WO2013004417A1

WO2013004417A1 - Lid, especially an aluminium lid, and a laminate for the production thereof, and a method

Info

Publication number: WO2013004417A1
Application number: PCT/EP2012/058426
Authority: WO
Inventors: Arnold Schneider; Eddy Daelmans; Arno Holzmüller; Karoline SEIBEL
Original assignee: Huhtamaki Ronsberg, Zweigniederlassung Der Huhtamaki Deutschland Gmbh & Co. Kg
Priority date: 2011-07-07
Filing date: 2012-05-08
Publication date: 2013-01-10
Also published as: DE102011106863A1

Abstract

The invention relates to a lid, especially an aluminium lid, wherein the lid (10) has a layer-like structure with at least two aluminium layers (20), at least one plastics layer (40) arranged between the aluminium layers (20), and a sealing layer (50), especially a heat-sealing layer, which forms an outermost layer of the lid (10), and to a laminate and to the production thereof for the production of such a lid.

Description

"Lid, especially an aluminium lid, and

a laminate for the production thereof, and a method"

Description

The invention relates to a lid, especially an aluminium lid, in accordance with the preamble of patent claim 1 , and to a laminate for the production of such a lid in accordance with the preamble of patent claim 13, and to a method of producing a laminate for the production of such a lid in accordance with the preamble of patent claim 16.

Lsds, such as, for example, aluminium lids, are frequently needed for covering and closing containers, such as, for example, yoghurt pots, or for providing, for example, tamper-evident closures on bottles and tubes.

For the production of such lids in accordance with the prior art, a relatively thick aluminium strip having a thickness in the range of from a minimum of 30 pm to usually approximately 70 μηι or more is printed on one side in order to provide the external design of the lid. A heat-seal lacquer is then applied to the side opposite from the printing, which heat-seal lacquer can be used to attach the iater lid to the container being closed. Once that heat-seal lacquer has been applied, the iid is then punched out from the coated aluminium strip in the desired shape and size, and Iater, in the form of a blank, sealed onto pots, bowls, bottles or tubes or other containers that can be closed with such a lid. These known aluminium lids have been found to have the disadvantage, however, that the production of such lids requires a very large amount of aluminium, which is necessary in order to be able to produce a lid of sufficient thickness which, in turn, is necessary if the lid is to have sufficient rigidity and flatness so that it can be sealed onto a container to be closed. A reduction in the thickness of the aluminium strip in order to reduce the cost of the lids, which have been very expensive hitherto on account of the very high aluminium requirement, has been possible only to a very limited extent hitherto in accordance with the prior art because an aluminium strip having a layer thickness of less than 30 μηι is no longer sufficiently rigid and is unable to ensure a lid of adequate flatness, so that the lid rolls up and, on closure of a container being closed, there is a risk that such a lid cannot be properly sealed to the container being closed, which in turn results in the loss of both the container and its contents. Furthermore, such a lid having a reduced thickness of aluminium in accordance with the prior art is also disadvantageous in respect of its stability.

The problem underlying the invention is to provide a lid, especially an aluminium lid, which avoids, i.e. does not have, the above disadvantages and, furthermore, is simple and economical to produce with a low aluminium requirement, and which also has improved mechanical and physicochemical properties.

That problem is solved by a lid in accordance with patent claim 1 and by a laminate for the production of such a lid in accordance with patent claim 13 and by a method of producing a laminate for the production of such a lid in accordance with patent claim 16.

In particular, the problem is solved by a lid, especially an aluminium lid, wherein the lid has a layer-like structure with at least two aluminium layers, at least one plastics layer arranged between the aluminium layers, and a sealing layer, especially a heat-sealing layer, which forms an outermost layer of the lid.

