CA1291716C - Pack for filing materials capable of flow, having glass end walls - Google Patents

Abstract

ABSTRACT
Described is a pack for filling materials capable of flow, comprising side walls (1) which are connected together to form a tubular configuration by way of a longitudinal sealing seam, and end walls which are mounted to the ends of the tube and which form the bottom (2) and the top (5) of the pack. In that arrangement the side walls (1) comprise card which is coated with thermoplastic material and the bottom (2) of the pack comprises a separate, substantially flat wall portion and is sealed on the lower edge (3) of the tubular side walls (1). To provide a light, stable and inexpensive pack, the material of which is better utilisd in relation to the filling volume and can also be better re-processed, the invention provides that the bottom (2) and the top (5) comprise glass and are fluid-tightly welded to the tubular side walls (1) and that the top (5) has a closable pouring opening (10).

Description

lZ9~7~i Pack for filling materials capable of flow, having glass end walls The invention relates to a pack for filling materials capable of flow, comprising side walls which are joined together in a tubular configuration by way of at least one longitudinal sealing seam and end walls which are disposed at the ends of the tube and which for~ a bottom and a top of the pack, wherein the side walls comprise a carrier material, for example cardboard, which is coated on at least one side with thermoplastic material, and the bottcm of the pack is formed from a separate substantially flat wall portion and is sealed on to the lower edge of the tubular side walls.
Such and similar packs are known. In one case, the top of the known pack comprises thermoplastic material without a carrier or backing material, is injected on to the side walls along its outside edge, and has a pouring means.
Another pack is also known in which, although the side walls also comprise coated cardboard, the top and the bottom comprise thermoplastic material without a carrier or backing material. In the condition of readiness for filling, that known pack is of such a configuration that the top is injected on to the side walls along its four edges, whereas the bottom is injected on to the side walls only along one edge, for the purposes of filling the pack. The cross-section of that pack as well as the top and the bottom are substantially square or rectangular.
The bottom of the known pack as set forth in the opening part of this description is also quadrangular so that there is a certain reduction in volume in co~parison with the round top, so that the packing material is still not put to optimum use, in relation to the filling material to be contained in the pack. It has been found that all packs with plastics botto~s or tops suffer from the disadvantage that a certain level of gas permeability is inevitable so that easily perishable filling materials are put at 1~:9~7~6 risk when stored for a prolonged period of time. In particular cases sterilisation of the known packs has hitherto only been possible at a substantial level of cost. While the side walls are formed from flat webs of material which can be comparatively easily coated with gas-impermeable materials, for example metal foils, that procedure involves considerable difficulties, in relation to tops and bottoms.
Therefore, certain filling materials are transported in known glass bottles or flasks which however suffer from many known di~advantages, for example those involved in cleaning, closing and opening and the expenditure involved due to the weight thereof.
The man skilled in the ar~ must use a thick gauge for the walls of the glass containers so that the container which is used under rou~h conditions ln tran~portation, washlng and filling does not break. On the other hand glass ls a really ideal packaging agent, particularly if the aspect of environmental pollution is considered and consideration is given to the high recycling value, that is to say, re-usability. Nonetheless, for reasons of economy, a paper packaging means is frequently preferred to a glass bottle, when the enormous difference in weight and the transportation costs involved therewith are considered; and also the aspect of storing re-usable glass bottles. The weight of a durable 1 litre bottle is generally about 360 g.
The object of the present invention is therefore that of providing a light, stable and inexpenslve pack with the features of known packs as set forth in the opening part of this specification, the material of which however is better utilised in 1~917~6 2353~-70 relation to the filling volume and which is also better re-processable. The invention preferably also seeks to provide a gas-tight pack which can be satisfactorily sterilised and which remains aseptic over a prolonged period of time.
According to the invention, there is provided an aseptic pack for foods capable of flow, comprising side walls which are joined together in a tubular configuration by way of at least one longitudinal sealing seam and separate glass end walls which are welded to the side walls at the ends of the tube and which form a bottom and a top of the pack, said side walls comprising a cardboard carrier ma'erial, which is coated on the interior side with an oxygen-lmpermeable layer and being coated on at least one slde with thermopla tic material, said bottom having a substantially flat wall portion at the lower edge of the tubular ~ide walls, ~aid top having a closable pourlng opening, each of said end walls having a given thickness and a sealing surface extending axially of the pack for a length greater than said thickness and engaging the thermoplastic coatlng to provide a substantially gas-and-liquid-impermeable weld between the glass 2Q and the metal foil.
The invention offers an unusual combination of materials, namely paper and glass. Instead of the usual plastics materials for the top and the bottom, the invention uses glass which hitherto and ln part even nowadays the man skilled in the art considers to be non-weldable to plastics-coated paper It is known however for glass bottles also to be closed by thermopla~tic materials, instead of crown corks or the like. In that ~ituation, ~vl 1~91716 an adhesive or bonding agent was applied to the edge of the neck of lhe bottle, but improvements were considered to be urgently necessary, on the one hand because of the difficult process s~eps and on the other hand having regard to contamination of the foodstuffs in the bottles. Hot sealing adhesives were therefore discovered, which provide durable connections for example between glass and a plastics material. Therefore, even when dealing with fluid filling materials, it was accordingly in principle already possible to close bottles by a sealing action. It was hitherto not known however to provide a pack essentially comprising plastics-coated paper with a glass top or bottom. Although a paper sleeve or tuhe member has already been closed by means of aluminlum at the end~ thereof, it should be borne in mind in that connectlon that metals are deformable, 50 that the top~ and the bottom~ conslsting of metal can also be connected to the paper tube member by being flanged over and flrmly clamped ln place.
Such procedures cannot be used when employing glaæs instead of metal. In addition, the man skilled in the art always had to fear breakage of the glass top or bottom when a pressure was applied to the paper tube member.
The invention follows here a new path for providing a substantially lighter (lower weight) but nonetheless stable pack.
A tubular paper sleeve member which i5 open at the ends is produced in known manner from a web of paper which i8 coated with plastics material at least on one side. In a closing station, the topæ and ~ ,JI:`

