, a corporation organised under the laws of the State of Delaware, United States of America, of One Jefferson Square, Boise, Idaho 83728, United States of America, 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:- This invention relates to containers, more particularly patch top containers and also to a method of closing the open end of a container.

Patch top containers and methods of making the same are well known. Usually the end of a container (which is normally of the composite type including layers of paperboard, foil, synthetic plastic material or the like) is closed by a relatively thin patch top member (normally formed from aluminium foil or the like). The patch top member is bonded to the container end (for example, by a heat sealable membrane, a hot melt adhesive, an ethylene vinyl acetate adhesive, or the like) to afford an hermetically sealed container.

A reusable synthetic plastic overcap is then provided for protecting and maintaining in place the patch top member. As is conventional in the art, pull tab means are provided on the patch top members so that when the plastic overcap is removed to expose the patch top, the pull tab portion of the patch top member may be manually grasped by the user to remove the patch top from, and thereby open, the container.

The patch top member is then discarded, and the packaged contents may be removed from the container. If desired, the container may be reclosed by the reapplication of the plastic overcap to the container.

According to the present invention there is provided a patch top container and closure assembly comprising a container body formed with an outwardly extending collar surrounding an opening at one end thereof and a closure for said opening comprising an impervious patch top member extending transversely across said one end of the container; a first adhesive layer hermitcally but releasably bonding the patch top member with said one end of the container body, an overcap member extending transversely across said container with an inner surface of said overcap member contiguous with an outer surface of said patch top member, a second adhesive layer securing together said contiguous surfaces of said patch top member and said overcap member, said second adhesive layer producing a stronger bond between said patch top member and the overcap member than that produced by said first adhesive layer between said patch top member and the container body, and means releasably coupling said overcap member with said container, whereby when said overcap member is removed from the container the hermetically sealed bond between the patch top member and the container is automatically broken and access is afforded to the interior of the container, whereafter the overcap may be reapplied to sealingly close the container.

The invention also provides a reusable closure for closing the open end of a container comprising a reusable closure for closing the open end of a container, comprising an impervious patch top member having thereon a first adhesive layer by means of which in use, the patch top member makes a releasable hermetic seal to the extremities of the walls of the container open end, said patch top member being bonded to the interior of an overcap member by means of a second adhesive layer producing a stronger bond between said patch top member and said overcap member than that produced by said first adhesive layer between said patch top member and said container walls, whereby when the overcap member is removed from the container the hermetic seal between the patch top member and the container walls is automatically broken, the overcap member having means thereon for maintaining it upon the container after said hermetic seal has been broken.

The present invention was developed to provide an improved patch top container and closure assembly including closure means that are initially in a bonded condition to provide an hermetically sealed closure for the container, and which are subsequently operable to afford means for reclosing the container. Thus the patch top member is bonded to the plastic overcap for simultaneous removal therewith. In this manner, the possibility of undesirable litter normally produced by the removal of the patch top member is eliminated, and since the patch top member is always protected and/or supported by the overcap member, it may be formed of a thinner gauge aluminium foil, whereby the cost of the resulting container is reduced. Furthermore, the necessity of providing pull tab means on the patch top member and the manufacturing and assembling considerations resulting therefrom are elminated.

Conveniently, the overcap member is a synthetic plastic material and includes a central portion which extends slightly into the container end, and an intermediate portion containing an annular groove or recess which has a configuration which conforms generally to the inner circumferential surface of the container end. The patch top member has a transverse central portion which is axially displaced from the extremity of the container end, and an annular peripheral portion which is pressed in conforming relation against the inner circumferential surface of the reversely curled portion of the container end.

The closure means is particularly suitable for applications to a container of the composite container type including a fibrous body wall layer and at least one impervious liner layer, the end of the container being reversely outwardly curled to define a collar or curled end portion. For such applications, the overcap member may include an annular flange portion that extends concentrically about the container end portion, said flange portion carrying on its inner surface locking means which engage the container curled portion to retain the overcap on the container, and also to bias the overcap intermediate portion in a direction causing conforming engagement of the patch top peripheral annular portion with the inner end surface of the container.

Tamper-proof means for resisting the removal of the overcap member from the container may be provided such as a conventional shrink tape member which is shrunk-fit about the outer circumference of the end portion of the container across the juncture between the free end of the flange portion of the overcap and the adjacent outer surface of the container.

