AP3A

AP3A - A packaging container and a blank for the manufacture of the same.

Info

Publication number: AP3A
Application number: APAP/P/1984/000004A
Authority: AP
Inventors: Rolf Ignell
Original assignee: Ab Tetra Pak
Priority date: 1983-09-16
Filing date: 1984-09-14
Publication date: 1987-04-16
Also published as: ZA84694B; SE8304987D0; GB2146624A; SE436640B; ZW5884A1; BR8404511A; GB8422937D0; AP8400004A0; KE3815A; GB2146624B

Abstract

Packing container of the non-returnable type are used, among other things, for the packaging of fermenting beverages. The carbon-dioxide formed in the fermentation must be allowed to leave the package, since otherwise the latter will burst owing to the internal pressure. A packing container and a blank for the manufacture of the same which make possible a ventilation of the container without the foam formed in the fermentation being entrained and ending up outside the package is provided with a pressure-equalizing opening arranged between a number of material layers forming the upper part of the packing container, which are sealed together for the purpose of closing the packing container but are partly non-sealed so as to form the said pressure-equalizing opening, and an antifoaming agent located in the packing container. The antifoaming agent preferably has surface tension reducing properties and may be polyvinylaloohol with 88% degree of hydrolysis.

Description

BAD ORIGINAL ft

t. Η 3 a packi»:; co*.·: *»:’.·?> a''> a n.·.?.'.·' fop. tie j v.· •T)p r..' -·, :: Γ,νι·:

nt

The p» ? b'..‘7.k f'r the :: 5 the ;:or-r'-..urr.a-l r? 2 ores ?i . k irg 'r a: J : Ά -:. -·?. f- cunt 'i:.· ;s c f ; ··-»<. ; o_ p'.-.u.t £jr _i:e -g cf :f Lie i id i .idc.iurfs, e.g. raj Ik , beer, exile oil and others. Eich tyre cf cf.tK.vi' presents trie package rah v‘actor er Kith sf-ciai prcblerc. !k,wvfr, these problens are col zed cne after the other ano the number of products 10 which car. be cache3 increases continuously. Certain types of tcr.it.' ts, though, have properties which die particularly difficult to control. Such a material is Sorchx·: b.er, a traditional alcoholic drink v.'hich is produced and drunk i.r. particular m Southern Africa. This bweragu, which his nc s imilarity with 15 e.g. European beer, is packed and distributed whilst it continues strongly to ferment which means that the packing containers which are v ed must have some form of pressure equalizing opening, since otherwise the carbon dioxide liberated durug the fermenting process (approx. 17 litres carbon dioxide are formed during the 20 fermentation cf 1 litre beer) causes the package to start leaking and ever, to burst.

A solution of this problem inned.’ ately coming to mind is to rrv _ tr.e upp-er, not liquid-filled- Cutt of the packi: ; container with a hole penetrating the package wail. Through this hole the carbon dioxide formed can esca-e. however, it is found in practice that the beer foams so strongly dur’.-.g the fcrmentation that the upper part cf the packing container is filled with feat which, because of the pressure in the packing container, is entrained by the escaping carbon dioxide tr.rough the hole and emanates ir. the form of foam or liquid alcr,g the outside of the package. This of course is undesirable, especially if the beer foam contains a large amount of powder and yeast particles which attach themselves to, ar.d form a sticky coating on, the outside of the packing container. During the transport of a number of packing containers in a col35 lective holder the beer foam emanating acts as a glue which binds together the walls of the individual packing containers so that

BAD ORIGINAL ft they car. anly co separated from one a.noth?.·· uJih difficulties.

In	attempts to diminish '	•;r.G	foam pre'.. 1-,m in the	t1~ronentroned
type of	packing ccnfair.ee it 1 c ten it -3		be^n f r ·. ^r ·., to place	cn the one
hand pre	il isir.o/ as 1	* “ j	n as nos.. .Li? in the	packing cm-
5 tainer,	and on toe other f. md	to	ruisc the height of	f'.-o packing

container for a given volume of contents above what it is customary for less problematical, non-foaming contents. This of course entails an appreciably greater consumption of material which is a considerable disadvantage. In practice the method has not been effective either, since under certain conditions, e.g. at the transport over uneven, poorly surfaced roads in not climates the fear, .and gas formation becomes very violent and overfills ever, a very large so-called headspace in the upper part cf the package.

