IE43547B1 - A can-like container - Google Patents

Description

The present invention relates to containers and to a method of manufacturing containers.

According to the present invention there is provided a container having a wall comprising a tearable lining and a substantially rigid outer protective plastics layer overlying the lining, said plastics layer being an injection moulded layer and having one or more first lines of weakness (as hereinafter defined) formed during moulding and defining an openable portion therein and one or more second lines of weakness defining a raisable tongue for gripping and opening said portion, which first and second lines cooperate to define a lining-piercing portion of the plastic layer which pierces the lining when the tongue is raised, and said plastics layer being attached to the lining in such manner that the tongue can be raised from the lining but the lining is torn open by movement with the openable portion of the lining portion underlying said portion. The term lines of weakness as used in this Specification (including the claims thereof) means a line of reduced strength and includes slits extending through the plastic layer.

Xn some preferred arrangements the tongue is not attached to the underlying portion of the lining but the openable portion (except for any tongue portion enclosed 435 4 7 therein) is attached to the underlying lining over substantially all of their opposed surfaces.

Conveniently the tongue may be located completely within the openable portions. Also conveniently the tongue and the lining-piercing portion of the plastics layer may be thicker than the surrounding portions of said layer. Xn some arrangements the tongue may have a projection adapted to ba engaged by a nail of the person opening the container.

The said lines of weakness in the said outer protective plastics layer may comprise grooves in the outer surface of the plastics layer, and in a preferred arrangement the groove or grooves constituting the first lines of weakness may extend through the plastics layer over at least the greater part of their length.

In some preferred forms of containers embodying the invention the said lining of the container is gas-tight, and conveniently the gas-tight layer may comprise a laminate of aluminium foil sandwiched between two plastics layers. In such a case, the said plastics layers of the laminate may conveniently be formed of oriented polypropylene. In such an arrangement, the aluminium foil of the laminate is preferably 8 to 20 microns thick, most preferably about 12 microns thick, and each of the oriented polypropylene layers of said laminate is preferably 18 to 35 microns thick, most preferably 20 to 25 microns thick.

Conveniently a container according to the invention may have the said outer plastics layer thereof formed of polypropylene.

In some preferred arrangements of a container according to the invention, the container may comprise a tubular body closed at one end by said wall. In such a case the tubular body may conveniently comprise an internal seamless, preferably extruded, plastics sleeve, an intermediate gas-tight layer and a protective outer - 4 plastics layer.

In a convenient arrangement of a container according to the invention the plastics layer externally bounding the openable portion in the region of the lining-piercing portion may be reinforced to facilitate piercing of the lining on raising the tongue.

Further conveniently in containers according to the invention the lining-piercing portion may be located at a comer of the wall.

There is also provided in accordance with the present invention a method of manufacturing a container embodying the invention as set out above, the method comprising treating the area of the lining to underlie the tongue to prevent adhesion of plastics material and moulding directly on to the lining the plastics layer with the lines of weakness being formed during moulding.

In such a method the said treatment of the area of the lining underlying the tongue conveniently comprises lacquering said area.

There is further provided in accordance with the invention a container whenever manufactured by a method as set out in the preceding paragraphs.

Embodiments of the invention in the form of a container and a method of manufacturing such a container will now be described by way of example with reference to the accompanying drawings in which:Figure 1 schematically shows a container embodying the invention in the form of a finished can-like package with an indicated opening device? Figures 2a and 2b are two sections perpendicular to each other through a body intended to be used for the manufacture of the middle part of the package according to Figure 1? 354 7 - 5 Figure 3 is a section through a portion of a wall of the middle part of the package according to Figure 1; Figure 4a shows a bottom part of the package according to Figure 1 before the mounting thereof; Figure 4b illustrates a method of manufacturing the bottom part according to Figure 4a; Figure 5 shows the bottom part attached to the can-like package according to Figure 1, i.e. a section on line V - V through the lower portion of Figure 1; Figure 6 is a section through an opening device which is more closely shown in Figure 7 together with the rest of the package, as seen from the above, the embodiment shown in Figures 6 & 7 being somewhat modified as compared with Figure 1 and illustrating particularly the container and method of construction embodying the invention.