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a detailed side elevational view of one form of composite container provided with a patch top closure; Figures 2 and 3 are side elevational and top plan views of the synthetic plastic overcap member of the ernbodiment of Figure 1; Figure 4 is a detailed sectional view taken along line 4-4 of Figure 2; Figure 5 is a detailed sectional view of a modification of the container of Figure 1; and Figure 6 is a detailed sectional view of a second modification of the container of Figure 1.

Referring now more particularly to Figure 1, the container includes a tubular composite body 2 having a fibrous body wall 2a to the inner and outer surfaces of which are bonded impervious inner and outer liner layers 2b and 2c, respectively, which are normally formed from relatively thin gauge aluminium foil. The open end of the container body wall is reversely curled to define curled end portion 2d.

Seated across the open end of the container body wall 2 is a patch top member 4 which is of a uniform diskshaped configuration (i.e. without the pulltab means normally provided on such patch top closure members). The patch top member normally includes a layer 4a of aluminium foil the inner and outer surfaces of which are coated with first and second layers of adhesive means 4b and 4c, respectively.

Mounted in protective relation upon the end of the container 2 above the patch top member 4 is an overcap member 6 which is preferably formed of a synthetic plastics material. The plastics overcap member 6 includes a central portion 6a which extends slightly within the container body wall 2, an intermediate portion 6b which contains a concave recess 8 for receiving the curled end portion 2d of the container, and a flange portion 6c that extends concentrically about the container end. As shown in Figure 1, the central portion 6a of the plastics overcap causes displacement of the central portion 4d of the patch top member axially within the container. The inner wall surface of the recess of the intermediate portion 6b of the plastics overcap conforms generally with and is spaced from the configuration of the reversely curled end portion of the container body 2.Thus, annular peripheral portion 4e of the patch top is caused to conform with the inner circumferential end portion of the container 2 by the curved wall portion of the recess 8 contained in the intermediate portion of the plastic overcap. Furthermore, in order to maintain the plastic overcap on the container, the flange portion 6c of the overcap member is provided on its inner surface with an annular locking rib 6d which extends in snap-fit relation beneath the lower extremity of the container curled end portion 2d.Preferably the cavity or recess 8 is so dimensioned that the locking of the rib 6d beneath the curled portion 2d causes the application of a biassing force in the direction indicated by the arrow F, which biassing force causes the peripheral annular portion 4e of the patch top member 4 to be maintained in conforming engagement with the corresponding surface on the container end.

The second adhesive layer 4c for bonding the patch top 4 to the overcap 6 is stronger than the first adhesive layer 4b which adhesively bonds in an hermetically sealed manner the patch top member 4 to the container 2. Thus, the second adhesive layer 4c is selected which has a relatively high bonding strength, as for example, a heat-sealable layer of polyethylene, or the like. The first adhesive layer 4b is selected having a relatively low bonding strength, as, for example, a peelable hot melt adhesive, a layer of ethylene vinyl acetate, or a suitable pressure-sensitive adhesive layer. Although the first adhesive layer 4b has been illustrated as extending continuously across the inner surface of the patch top member, if desired it could be provided only adjacent the annular peripheral portion 4e of the patch top.In either case, the first adhesive layer provides an hermetic seal for the container for the container contents.

In order to assist in the removal of the plastic overcap, there is provided a pull tap portion 6e which extends downwardly from the flange portion 6c longitudinally of the container, said pull tab portion containing an opening 6f. In order to resist removal of the plastic overcap from the container, tamper-proof means in the form of a shrink-fit tape 10 are provided, said tape being wound circumferentially about the container across the junction between the flange portion 6c of the overcap and the body wall 2 of the container, said shrinkfit tape including a pull tab portion 1 0a for the removal thereof from the container.

The shrink-fit tape is well known in the art and as it does not form part of the invention it will not be described further here.

Referring to Figures 2-4, it will be seen that the synthetic plastic overcap member which is preferably formed from low density polyethylene or the like-is of flexible unitary molded construction. If desired, the upper surface of the plastic overcap member may be provided with radially extending reinforcing ribs 6g. It will be apparent from Figure 4 that the recess 8 contained in the intermediate portion 6b of the plastic overcap 6 has a configuration to conform with that of the curled end portion 2d of the container body 2.