In spite of a number of trials no packing container of the non-returnable type has been presented up to now which is suitable for the packaging of Sorghum beer. Such a packing container on the one hand has tc meet the conventional demands which are made cn rn^st types of packing containers for liquid contents, and on the other hand make possible the packaging of Sorghum beer in such a manner that the continuing fermentation and discharge of carbon dioxide is r.ot. prevented. Only in this manner is it possible to ensure that the contents as well as the packing container are in fir cluss condition when they reach the consumer.

It is an object of the present invention to provide a packing container fcr gas-generating contents which is not subject to the disadvantages of previously known similar packing containers.

It is a further object of the present invention to provide a packing container which is intended in particular to make possible the packaging cf fermenting and foaming contents and which cakes possible a continuous pressure-equal icing between the interior of the packing container and the environment without foam from the contents leaking out or foreign, external objects being able to enter into the packing container.

It is a further object cf the present invention to provide a packing container which is optimally adapted ^ho the packaging of Sorghum beer and which can be manufactured and distributed at low

AP 0 0 0 0 0 3

BAD ORIGINAL ft

Λ :^Λ

J coat.

7res' ft :cr c h - < . - _;. . « ;·,<·»: i :· vr j \r. a ' :.: ~s.~ the i...verti;n in 7:. at pv-vir - c r . ir.o:^v h : · tee:; g.v. r, eno cha r?.c * -r i : t i: %·:’ ’ i ' .-.-.1 ::: w.ti. a ..rccture-cjc .17.:1-,7 opening :rrjn_t;>:.: b?twe;:. ·. r. ameer -r..,L:r.^l layer ·<.·;

upper ps;'7 tr_- r : >'Zu , ri.ru.:r u .a: ,re ^! ai . . t· :· -,.·>· the purpose of ci'.^nf ' : a .'jcu.’s.g --.-, t liner ou‘ ir·. --rtly netsealed so a3 to for:’: the ^r'ressar a-cqu.alis: ng :ttnr -.

Preferred ;.nh: -is of the p--ckcontains- in accordance '3 with toe: invention '.3»e 1-.(-, giver,, moreover, the < r?.r aeterist xct which are evicant from o ts iciiary c.'ciai; 2 to 'rj inclusive.

It is c further criect of the pro*cr.t invention is provide a blank for the manufacture of the said packing container and the invention t-.erefore also relates to a blank for the manufacture of packing containers, this blanx being given the characteristic th_ it has a costing of onti.foaming agent which substantially covers tne surfaces of the backfolding panels facing towards the interior of the packing container.

BAD ORIGINAL fi

Pref-rmed e~h invention nave η· e evident font subsi

By provedint in accordance with arrangement as wel located in r’litre which the internal cf gas without any roam from tire cask

'.:._‘;.ntj or the blank in accordance with tire r. g -v n. moreover. the characteristics which are diary claim 15 to 18 incl usive.

the pocking cent sneer and the blank for the same tire invention wrtn a rress’rre-ecaalizing vent I as a layer of antifoe.aing agent appropriately r thereto, a parking container is obtained in excess pressure can ba squalired by discharge contents emanating in the form of liquid or i.tg container. In the preferred embodiment cf the packing container this in prevented, noreever, by the gradually narrowing channel which connects the contones space of the packing container with the pressure-equalizing opening. This arrangement also ensures that ar.v leakace of the contents is reduced £ 0 0 0 0 0 dV even if the packing container tilts over.

I is obvious that the tacking container ar.d the blank in accordance with the invention can be designed within the scope of the concept of the invention and the following claims in a number of different ways. The pressure-equalizing openings as well as the antifeaming agent may be used in packing containers of varying geometrical design, but a particularly appropriate packing c* ,-r has proved to be the type known in itself which is called cable-top package or 'ridge package.

A preferred embedirent or the packing container and the blaree in accordance wash the invention will r.ow be described in more detail wit; special reference to the attic..ed diagrammatic crawirga which, shews the invention sc embodied in a gable-top package.