An important aspect of the invention lies in the fact that there is used for the lid according to the invention not merely a thick aluminium layer, as in the prior art, but a plurality of aluminium layers, preferably two aluminium layers, arranged on either side of a plastics layer. By virtue of that arrangement it is possible, as has been found according to the invention, for the two aluminium layers to be considerably thinner than the aluminium layer necessary for the production of an aluminium lid hitherto, so that the amount of aluminium required for the lid according to the invention, or rather the blank according to the invention, is significantly reduced in comparison with the prior art. In particular, it is also possible according to the invention for the cumulative layer thickness of the aluminium iayers necessary for the lid according to the invention to be significantly thinner than the previously necessary thickness for an aluminium lid required hitherto.

Accordingly, the provision of such a lid according to the invention is associated with a marked reduction in costs, because the amount of aluminium required according to the invention is substantially reduced and now lies in the range of from 10 % to a maximum of 50 % of the original amount of aluminium required in accordance with the prior art.

Furthermore, in comparison with conventional aluminium lids, the lid according to the invention has numerous further advantages which are advantageously revealed, for example, in the lid's markedly increased resistance to tearing, especially when a container is opened. Such increased resistance to tearing firstly results from the provision of two aluminium Iayers instead of only one aluminium layer and especially results from the plastics layer arranged between the aluminium Iayers, which plastics layer prevents tearing, or further tearing, on opening of a container closed with such a lid according to the invention.

Furthermore, an afore-mentioned lid according to the invention has a markedly higher barrier action with respect to gaseous substances, which is again a result of there being two aluminium Iayers instead of one aluminium layer. Furthermore, between those aluminium Iayers there can also be introduced one or more further barrier layer(s), for example made of ethylene vinyl alcohol copolymer, polyamide, silicon oxide and/or aluminium oxide. A further advantage of the lid according to the invention is that, in comparison with conventional lids, it has significantly increased flexural strength which can be varied according to the invention in a very simple way, namely by means of the spacing of the two aluminium Iayers from one another or by means of the thickness, type or number of aluminium Iayers and of plastics Iayers arranged between the aluminium iayers. Furthermore, the lid according to the invention is also especially suitable for attachment to uneven sealing surfaces of containers, because the plastics layer arranged between the aluminium layers serves as a compensating layer, so that the lid according to the invention is especially well able to adapt to such uneven surfaces in the same way as a cushion or a "pillow foil" and can be sealed to such surfaces with the outermost layer of the lid according to the invention, which layer is in the form of a sealing layer, the thin layer of aluminium used, which allows such adaptation, again being advantageous here. According to the invention, the sealing layer comprises a polyethylene or polypropylene or a heat-seal lacquer, it being possible, as desired and in accordance with the field of application, for the sealing layer to be applied over all or part of the surface, especially in an edge region of the lid, and for a sealing material optionally to have a linear and/or doited pattern. As a result of such a partial and/or patterned application of the sealing material it is possible for a new type of fid according to the invention to be produced in a way that is very conserving of resources, especially materials, and that is cost- effective, while at the same time the properties of the lid in respect of resistance to tearing, sealing and handling during mounting of a lid, but also in the context of opening a container closed with the lid, are optimised.

In accordance with a preferred embodiment of the invention, the two aluminium layers are of substantially identical thickness. Such an embodiment ensures that the lid according to the invention lies substantially perfectly flat, it also being possible in accordance with a further embodiment for the two aluminium layers to be of different thicknesses. In that case, one of the two aluminium layers can have a thickness in the range of from 65 % to 100 %, preferably in the range of from 75 % to 00 % and especially in the range of from 85 % to 98 % of the thickness of the other aluminium layer. Such an embodiment is especially advantageous for containers having a container opening of three-dimensional design, to which the lid according to the invention is to be sealed. Furthermore, such a lid having two aluminium layers of slightly different thicknesses can be used, for example, in the context of rolling up and sealing onto a container opening that is, for example, of irregular shape.

A further advantage of the use of aluminium layers of different thicknesses is also beneficial when the lid according to the invention, or rather the blank according to the invention, does not have a substantially symmetrical structure, because in that case it is nevertheless possible, by means of aluminium layers of different thicknesses, to obtain a substantially perfectly flat lid.