In operation, to open the container package of Figure 1, the pull tab portion 10a of the shrink-fit tape 10 is pulled to remove the tape from the container package, whereupon the tab portion 6e of the plastic overcap is lifted to pull the overcap member 6 upwardly from the container. During this removal of the plastic overcap member, the weaker adhesive bond 4b between the patch top 4 and the conforming portion of the inner circumferential surface of the container end portion 2d is broken, so that the patch top 4 is removed from the container 2 simultaneously with the removal of the plastic overcap member 6. The contents may then be removed from the container 2.In the event it should be desired to reclose the container, the plastic overcap member 6-with the patch top member 4 secured thereto-is reapplied to the container 2 in the illustrated position with the locking rib 6b again extending in snap-fit relation beneath the curled container end portion 2d.

It is possible, of course, to further prevent litter by forming the removable shrink-fit tape 10 from a suitable biodegradable material, as is known in the art.

Referring now to the alternate embodiment of Figure 5, it will be seen that the shrink-fit tape 10' may extend at its upper extremity 10a' over onto the upper marginal portion of the plastic overcap member 6, thereby to more positively secure the overcap member to the composite body wall 2.

The end portion of the composite container is reversely outwardly curled in a conventional manner. The patch top member 4 having the adhesive layers 4b and 4c thereon is preferably introduced into the plastic overcap (for example, during the punching operation by which the patch top member is formed from an aluminium foil sheet) and to the end of the container with the locking shoulder 6d extending in snap-fit relation beneath the lower extremity of the container reverse curl 2d. Thus, the central portion 4d of the patch top is displaced axially within the container and the peripheral annular portion 4e of the patch top is caused to conform with the inner circumferential surface of the curled end portion 2d of the container body member 2.The end of the container is then heated (for example, by conventional ultrasonic, induction or dielectric heating techniques) to effect bonding of the patch top member to the container and to the overcap member by the heat-responsive layers 4d and 4c, respectively. Thus, in the case where the second adhesive layer 4d comprises a layer of conventional hot melt material arranged at least on the peripheral annular portion of the patch top, the layer is softened by the application of heat to effect a bond between the patch top member and the container which is weaker than the bond between the patch top and the plastic overcap member.The shrink-fit tape 10 is then wound upon the container, and the container is passed through a separate oven to effect shrinking of the tape in tight engagement across the juncture between the lower edge of the flange portion 6c and the outer surface of the container body. The overcap member is thus connected against inadvertent displacement relative to the container.

Of course, various means may be provided for applying the first and second layers of adhesive. For example, the second layer of adhesive 4d could be coated on the inner circumferential surface of the reversely curled portion 2d prior to the mounting of the patch top 4 upon the open end of the container. Furthermore, it might be desirable to bond the patch top member 4 to the plastic overcap member 6 prior to the assembly of the plastic overcap 6 upon the curled end portion 2d of the container 2.

Finally, as shown in Figure 6, the central portions of the overcap and patch top members 6 and 4', respectively, may be flat and horizontal, the patch top member extending in contiguous engagement across the upper extremity of the reversely curled container end.

It will be appreciated from the foregoing that the invention provides closure means for closing the reversely curled end of a composite container, including a synthetic plastic overcap member which is removably connected with the container and is adapted to be reapplied to the container to reclose the end thereof. The patch top member is arranged between the container and the overcap member, the patch top member being bonded to the container by a weaker first adhesive material to define an hermetic seal, and to the overcap member by a stronger second adhesive, whereby upon removal of the ovrecap member, the bond of the first material is broken and the patch top member is moved simultaneously with the overcap member. Anti-tampering means, such as a shrink-fit tape, may be provided with either embodiment to reduce the possibility of inadvertent removal of the overcap member.

WHAT WE CLAIM IS: 1. A patch top container and closure assembly comprising a container body formed with an outwardly extending collar surrounding an opening at one end thereof and a closure for said opening comprising an impervious patch top member extending transversely across said one end of the container; a first adhesive layer hermetically but releasably bonding the patch top member with said one end of the container body, an overcap member extending transversely across said container with an inner surface of said overcap member contiguous with an outer surface of said patch top member, a second adhesive layer securing together said contiguous surfaces of said patch top member and said overcap member, said second adhesive layer producing a stronger bond between said patch top member and the overcap member than that produced by said first adhesive layer between said patch top member and the container body, and means releasably coupling said overcap member with said container, whereby when said overcap member is removed from the container the hermetically sealed bond between the patch top member and the container is automatically broken and access is afforded to the interior of the container, whereafter the overcap may be reapplied to sealingly close the container.

2. An assembly as claimed in claim 1, wherein the patch top member extends across and is in contiguous engagement with the margin of said one end of the container.