Figure 8 schematically shows a plant for the manufacture of packages according to Figures 1-7; Figure 9 shows how a round, extruded plastic tube is reshaped into a rectangular cross-section form, although it will be appreciated that other cross-section forms are possible; Figure 10 schematically illustrates a method to line the body according to Figures 2a and 2b with a foil of aluminium or similar substantially gas-tight material; Figures 11a - 11c more closely illustrate said lining operation; Figure 12 shows the hardening of the lined body parts in an oven prior to the cross-cutting as shown in Figure 11c; and Figure 13 illustrates the reshaping of the body parts before they are provided with caps and bottoms, - 6 respectively, although it will be appreciated that such a reshaping is not always required.

The package shown in Figure 1 by way of example constitutes a container forming an embodiment of the invention, and consists of a case-like middle part 1, a cap 2 and a bottom part 3 attached thereto, the cap part being provided with an opening device.

As best shown in Figures 2a, 2b and 3, the middle part 1 is made up of an inner body la forming an inwardly unbroken plastic layer, an intermediate layer lb of aluminium foil or a corresponding substantially gas-tight material, and an outer plastic layer lc protecting said intermediate layer lb. The intermediate layer of aluminium on each side may be enclosed with glue layers Id and le, respectively. The adhesion, however, also may be effected in another way, for instance by means of inductive welding.

The bottom part 3 is more closely shown in Figures 4a and 4b, of which the latter figure illustrates the method to manufacture the bottom part. This bottom part consists of an outer plastic layer 3a which is thermoformed or formed in another way, for instance injection moulded with a portion 3b extending into the middle part 1 and a frame portion 3c surrounding the bottom edge If of the middle part. On the inside the bottom part is provided with a layer 3d of aluminium foil or a corresponding substantially gas-tight material which therefore is protected by the outer plastic layer 3a.

The layer 3d may be attached to the layer 3a as shown in Figure 4b. The layer 3a is arranged on a mandrel 5 provided with an inner inductor 6 for inductive welding.

On the top of the portion 3a is placed the foil 3d which may be supplied in the form of a continuous web which is punched by means of the schematically shown punch 7.

After the punching the foil 3d is depressed into the - 7 frame portion 3c by means of a forming tool 8. If necessary, said tool may be cooled in order to cool the weld effected by means of the inductor. Suitably the welding here is effected in such a way that the greater part of the foil 3d is attached to the layer 3a, whereas, however, a margin area 3d' is left free. In practice it has proved suitable for the layer 3d to use a laminate of aluminium foil between two outer layers 3d'' of polypropylene.

In Figure 5 the bottom part 3 is attached to the middle part 1. Also this attachment operation suitably may be executed by means of inductive welding in substantially the same way as the welding of the inner foil 3d according to Figure 4b. Simultaneously a certain graduation may take place in the end portion, as appears from Figure 5, in order to avoid too far projecting portions.

Figures 6 and 7 more closely and somewhat modified show the opening device indicated in Figure 1 with reference numeral 4. The opening device consists of two tearing grooves 4a and 4b, respectively, of which the tearing groove 4a defines the produced opening whereas 4b defines a grip tongue which in the example is completely located within the tearing groove 4a. Reference numeral 4c is a hatched area in Figure 7 which indicates a lacquering between an outer suitably injection moulded top portion 9 forming an outer layer and provided with the above tearing grooves 4a and 4b, and an inner layer 10 having a desired tightness. By this means the grip tongue 4d formed by the tearing groove 4b may be easily gripped. This is further facilitated in that said grip tongue 4d is made thicker and provided with a nail ridge or gripping edge 11. The grip tongue 4d runs into a prong 4e which likewise is formed with said thicker material. By this means said prong easily can pierce the - 8 plastic layer 9 when the grip tongue is forced upwardly from the position shown in Figures 6 and 7. This piercing is further facilitated when the material around the prong 4e is stiffened, for instance by means of an injection moulded stacking flange 12 or simply by means of its location in proximity to the corner portion 13 stiffened as well by the top part 2 as by the middle part 1. The tearing grooves 4a and 4b either may extend to the inner gas-tight layer 10 or be made somewhat shallower. In both cases it may be suitable to interrupt the outer tearing groove 4a at one or more places 4a' in order to facilitate the flow of the injection moulded material. In Figure 6 reference numeral 2a is a portion extending into the middle part 1 and being surrounded by a frame portion 2b enclosing the top edge of a middle part 1.