Fig.l shews in perspective a packing container in accorc-ance with the Inver.cron.

Fig. 2 shews fret; tha race the upper part of the packing container in accordance with. fig. 1, certain parts having been cut away to facilitate understanding of the invention.

Fig.3 shows the upper part cf a oa~king container blank in accordance with the invention.

The preferred embodiment of a packing container I in accordlance with the invention shown in fig.l is car.ufsecured from

BAD ORIGINAL

>·*· a : mar. t. m Ly rec .sr„·u .ar blar.- or .aninaed pat ·. inc material. The rummy xct-rial it :1:/..1 le h m rclitively str -Ξ ard ;omrrmm c ·.·.-. era! - <'* ' z>: clbctus usually n.i;er wnich .3 ccverud on mfh-r 3:.it w^’dn thin, 1 iqrid-tight layers of h’.craoj I no-i c natur.· a. , ym.m.mbly poly char.·:.. Beside anting as a stopping lay?¹.· .'hie.: : rcvt-r.ts any leaking oat of the liquid contents from the packing . ontai.-.er, the· thermoplastics also serves as a sealing material w-.er. the packing material blank 2 is converted to a packing cents.ner 1, by folding and sealing.

The embodiment et the packing container shown, preferred in this context, is of th. ’'yule-top type md thu.· comprises a substantially paraLielecip.edic main body which is provided with a ridgeiike top. The greeter cart ci the L.ain body 01 the packing container is foiled with. liquid contents, whilst the ridyelike top forr.s a free space or so-called headspace above the surface of the contents. This main type of packing coiituiner has been well-known -ur a long time and there io nc> need, therefore, to describe here more closely either the detailed construction of the packing container or the manner of manufacturing and shaping of the sane.

The main body of the packing container is constituted, however, of four substantially rectangular side wall panels 3 which are sapor.-_nd from each other by (ceans of vertical crease lines 4.

____. base of the packing container, similar to the top, is obtained by fold, ng and sealing -f a rv.ucber of natcrial panels designed in a suetc.-ie manner.

The tor) part located at the upper or.d of the rale wall panels too comprises 1 nurher of wall panels separated by means of crease line.-. More particularly, each of the two opposing side wall panels 3 of the main body «manges over at its toe into rectangular main paneis 5 which by moans of a horizontal creme lino 6 are separated from the main body of the packing container. The rectangular panels 3 have a width corresponding to the width of the side wall panels 3 and are limited in lateral direction by crease lines 7 which constitute a continuation of the vertical crease lines 4 between the side wall panels 3. Each of the two remaining opposing side walls 3 of the main body changes over at

BAD ORIGINAL

J its top into panels corresponding in : i:e -and shape to panels 5, each of whin hcve'/sr being divided into three triangular panels. One of these triangular panels, called infolding panel, is indicated by reference nur.berti 3 and is substc.r.tially isosceles.

The triangular infolding panel 3 is terminated at its lower end by the crease line 6 mentioned earlier which extends over the whole wiith of the container blank and which constitutes the base edge of the triangle as well as the upper limitation edge of the side walls 3. The infolding panel 3 thus .tas a width corresponding to the width of the side wall 3 and a height corresponding to the height of the main panel 5. The isosceles sides of the triangular infolding panel 8 are formed by crease lines 9 each of which extends from its point of intersection between the crease lines 4 and 6 and to a point located centrally between the crease lines 4 on a crease line 10 extending on a level with the upper edge of the main panel 5. Between the triangular infolding anels 8 and the rectangular main panels 5 are located triangular backfolding panels 11, each of which is limited by the crease line 7, the crease line 9 and a part of the crease line 10.

Above the described area of the tep of the packing container consisting of main panels 5, infolding panels 8 and backfolding panels 11, a number of sealing panels are present above the use· line 10 which in closed condition of the package form a sealing fin. The sealing panels termxr.ate the packing container at the top and comprise two sealing panels 12 located above the rectangular main panels 5 which have a width corresponding to the rectangular main panels. Between these two sealing panels 12 extend sealing panels 13 located above the top of the backfolding panels 11. The sealihg panels 13 which are a little lower than the sealing panels 12 are each divided by a vertical crease line 14 which extends from the meeting point of the crease lines 9 on the crease line 10 and vertically upwards to the top edge of the panels 13.