As materials for the plastics layer there are suitable according to the invention especially polyesters, such as, for example, polyethylene terephthalate, or polyolefins, such as, for example, polyethylene or polypropylene, with preferably biaxially oriented polyesters or polyolefins again being preferred here, if unintentional tearing of the lid is to be avoided, because those materials have a high degree of resistance to tearing. For the case where such a lid is to be torn open or torn off in a specific way, it is also possible, however, to use a unidirectionally stretched polyester or such a stretched po!yoiefin, especially polypropylene, a stretching factor in the range of from 3 to 6 being preferred in this case.

Furthermore, it is advantageous according to the invention for an adhesion promoter, especially an adhesive layer, to be arranged between the or a plastics layer(s) and an adjacent aluminium layer. In that way, the mechanical stability of the lid according to the invention can be further increased.

In accordance with a further preferred embodiment of the invention, the lid, leaving out of consideration the sealing layer, which serves merely for attaching the lid to a container to be closed, is of substantially symmetrical construction in respect of a plastics layer arranged innermost in the layer-like structure. Such a structure ensures that the lid according to the invention lies flat, so that the attachment, especially sealing attachment, of the lid according to the invention to a container or to an opening is especially simple to carry out.

In respect of the individual layer thicknesses of the lid according to the invention, aluminium layers having individual layer thicknesses in the range of from 2 pm to 15 pm, preferably in the range of from 3.5 pm to 12 pm and especially in the range of from 4.5 pm to 8 pm have proved particularly advantageous. The plastics layer(s) has/have an individual layer thickness in the range of from 5 pm to 50 pm, preferably in the range of from 8 pm to 40 pm and especially in the range of from 10 pm to 35 pm. Observing those layer thicknesses for the plastics layer(s) is especially advantageous with a view to the fiexural strength and the resistance to tearing of the lid according to the invention. Moreover, in accordance with one embodiment of the invention the aluminium layers, leaving out of consideration the sealing layer and any printing arranged on an outer side of the lid, are in each case the outermost layers of the lid. In accordance with a preferred embodiment of the invention, at least one of the aluminium layer(s) (20) is provided on at least one side, preferably on an outer side, with an embossed and/or mat and/or glossy, especially high-gloss, finish; embossing of the lid, which is provided, for example, on an outer side of the lid and results in slight unevenness of the embossed surface, is especially advantageous for the handling of the lid according to the invention, since such lid blanks are particularly easy to take from a stack of lid blanks and do not adhere to one another undesirably. It should be mentioned here that, within the scope of this invention, other methods with which slight unevenness can be created in the surface of such a lid, such as, for example, the application of ink, also fall under the term "embossing" in functional terms.

Furthermore, as a result of the embossed, mat and/or glossy configuration of the lid according to the invention it is possible to realise lids of especially attractive appearance, it being possible to use such configurations also in combination with one another, either for both aluminium foils or only for one and/or the other aluminium foil. Moreover, such configurations of the lid can also serve for identifying the inner and outer sides of the lid.

Moreover, the problem of the invention is solved, in particular, also by a laminate for the production of a lid as described above, the laminate having a layer-like structure with at least two aluminium layers and at least one plastics layer arranged between the aluminium layers, and optionally a sealing layer, especially a heat-sealing layer, which forms an outermost layer of the laminate.

According to one embodiment according to the invention, at least one of the aluminium layer(s) (20) of the laminate is provided on at least one side, preferably on an outer side, with an embossed and/or mat and/or glossy, especially high-gloss, finish, in order to be able to create a lid as described above.