Figure 8 schematically shows a plant for the manufacture of a package described above. Since many particulars of this plant either are known per se or obvious to a professional man the plant is partially shown in the form of a block diagram. In this figure, 14 is an extruder for the extruding of a round tube la' of plastic, for instance polypropylene, polyethylene or the like. The tube then moves through a graduation apparatus which is more closely shown in Figure 9 and in which the tube is reshaped into a square cross-section profile The tube now has the reference numeral la11. The drawing through the graduation apparatus 15 is made by means of a drawing apparatus 16 and is finished in a cross-cutting machine 17 in which body parts la''' are produced. Said body parts la11' correspond to two or more of the body parts la shown in Figures 2a and 2b.

The body parts are advanced to a sheet feeder apparatus 19 which is supplied with sheets from a glue application unit 18. In said unit 18 a web-shaped material, such 3 3 4 7 - 9 as a laminate of, for instance, aluminium and polypropylene, is provided with a glue which is partly dried. The material then is cross-cut into suitable sheets which are rolled on to the body units la111 as is more closely shown in Figures, lla and lib. The glue application proper is best shown in Figure 10. In this way lengths 1' are produced corresponding to two or more middle parts 1 according to Figure 1. Said lengths 1' are transported into a curing apparatus 20 which is more closely shown in Figure 12. Then they are further transported into a finish cutting apparatus 21 in which they are cross-cut into middle parts 1 which are transported into a cap manufacture and welding apparatus 22. The middle parts 1 with caps 2 mounted thereon are then transported to a bottom application apparatus 23 which bottoms are supplied from a bottom manufacture plant 24, for instance a vacuum forming machine. Said bottoms are here loosely mounted after which the ready packages are transported into a packaging unit 25 from which the packages are transported to filling at which the loose bottoms are temporarily removed during the filling after which they are definitely welded on to the packages. By means of this proceeding very high hygiene can be maintained.

As mentioned above, Figure 9 shows the graduation unit 15 in which the extruded tube la' is reshaped into a tube la1' having a rectangular cross section form. This is made by means of closely mounted discs 26 between which all along is percolating a certain quantity of water for lubrication and cooling purposes and which are enclosed in a chamber 27 in which the water is at a lower pressure than the pressure in the tube in order to facilitate the forming of the tube la'. At the rear end of the chamber 27 is closed fay a sleeve sealing 28. Outside the sealing there are further cooling water spreaders 29. This reshaping of a thin material is supposed per se to ‘17 - ίο involve an important novelty. With a thin material in this case is meant a material having a thickness of about 1 mm or less.

Figure 10 shows the glue application unit 18. In this unit a laminate 31 is removed from a roll 30 and through the glue application means 32 proper conveyed into a drying oven 33 via various pulleys (without reference numerals), and to a sheet cross-cutting unit 34 having a knife 35 and a feeding chain 36. The chain for instance may be provided with grippers for feeding the cross-cut sheets 37 (see Figure 8). The sheets by means of a pressing roller 39 are applied to the body units la'1' which are threaded on the mandrel 40. Before the sheets 37 are brought into contact with the units la'11 the latter are treated by means of a schematically shown treating plant 41. This plant preferably consists of a so-called corona-apparatus but the treating also may be made in other ways, such as by means of a free flame. By this an oxidation of the surface takes place through which the adhesion of the sheets is facilitated.

Figures 11a through lie schematically illustrate how the label or sheet 37 is applied to the body unit la''1 which then is cross-cut by means of the cutting knives 42. Prior to this cutting the body units la'ww, however, preferably are conveyed through the curing oven 20 shown in Figure 12. Such an intermediate curing has proved to facilitate the cutting in the following crosscutting station 21, in that the hardening reduces the risk of delaminating during the cutting operation.

The invention of course is not limited merely to the embodiments described above but may be varied within the scope of the following patent claims. Thus, for instance, the thickness of the various material layers may be varied within wide limits without departing from the scope of the invention. In preferred practice, how4354? - 11 ever, It has proved appropriate to use for the inner extruded casing a polypropylene material having a wall thickness less than 1 mm and preferably in the range 0.4 and 0.8 mm. Particularly good results have been obtained with a thickness of about 0.5 mm. On the outside this inner casing preferably is provided with a laminate material consisting of aluminium and polypropylene. Here practical experimental works have proved that the aluminium layer should be between 8 and 20 microns, preferably 12 microns, and the outer polypropylene layer between 20 microns and about 60 microns, preferably about 50 microns. Correspondingly, practical experimental tests have proved preferably for the inner layer 3d of the bottoms to use a laminate of an aluminium foil in the range 8 and 20 microns, preferably 12 microns, between two polypropylene layers of about 50 microns. As an inner layer in the cap there is used a laminate of an aluminium foil between two films of oriented polypropylene. Here the same values as mentioned above may conveniently be used for the aluminium foil, for the films of oriented polypropylene a thickness of 18-35 microns, preferably 20-25 microns, may be used. Also the form and construction of the particulars of course may be varied. As shown in Figure 13, the caselike middle part can be reshaped before securing the cap and bottom part thereto.