Fig.3 makes evident how certain parts of the surface of the packing material blank 2 are coated with an antifoacing agent.

The coating has been marked in the figures bv oblique hatching

AP 0 0 0 0 0 3

BAD ORIGINAL and the coated areas have H c-n ·ιι·. c.n reference r.'cri'.rji 15. The s which thereafter will oner at.a the nre iter coating 15 cavers tovirus t.'.e lr.t riot

particular frou rig. 3, ir aojoining the coated sealing panels 11. Ao in evident he preferred eruedimert where the coating consists of an anti framing as well its of ι seal-inhibiting agent, the coating 15 extends over two or more edge areas of the

cn.a another. The width of the coating in this area amounts to approx. 10 ism on either side of the respective crease line 7 which has been found to give good results, but the width may vary so that 10 - 401 of the surface of tha sealing panels 12,13 are covered by seal-inhibiting (.and antifcammg) agent. The coating 15 thus consists preferably of an agent which is anti foaming as well ?- seal-inhibiting, but it is also possible to use two different agents, namely an antifoaming agent which covers the backfolding panels 11 and parts of the main panels 5 and a seal-inhibiting agent which covers parts of the sealing panels 12 and 13. It is possible to apply both types of coating by means of a simple printing process in connection with the manufacture of the packing - -v ial. It is also possible to apply the agent by spraying or in some other known manner so that a coating of a thickness appropriate for the purpose, preferably approx. 0.5 - 3 g/m , is obtained.

When the packing container blank 2 in. accordance with fig. 3 is to be converted to a packing container in accordance with the invention the packing container blank is folded first along the crease lines 4 whereupon the two outer side wall panels 3 are joined to one another with the help of a sealing panel 16 extending along the crease line 4 of one of the side wall panels. The sealing takes place in a known manner by heating the appropriate parts of the thermoplastic layer of the packing material to such a temperature that the thermoplastic material softens whereupon the layers are pressed together and allowed tc cool. As a result

BAD ORIGINAL

- 8 a liquid-tight vertical seal is formed which imparts to the racking material blank the shape of a tube of substantially square crosssection. Tb.sn the base of the packing container is formed in that the bottom wail ccnels (not shown) designed in conventional manner are folded towards each other and heat-sealed so as to form a liquid-tight, substantially plane base. After this has been done the packing container can be filled with contents to a suitable level which substantially coincides with the main body of the packing container and the crease line 6 separating the top part. After filling with the required amount of contents has been completed the packing container is closed by folding down and sealing to one another the wall panels forming the top of the packing container.

The forming of the top of the packing container more particularly is realized by folding down the triangular panels 8 in the direction of the centre of the packing container at the same time us the rectangular main panels 5 are folded down towards each other and a swivelling movement is imparted to the triangular backfolding panels 11 connecting the panels 5 with the panels 8. In fully closed position (fig.l) the two main panels 5 like the triangular infolding panels 8 located under them, are inclined towards one another in pairs whereas the backfolding panels 11 r -ocated at sone distance under the main panels 5. In this manner between the main panels 5 and the backfolding panels 11 a channel which gradually narrows in upwards - outwards direction is formed, whose width at the end (facing towards the interior of the package at crease line 9) amounts to approx. 5 mm, then to taper off gradually in the direction towards the upper corner of the backfolding panel 11 which is formed by the crease lines 7 and 1C (where the width of the channel is approx. 1 ran) . The surfaces forming the channeL, that is to say the sides of the backfolding panels 11 facing towards the interior of the packing container and the corresponding triangular parts of the main panels 5 are preferably both (wholly or partly) coated with the antifoaming agent which together with the geometrical form of the channel results in a very good antifoaming effect. Moreover, bad ORIGINAL

AP 0 0 0 0 0 3

AP j since the channel extends at ,-n ar.jii to the vortical plane, a labyrinth function is cr^itcj .·ftctively prevents the concent- from g.tting up to the f:n f.· rm.-.d by the seiiin; panels 3 2,13 when the pct^i .j cent nn-?r io suojeoted to in.-ccm i<r shaking.