3. An assembly as claimed in claim 1 or 2, wherein said overcap member is formed of a thermoplastic synthetic plastics material.

4. An assembly as claimed in any one of the preceding claims wherein said overcap member is flexible and further includes a pull tab portion that extends downwardly from the overcap member adjacent the outer surface of the container body.

4. An assembly as claimed in any of the preceding claims wherein the surface of the overcap member remote from said one end of the container body is provided with a plurality of radially arranged strengthening ribs.

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

Claims

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

lower extremity of the container reverse curl 2d. Thus, the central portion 4d of the patch top is displaced axially within the container and the peripheral annular portion 4e of the patch top is caused to conform with the inner circumferential surface of the curled end portion 2d of the container body member 2. The end of the container is then heated (for example, by conventional ultrasonic, induction or dielectric heating techniques) to effect bonding of the patch top member to the container and to the overcap member by the heat-responsive layers 4d and 4c, respectively.Thus, in the case where the second adhesive layer 4d comprises a layer of conventional hot melt material arranged at least on the peripheral annular portion of the patch top, the layer is softened by the application of heat to effect a bond between the patch top member and the container which is weaker than the bond between the patch top and the plastic overcap member. The shrink-fit tape 10 is then wound upon the container, and the container is passed through a separate oven to effect shrinking of the tape in tight engagement across the juncture between the lower edge of the flange portion 6c and the outer surface of the container body. The overcap member is thus connected against inadvertent displacement relative to the container.

Of course, various means may be provided for applying the first and second layers of adhesive. For example, the second layer of adhesive 4d could be coated on the inner circumferential surface of the reversely curled portion 2d prior to the mounting of the patch top 4 upon the open end of the container. Furthermore, it might be desirable to bond the patch top member 4 to the plastic overcap member 6 prior to the assembly of the plastic overcap 6 upon the curled end portion 2d of the container 2.

Finally, as shown in Figure 6, the central portions of the overcap and patch top members 6 and 4', respectively, may be flat and horizontal, the patch top member extending in contiguous engagement across the upper extremity of the reversely curled container end.

It will be appreciated from the foregoing that the invention provides closure means for closing the reversely curled end of a composite container, including a synthetic plastic overcap member which is removably connected with the container and is adapted to be reapplied to the container to reclose the end thereof. The patch top member is arranged between the container and the overcap member, the patch top member being bonded to the container by a weaker first adhesive material to define an hermetic seal, and to the overcap member by a stronger second adhesive, whereby upon removal of the ovrecap member, the bond of the first material is broken and the patch top member is moved simultaneously with the overcap member. Anti-tampering means, such as a shrink-fit tape, may be provided with either embodiment to reduce the possibility of inadvertent removal of the overcap member.

WHAT WE CLAIM IS:

1. A patch top container and closure assembly comprising a container body formed with an outwardly extending collar surrounding an opening at one end thereof and a closure for said opening comprising an impervious patch top member extending transversely across said one end of the container; a first adhesive layer hermetically but releasably bonding the patch top member with said one end of the container body, an overcap member extending transversely across said container with an inner surface of said overcap member contiguous with an outer surface of said patch top member, a second adhesive layer securing together said contiguous surfaces of said patch top member and said overcap member, said second adhesive layer producing a stronger bond between said patch top member and the overcap member than that produced by said first adhesive layer between said patch top member and the container body, and means releasably coupling said overcap member with said container, whereby when said overcap member is removed from the container the hermetically sealed bond between the patch top member and the container is automatically broken and access is afforded to the interior of the container, whereafter the overcap may be reapplied to sealingly close the container.

2. An assembly as claimed in claim 1, wherein the patch top member extends across and is in contiguous engagement with the margin of said one end of the container.

3. An assembly as claimed in claim 1 or 2, wherein said overcap member is formed of a thermoplastic synthetic plastics material.

4. An assembly as claimed in any one of the preceding claims wherein said overcap member is flexible and further includes a pull tab portion that extends downwardly from the overcap member adjacent the outer surface of the container body.

4. An assembly as claimed in any of the preceding claims wherein the surface of the overcap member remote from said one end of the container body is provided with a plurality of radially arranged strengthening ribs.

6. An assembly as claimed in any of the

preceding claims wherein the patch top member is flexible.