1~91~6 bottoms which are kept in storage and which consist of glass are joined to the tube member, adjusted into position and welded. In that situation it is possible for example to use an induction welding apparatus. As the top has the pouring opening, the pack when produced in that way c~n be filled and subsequently closed.
It is particularly desirable if, in accordance with the invention, the glass is pressed glass. Such a material is to be considered as being 90% recycled glass. Environmental pollution caused by the packaging materials is therefore remarkably slight. It is immaterial in regard to production and function of the pack according to the invention if small stones, cords or other impurities are enclosed in the glass top whereby so-to-speak the quality of glass is lowered.
On the contrary, the top or the bottom (or both) can be inexpensively produced by means of simpler plants and the use of recycled glass by the manufacturers of liquid packs.
Although it has been found that, with a glass thickness of about 1.5 mm for the top and the bottom, the risk of breakage is negligible, even in the course of manufacture, and nonetheless the weight per top or bottom is for example in the region of 20 to 25 g, nonetheless, it may be particularly advantageous if the glass, in accordance with the invention, is prestressed. Such pre-stressing is known and is easy to achieve, there are many prestressed drinking glasses, motor vehicle glass is for example prestressed and so forth. In the polyliquid method, the tops and bottoms of glass are guided on a conveyor beltin a fluid, thereby providing prestressing and also hardening of the glass. A further advantage of the handling process is also a reduction in weight. m e pre-stressing effect however also gives a better level of strength so that it is also possible to use rougher production machines in which the paper tube members are pressed against the glass for sealing purposes, when producing the empty liquid pack.
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~?1917~6 The materials used for the tubular side walls, that is to say the sleeve or tube member, namely paper or card, coated at least on one side with plastics material, provide so-to-speak a soft suspension means for the two rigid glass discs or plates so that the pack can be not only satisfactorily processed but also filled, tra~sported and handled by the final consumer, without danger. The two glass plates are suspended on the tubular side walls in comparable manner to being suspended in a vibration-damping member. That unexpected combination of glass and paper therefore also imparts a high level of stability and strength to the novel pack.
It is advantageous in accordance with the invention for the glass to be coloured. Those glass colouring processes are also known per se. However, in combination with the opaque tubular side wall, that advantageously provides a high level of protection against light, from the ends of the pack.
In an advantageous further embodiment of the invention, the pouring opening in the top of the pack has an annular collar which extends outwardly in the axial direction of the pack and a sealing surface which lies in the axial direction is disposed at the outside periphery of the top and/or the bottom. The above-described configuration of the pouring opening not only provides a good way of filling the pack through the open pouring opening, but in addition closing thereof is considerably facilitated because the outwardly projecting annular collar on the pouring opening can be easily reached by a closing means. In that way the design configuration of the closing apparatus can be simplified and the process can be developed with a higher level of output. The fact that a sealing surface is provided at the outside periphery of the top and/or the bottcm improves the adhesion between the glass component and the paper tube. That sealing surface is substantially annular in the usual quarter litre, half litre, one litre and two litre packs, ~?~91~6 and will be from 1 to 7 mm and preferably from 2 to 5 mm in length.
The glass top or glass bottom of the filled or empty pack is thus prevented from coming loose from the paper side walls, or can come loose only when a certain amount of force is applied, when the pack is destroyed.
If, in a further advantageous embodiment of the invention, a bead and/or a sealing surface which is disposed transversely with respect to the axial direction is/are disposed at the outside end of the annular collar, that advantageously provides an increase in surface area at those locations to which other components, plates or discs have to be sealed in position, for example metal foils which are possibly coated, for closing off the pouring opening.
The bead may be easily formed as a cast bead when producing the glass top. It extends on the annular collar and consequently is of a shorter peripheral dimension than the above-mentioned sealing surface at~the outside periphery of the top or the bottonof the pack.