After the ten cart of tec picking icnini,or r.„t been formed through ioldir. i i'i of tnc atffeient panels farm.ng th< top part thj shape c: the top part is tide· pern,'.rent z/ sealing parts cf the surfaces cf the sealing ctr-eis 12,13 lying against one another by convent;anal heat sealing. Since the packing container in accordance with the invention is to be provided in its upper part with one or more pressure-ecuaiizir.g openings tst sealing panels 12,13 as described earlier have been coated w*th a seal-inhibiting and possibly also antifeaming agent. In the preferred embodiment cf the packing container in accordance with the invention, four individual pressure-equalizing openings 17 are formed accordingly wnich extend along each of the vertical crease lines 7. On sealing together of the sealing panels 12,13 to form the sealing fin of the packing container the coating 15 prevents the sealing together of the sealing panels 12,13 in the said areas extending along the crease lines 7 which means that the two sealing panels 12 are ^c- zed together only in a central area whilst approx. 10 ram .a openings are formed adjacent to the crease lines 7. The folded in sealing panels 13 situated in between are sealed to the sealing panels 12 only in their central part situated on either side of the crease lines 14, which mean, that here too non-sealed areas ire present along the crease lines 7. Owing to the coating pattern on the preferred embodiment of the packing container in accordance with the invention shown, feur individual pressure30 equalizing openings are thus produced between the different layers in the otherwise sealed up sealing fin.

Fig.2 demonstrates how the sealed areas and the surfaces coated with seal-inhibiting and/or antifoaoing agent relate to each other. In the central portion of the sealing fin the differ35 ent sealing panels 12,13 are sealed to one another which is appropriate, since the contents have direct access via the top fiAo original &

- 10 part of oh--· pacxLr.g ccr.t2ir.er to tins area 2.id therefore car. easily r. it·’ through possible leaks. The prcrsure-equali sing open in. j; on ::-: ether bits :r·:· s; tuutc.i at both ends of the Staling tin tri connection with the ir.tericr of the packing ton5 tainer is pcssible only via the channels cxtcacl.-.a between the back folding panels 11 an 1 adjoining parts of the main panels S.

Since tine wails of the channels arc coated with the antifoaming agent, an eftt ;tive c'no.-ical fc.m-killinq is obtained in the first place, whilst in addition any foam forcing its way up receives a m±chanical treatment owing to the narrowing shape of the channel. Each of the four pressure-equalising openings 17, as mentioned previously, has a width of approx. 10 mm, but the area cf the openings can vary as a function of the actual pressure in the packing container and the quantity of carbon dioxide which happens to escape at the particular moment. When no pressure or no significant pressure prevails in the packing container the ^russure-squalizing openings are kept substantially shut owing to the flexibility of the packing material, whereas the openings can be widened when the pressure in the package increases owing to shaking or increased temperature until the excess pressure has been reduced. It has been found in practice that the pressureequalicing openings are rarely opened at the same time, but that

:.s good as all cases they open successively one after the other. This is an inherent advantage in the arrangement having a number cf pressure-equalizing openings, since each of these can be given a relatively small area which prevents unintentional leakage of the contents when the packing container tilts over.

Likewise any risk of foreign objects penetrating into the packing container through the 'pressure-equalizing openings is largely eliminated.

The coating pattern for the anti foaming and seal-inhibiting agent may also be given a different geometrical shape or extent.

Where no seal-inhibiting agent is used (or where it is applied in a separate operation) it is particularly advantageous to apply the antifoaxing agent in a bandlike area along and directly below the crease line 10, since the application then does not have to be

BAD ORIGINAL A £ 0 0 0 0 0 dV done in register with the panels and crease lines of the blank. The width cf the - •'..-•si ik·? re: car. be varied as a fir.cticn of the required fnn-killmg effect.