7. An assembly as claimed in any of the preceding claims wherein said patch top member consists of metal foil.

8. An assembly as claimed in any of the preceding claims wherein said patch top member is a substantially circular disc.

9. An assembly as claimed in any of claims 1 to 7 wherein said central portion of said overcap member has a flat horizontal inner surface opposite and extending transversely across said one end of the container body, the patch top member being generally planar and including an annular sealing portion opposed to and releasably hermetically bonded by a first adhesive means to said one end of the container body.

10. An assembly as claimed in any of the preceding claims, wherein the overcap member has a downwardly extending peripheral flange which extends concentrically about the container body and terminates in an inwardly directed locking shoulder which engages in snap-fit relation under the collar on the container body.

11. An assembly as claimed in claim 2 or in any of claims 3 to 8 as dependent on claim 2, wherein the overcap member has a central portion that projects axially partially within said one end of the container body to present a flat surface arranged transversely within said one end of the container body and contiguous with a central portion of said patch top member, which latter member also has an annular sealing portion releasably and hermetically bonded by said first adhesive layer to said one end of the container body.

12. An assembly as claimed in claim 11 wherein the central portion of the overcap member is surrounded by an annular recess which receives the collar at said one end of the container body, the annular sealing portion of the patch top member being maintained in conforming engagement with a rounded surface portion of the collar on the container body by a correspondingly rounded portion of the wall surface of the overcap annular recess.

13. An assembly as claimed in claims 10 and 12 wherein the co-operating rounded surfaces of the container body collar and the overcap member are arranged generally diametrically opposite the surface of said collar which is engaged by said annular locking shoulder, the locking shoulder being so arranged on the overcap flange portion that when it is in locking engage ment under the container body collar, the annular recess wall surface is biased in a direction to press the annular sealing portion of the patch top member into conforming engagement with the collar on the container body.

14. An assembly as claimed in any of the preceding claims and further including anti-tampering means connecting the overcap member and the body member for resisting the removal of the overcap member from the container.

15. An assembly as claimed in claim 14 wherein said anti-tampering means comprises a peelable strip of synthetic plastic material circumferentially arranged about and shrunk fit across the juncture between the extremity of the downwardly depending locking shoulder of the overcap member and the container body.

16. An assembly as claimed in claim 15 wherein said peelable strip extends completely about the outer surface of said locking shoulder and the adjacent marginal portion of the end surface of the overcap member remote from said one end of the container body.

17. A reusable closure for closing the open end of a container, comprising an impervious patch top member having thereon a first adhesive layer by means of which in use, the patch top member makes a releasable hermetic seal to the extremities of the walls of the container open end, said patch top member being bonded to the interior of an overcap member by means of a second adhesive layer producing a stronger bond between said patch top member and said overcap member than that produced by said first adhesive layer between said patch top member and said container walls, whereby when the overcap member is removed from the container the hermetic seal between the patch top member and the container walls is automatically broken, the overcap member having means thereon for maintaining it upon the container after said hermetic seal has been broken.

18. A method of closing the open end of a container having an outwardly extend ing collar at one end thereof which com prises the steps of arranging a patch top member upon the container end; bonding the patch top member to the container by means of a first adhesive layer, mounting upon said container and patch top member a removable overcap member, and bonding the inner surface of the overcap member to the patch top member, by means of a second adhesive layer, said second adhesive layer producing a stronger bond between said patch top member and the overcap member than that produced by said first adhesive layer between said patch top member and said overcap member, where by upon removal of the overcap member from the container, the releasable bond between the patch top member and the container is automatically broken.

19. A method as claimed in claim 18 wherein the overcap member is a synthetic plastics material and has an annular flange portion that extends concentrically about the open end portion of the container, and further including the step of shrink fitting a strip of shrinkable synthetic plastic material circumferentially about the container across the junction between the flange portion of the overcap member and the container.

20. A method as claimed in claim 19, wherein at least one of said first and second adhesive materials is heatresponsive, said patch top member being bonded by heat sealing to at least one of the container and overcap members.

21. A method as claimed in claim 20, wherein the overcap member has a central portion which extends slightly within the container to cause the central portion of the patch top member to be axially displaced inwardly from the extremity of the container end, said overcap member also having an annular curved intermediate portion which conforms with the inner surface of the reversely curled end portion of the container, thereby causing the annular portion of the patch top member contained between the intermediate portion and the container end to conform to, and to be in contiguous engagement with, the inner circumferential surface of the reversely curled container end portion.

22. A patch top container and closure assembly substantially as herein described with reference to the accompanying drawings.

23. A method of closing an open ended container substantially as herein described with reference to the accompanying drawings.