In Patent Specification Ho. 43546 we have claimed a container comprising an openended tubular body comprised of an internal seamless plastics sleeve, an intermediate gas-tight layer and a protective outer plastics layer, and closed at its respective ends by top and bottom walls, each of said walls being comprised of a gas-tight layer and a protective outer plastics layer.

Claims (22)

1. CLAIM Si1. A container having a wall comprising a tearable lining and a substantially rigid outer protective plastics layer overlying the lining, said plastics layer being an injection moulded layer anti having one or more first lines of weakness (as hereinbefore defined) formed during moulding and defining an openable portion therein and one or more second lines of weakness defining a raisable tongue for gripping and opening said portion, which first and second” lines cooperate to define a lining-piercing portion of the plastics layer which pierces the lining when the tongue is raised, and said plastics layer being attached to the lining in such manner that the tongue can be raised from the lining but the lining is torn open by movement with the openable portion of the lining portion underlying said portion.

2. A container as claimed in Claim 1 wherein the tongue is not attached to the underlying portion of the lining but the openable portion (except for any tongue portion enclosed therein) is attached to the underlying lining over substantially all of their opposed surfaces.

3. A container as claimed in either of the preceding Claims wherein the tongue is located completely within the openable portion.

4. A container as claimed in any one of the preceding Claims wherein the tongue and the liningpiercing portion of the plastics layer are thicker than the surrounding portions of said layer.

5. A container as claimed in any one of the preceding Claims wherein the tongue has a projection adapted to be engaged by a nail of the person opening the container. 4 3 3 4 7 - 13

6. A container as claimed in any one of the preceding Claims wherein the lines of weakness are grooves in the outer surface of the plastics layer.

7. A container as claimed in Claim 6 wherein the groove or grooves constituting the first lines of weakness extend through the plastics layer over at least the greater part of their length.

8. A container as claimed in any one of tha preceding Claims wherein the lining is gas-tight.

9. A container as claimed in Claim 8 wherein the gas-tight layer comprises a laminate of aluminium foil sandwiched between two plastics layers.

10. A container as claimed in Claim 9 wherein the said plastics layers of the laminate are formed of oriented polypropylene.

11. A container as claimed in Claim 10 wherein the aluminium foil of the laminate is 8 to 20 microns thick and each of the oriented polypropylene layers of said laminate is 18 to 35 microns thick.

12. A container as claimed in Claim 11 wherein the aluminium foil of the laminate is about 12 microns thick.

13. A container as claimed in Claim 11 or Claim 12 wherein each of the oriented polypropylene layers is 20 to 25 microns thick.

14. A container as claimed in any one of the preceding Claims wherein the outer plastics layer is formed of polypropylene.

15. A container as claimed in any one of the preceding Claims wherein the container comprises a tubular body closed at one end by said wall. 43S47

16. A container as claimed in Claim 15 wherein the tubular body comprises an internal extruded plastics sleeve, an intermediate gas-tight layer and a protective outer plastics layer. 5

17. A container as claimed in any one of the preceding Claims wherein the plastics layer externally bounding the openable portion in the region of the liningpiercing portion is reinforced to facilitate piercing of the lining on raising the tongue. 10

18. A container as claimed in any one of the preceding Claims wherein the lining-piercing portion is located at a corner of the wall.

19. A container as claimed in Claim 1 substantially as hereinbefore described with reference to and as 15 shown in Figures 6 and 7.

20. A method of manufacturing a container as claimed in Claim 1 which comprises treating the area of the lining to underlie the tongue to prevent adhesion of plastics material and moulding directly on to the lining 20 the plastics layer with the lines of weakening being formed during moulding.

21. A method as claimed in Claim 20 wherein said treatment of the area of the lining underlying the tongue comprises lacquering said area.

22. 25 22. A container whenever manufactured by a method as claimed in Claim 20 or Claim 21.