It is also advantageous in accordance with the invention for a closure cover comprising plastics material to be releasably mounted on the annular collar of the pouring opening. The closure cover serves primarily to provide for re-closability and may be made for example from polyethylene. After the pouring opening has been closed by the coated aluminiumfoil, the cover is pressed over the annular collar so that the aluminium foil is advantageously protected from blows or damage, during transportation of the pack. An inwardly projecting annular bead is preferably formed or moulded at the lower outside edge of the closure cover so that the closure cover can be snap-fitted on to the annular collar and has a self-holding function.
For opening purposes, the closure cover is removed, the metal foil is broken open and, after the contents of the liquid pack have been partly poured out, that is to say, the pack has been partly emptied, the closure cover can be snap-fitted into position again so that the 1;29~716 material remaining in the pack is protected from dust while there is also a certain degree of protection against the contents of the pack running out.
In accordance with the invention, the tubular side walls may also be internally coated with a metal foil. Aluminium is preferably again used for that purpose. In regard to aseptic milk packs, it is known per se for paper side walls to be covered with aluminium foil, so that the side walls are also made gas-tight. In regard to aseptic packs therefore, the known parallelipipedic packs which entirely comprise such coated paper have been frequently used. However, it would be desirable to go over to other kinds of pack, for reasons of consumption of material, sealing of the pack and problems involved in opening same. Particularly in relation to packs in which at least one of the ends is closed by a plastics top or bottom however, problems already arise due to gas entering the pack through the plastics material. If on the other hand, in accordance with the teaching of the present invention, glass is used instead of plastics material, those problems involved in making the pack gas-tight are overcome. The features according to the invention therefore also make it possible to produce a gas-tight and sterilisable pack. In the above-described production process, the sterilisation operation is carried out after the operation of producing the pack, that is to say after the glass plates or discs have been welded into the soft paper tube, that is to say, the tubular side walls consisting of plastics-coated card, and prior to the filling operation.
The ab~ve-indicated features may be used in accordance with the invention in a particularly advantageous manner when the cross-section of the tubular side walls as well as the top and the b~ttom are circular. Such a pack provides the optimum filling volume in relation to the pack material used, that is to say, it provides an l~t917~6 even better level of utilisation of material than in the case of a square bottom.
Refuse is nowadays already being collected separately and it would therefore also be possible to make the pack consisting of glass and paper in accordance with the invention re-processable with a srnall number of handling operations (cutting off the top and the bottom with a blade) because the separated materials and in particular the glass are very suitable for recycling. The novel liquid pack according to the invention provides a packaging means which is environmentally harrnless and which is advantageous in regard to transportation and which at the same time has a high degree of advertising effectiveness because printed advertising can be produced on the web of paper for making the tubular side walls in known manner.
By using different forrns of glass top and glass bottom, they can be made in such a configuration in thernselves that they can be highly advantageously stacked so that they can be delivered fran rnagazines to the finished paper tubes which are guided for example in a conveyor chain, in a practical and compact form.
Particular emkodiments thereof, further advantages, features and possible uses of the invention will be apparent from the following description of preferred embcdiments in connection with the accompanying drawings in which:
Figure 1 is a perspective view of a milk pack in accordance with a first embodiment of the invention, with the closure cover removed, Figure 2 is a sectional view through the pack shown in Figure 1 with a metal foil applied to the pouring opening, Figures 3, 4, 6 and 7 are broken-away and diagrammatic sectional views through the upper part of the tubular side walls with the top welded in position, in an open condition, 7~6 Figure 5 shows three open tops separately, in mutually superposed stacked relationship, Figure 8 shows a broken-away sectional view of another embodiment, with a metal foil being laid on the top, Figure 9 is a similar view to that shown in Figure 8 but showing a further modified embodiment of the top and with the closure cover shown separately in section thereabove, and Figure lO is a broken-away cross-sectional view through the tubular side walls with the longitudinal sealing seam and the edge protection means.