The antifoaming agent may ice cf different types -polyvinyl 5 alcchcl, alg_nate etc.), but since in accordance wren a preferred embodiment of the invention it is desirable to be able to make use cf agents cf a single kind to obtain the antifoaming as well as the

seal-rmmcrng effect	, the available si	.ipply of suitable	agents
is somewhat limited.	It has been found	in practice that	the use
10 cf a polyvinyl alcohol	with a degree cf	hydrolysis of 30	- 95% is
advantageous. Especia	liy suitable is a	polyvinyl alcohol	with

a degree of hydrolysis cf 36%. This type of polyvinyl alcohol also has seal-inhibiting properties and the seal-inhibiting agent therefore may also be constituted of polyvinyl alcohol. As a result the coating fcr the purpose cf foam-killing as well as of seal-inhibiting can be done in one operation which appreciably facilitates and renders less expensive the manufacture of packing containers in accordance with the invention. A layer of polyvinyl alcohol cn the parts of the sealing panels 12,13 between which the pressure-equalizing openings are to be formed thus prevents effectively the fusing together and sealing of the thermoplastic lay;— _ the packing laminate within this area, at the same time as on contact with the polyvinyl alcohol coating any foam formed by the contents is reduced to iicuid which runs back into the packing container.

As an alternative to the seai-inhib_ting layer cn parts of the sealing panels 12,13 the sealing in these arees can be prevented also in ether ways cf course, e.g. in that these areas ere prevented from being heated during the sealing of the top part.

It can be advantageous however to retain the seal-inhibiting areas all the same, since this makes it even more certain that the pressure-equalising openings will be formed and will operate in the intended manner.

As mentioned previously the packing container and th« cieui*.

in accordance with the invention may be of a particularly' varied geometrical design and it is only necessary for the attainment bad original «V

- 12 of the object which forms the basis of the invention that the be provided with one or an anti foaming agent me. In practical upper pirt of the pocking container should aore pressure-equalizing openingo and that is placed in the packing container inside the experiments it has been found thio the packing container ^!n accordance with the invention serves it'· purpose very well and is especially suitable for the packaging of goods developing gas and ter. ling co foam such as Sorghum. beer.

APO 0 0 0 0 3

BAD ORIGINAL ft

Claims

1. A packing ontai.'.er, characterized in that if is provided witu a prezuure-ezpuali in/ opening (17) arranged between a number of material layers (12,13) forming the upper part of the packing container (1) which are sealed together for the purpose of closing the packing container but are partly non-sealed so as to form the said pressure-equalizing opening (17), and en antifoaming agent located in the packing container.

2. A packing container in accordance with claim 1, characterized in that the pressure-equalizing opening (17) at ito part facing towards the interior of the packing container (1) connects to a space wherein at least one boundary surface is coated with the antifoaming agent.

3. A packing container in accordance with one or more of the preceding claims comprising a ridgelike top part with two main panels (5) inclined towards each other, two triangular panels(8) located under these, also inclined towards each other, and backfclding panels (11) joining together the main panels and the infolding panels, characterized in that an arrangement for preventing the emanating of liquid foam is provided between the contents space proper of the packing container (1) and the ^essure-euqalizing opening (17), this arrangement comprising gradually narrowing channel which is formed between a main panel and adjoining backfolding panels (11), the walls of the channel being coated at least partly with antifoaming agent.

4. A packing container in accordance with claim 3, characterized in that the pressureequalizing opening is located at the upper end of the main panels (

5) where sealing panels (12,13) known in themselves are sealed to one another in their central part whilst non-sealed areas at the ends of the sealing panels form the said pressure-equalizing opening (17)-

BAD ORIGINAL

- 14 5. Λ packing container in accordance with claifi 4, characterized in that because of the flexibility of the packing material the pressure-equalizing openings (17) normally are kept nearly closed, whereas the pressure-equalizing openings are widened when the pressure in the packing container increases until the excess pressure has been reduced.

6. A packing container in accordance with one or more of the preceding claims, characterized in that the antifoaming 3ger,t is polyvinyl alcohol with a degree of hydrolysis of 80 - 95%.

7. A packing container in accordance with claim 5, characterized in that the polyvinyl alcohol h33 a degree of hydrolysis of 83».

8. A packing container in accordance with one or more of claims 1 to 5 inclusive, characterized in that the antifo3ming agent is an alginate.

9. A packing container in accordance with claim 1 or 4, characterized in that the said non-sealed area is coated with a seal-inhibiting agent.

10. A packing container in accordance with claim 9, characterized in that the seal-inhibiting agent consists of polyvinyl alcohol.

11. A blank for the manufacture of packing containers in accordance with one or more of the preceding claims,