Figure l is a perspective view of the finished milk pack in the open condition. It comprises side walls l which are connected to form a tubular configuration by way of a longitudinal sealing seam 4 (see Figure lO), and end walls of glass, of which Figure l shcws only the top 5 while Figure 2 shows also the bottom 2. The side walls l comprise paper or card which is coated with thermo-plastic material on both sides and they are formed from a flat web which preferably has printing thereon. The web is formed into a tube and is closed to provide the tube configuration by means of the longitudinal sealing seam 4, in the manner shown in Figure lO.
A plastics strip 6 is sealed on the inside of the tube and extends longitudinally in the axial direction of the tube and forms the edge protection means so that fluid cannot penetrate into the free inner edge of the paper which is without plastics protection, and which could thus damage the paper.
Both the bottom 2 and the top 5 comprise a separate, generally flat wall portion which is of a disc-like configuration in the case of the round embodiment and of a plate-like configuration in the case of other embodiments. The bottom 2 is sealed to the lower edge 3 of the side walls l. The annular sealing surface 7 is disposed on the inside of the tubular side wall l, at the bottom at the edge 3 thereof on the one hand, and at the outside periphery of the '1?~9'1.7~fi bottom 2 on the other hand. So that the above-mentioned sealing surface which extends in the direction of the axis 8 of the pack is of a given height or length of for example from 1 to 7 mm, preferably 2 to 5 mm, a groove or channel is formed in the bottom 2, out of the plane which is disposed transversely with respect to the axis 8.
That groove-like channel 9 simultaneously imparts an additional stiffening action to the bottom 2.
The bottom 2 and the top 5- comprise glass which is preferably coloured for the pu~poses of protection from light and which is preferably prestressed pressed glass.
The top 5 could also have such a V-shap~d or trapezoidal annular groove 9, like the bottom 2, but such a construction is not shown in the drawings. On the contrary, the top 5 is stiffened by other annular edges or the pouring opening which is generally identified by 10. The pouring opening 10 is disposed centrally in the circular top 5 and is formed by an annular collar 11 which projects upwardly and outwardly in the direction of the axis 8 and which at its top, at its outermost end, has a bead 12 (see Figure 7) or a sealing surface 13 which is disposed transversely with respect to the axial direction 8. It is also possible to inter-pret the bead 12 in Figure 7 in such a way that it forms such a sealing surface as is denoted by reference numeral 13 in the other embodiments.
Upwardly and outwardly, the pouring opening is closed by an aluminium foil 14 which is coated on both sides with thermoplastic material. The aluminium foil 14 is shown only in Figures 2, 8 and 9.
In Figure 2, the aluminium foil 14 is shown as being bent downwardly on the outside at the periphery of the annular collar 11.
That is effected by means of the closure cover 15 of polyethylene, which had been releasably mounted on the annular collar 11 by ~l9l7~6 the closure cover having been snap-fitted over the inwardly projecting annular bead 16 shown in Figure 9 on to the annular collar 11 and over its bead 12 or the annular outside edge of the sealing surface 13~
Figure 9 shcws for example the condition in which the aluminiurn foil 14 is still lying flat on the sealing surface 13, namely before the closure cover 15 has been snap-fitted on to the annular collar 11 and engaged in position thereon. When thereafter the closure cover 15 is removed, that gives the configuration shown in Figure 2.
It will be appreciated that, for pouring out material from the pack, the aluminiurn foil 14 is broken open and, if the pack has been only partially emptied, the closure cover 15 can be used fr re-closing the pack.
Figure 3 shows a first err~odiment of the cross-section of the top 5, which is also to be seen fr~n the views shown in Figures 1 and 2. Shc~n herein is the sealing surface 13 which is disposed perpendicularly or transversely with respect to the axis of the pack, with its outside edge 17 over which the internal bead 16 on the closure cover 15 can engage. In a dcwnward direction, the annular collar 11 gc,es frc,m the cylindrical configuration into a frusto-conical configuration in order then in the lcwermost region to go into a plane, thus forming an annular surface 18 which is to be found in substantially all tops 5, except in the em~odiment shown in Figure 8. Formed at the outside periphery of the top 5 is the sealing surface 19 which is disposed in the direction of the axis 8 and which is annular and which is of a height or length of about 1 to 7 mm and preferably 2 to 5 mrn, in the direction of the axis 8. That provides good adhesion between the glass top 5 and the paper wall 1.
In the embodiments shcwn in Figures 4, 7, 8 and 9, there is also an annular surface 20 which covers over the edge of the paper and which lies beside the sealing surfacel9 and outside same.

i?.9~7~6 There too there is a welded join between glass and paper. Liquid can therefore not penetrate into the open edge of the paper side wall 1.
Figure 5 shows the good stackability of the top 5 in accordance with the second embodiment as shown in Figure 4. Other tops are also stackable in a similar manner.

Claims (13)

1. An aseptic pack for foods capable of flow, comprising side walls which are joined together in a tubular configuration by way of at least one longitudinal sealing seam and separate glass end walls which are welded to the side walls at the ends of the tube and which form a bottom and a top of the pack, said side walls comprising a cardboard carrier material, which is coated on the interior side with an oxygen-impermeable layer and being coated on at least one side with thermoplastic material, said bottom having a substantially flat wall portion at the lower edge of the tubular side walls, said top having a closable pouring opening, each of said end walls having a given thickness and a sealing surface extending axially of the pack for a length greater than said thickness and engaging the thermoplastic coating to provide a substantially gas-and-liquid-impermeable weld between the glass and the metal foil.

2. An aseptic pack as set forth in claim 1 characterised in that the glass is pressed glass.

3. An aseptic pack as set forth in claim 1 characterised in that the glass is prestressed.

4. An aseptic pack as set forth in claim 1, 2 or 3, characterised in that the glass is coloured.

5. An aseptic pack as set forth in claim 1 characterised in that the pouring opening in the top has an annular collar which extends outwardly in the axial direction of the pack and that said sealing surfaces are disposed at the outside periphery of the top and the bottom whereby said top and bottom fit within the tubular side walls.

6. An aseptic pack as set forth in claim 5 characterised in that at least one of a bead and a sealing surface is disposed transversely with respect to the axial direction of the pack at the outer end of the annular collar.

7. An aseptic pack as set forth in claim 1 characterised in that the pouring opening is closed by a metal foil.

8. An aseptic pack as set forth in claim 1, wherein said top has an annular collar extending axially outward and terminating in said pourable opening, said packs including a closure cover comprising plastic material releasably mounted on the annular collar of the pouring opening.

9. An aseptic pack as set forth in claim 1 characterised in that the cross-section of the tubular side walls and the outlines of the top and the bottom are circular.

10. An aseptic pack according to claim 7 wherein said foil is coated with thermoplastic material and is sealed to said collar surrounding said opening.

11. An aseptic pack according to claim 8 wherein said collar terminates in a peripheral bead, said closure cover having a lip engaging under said bead.

12. An aseptic pack according to claim 11 including a thermoplastic-coated metal foil disposed between said collar and said cover, said foil being wrapped around said bead.

13. An aseptic pack as set forth in any one of claims 1 to 12 wherein said oxygen impermeable layer comprises a metal foil.