Such a laminate can be produced in an especially simple way using existing laminating machines for aluminium laminates, it advantageously being possible to produce fids of any desired form simply and quickly from such a laminate, for example by punching. Furthermore, a method for producing a laminate as described above, especially for the production of a lid (10) according to the invention, serves for implementing the invention in a particularly simple way, wherein at ieast one of the aluminium layer(s) (20), prior to being joined to at Ieast one plastics layer (40) and/or sealing layer (50), is provided on at Ieast one side, preferably on an outer side, with an embossed and/or mat and/or glossy, especially high-gloss, finish.

Further embodiments of the invention will be found in the subsidiary claims.

The invention is described below on the basis of an exemplary embodiment which is explained in greater detail with reference to the Figures, wherein

Fig. 1 shows an aluminium lid in accordance with the prior art; and

Fig. 2 shows a lid in accordance with an embodiment of the invention.

In the description hereinbelow, parts that are the same or have the same action have been given the same reference numerals.

Fig. 1 shows an aluminium lid in accordance with the prior art. The aluminium lid 10 has an aluminium layer 20 which, shown at the bottom in Fig. 1 , is provided with a sealing layer 50. In the case of this !id in accordance with the prior art, the layer thickness of the aluminium layer 20 is 70 m in order that the lid has sufficient rigidity and flatness, as is necessary in order that the lid can be attached to containers without problems.

Fig. 2 shows an embodiment of a lid according to the invention. The lid 10 is of multi- layered construction and has an aluminium layer 20 outermost, that is to say on what is later its outer side after attachment to a container. This aluminium layer has a layer thickness of 6 pm and is joined to a plastics layer 40 made of biaxially oriented polypropylene by means of an adhesive layer 30. The other side of the plastics layer 40 is in turn provided with an adhesive layer 30 with which the plastics layer 40 is joined to a second aluminium layer 20. That further aluminium layer 20 likewise has a layer thickness of 6 μητι, while the plastics layer 40 has a layer thickness of 10 pm. Accordingly, the lid according to the invention is of symmetrical construction in respect of the plastics layer 40, the two aluminium layers 20 each being arranged outermost. For attaching this lid according to the invention to a container, furthermore, the aluminium layer 20 shown at the bottom in Fig. 2 is provided with a sealing layer 50. That sealing layer 50 can be, for example, a heat-seal lacquer or co-extruded peelable polyethylene; depending upon the field of application, however, there also come into consideration here other sealing or adhesive media, such as, for example, a cold adhesive, for example if the container is to be reclosable.

It should be pointed out here that all the parts described above, considered on their own or in any combination, especially the details shown in the drawings, are claimed as being important to the invention. Modifications thereof are familiar to the person skilled in the art.

Reference n umerals

10 lid

20 aluminium layer

30 adhesive layer

0 plastics layer

50 sealing layer

Claims

Patent cla ims

1. Lid, especiaf!y an a!uminium lid,

characterised in that

the lid (10) has a layer-like structure with at least two aluminium layers (20), at least one plastics Iayer (40) arranged between the aluminium layers (20), and a sealing Iayer (50), especially a heat-sealing iayer, which forms an outermost Iayer of the lid (10).

2. Lid according to claim 1,

characterised in that

the two aluminium layers (20) are of substantially identical thickness,

3. Lid according to claim 1 ,

characterised in that

one of the two aluminium layers (20) has a thickness in the range of from 65 % to 100 %, preferably in the range of from 75 % to 100 % and especially in the range of from 85 % to 98 % of the thickness of the other aluminium layer (20).

4. Lid according to any one of the preceding claims,

characterised in that

a material of the plastics Iayer (40) is selected from a polyester, especially polyethylene terephthalate, or a polyolefin, especially polyethylene or polypropylene.

5. Lid according to any one of the preceding claims,

characterised in that

an adhesion promoter, especially an adhesive Iayer (30), is arranged between the plastics layer (40) and an adjacent aluminium Iayer (20).

6. Lid according to any one of the preceding claims,

characterised in that

the lid (10), leaving out of consideration the sealing iayer (50), is of substantially symmetrical construction in respect of a plastics iayer (40) arranged innermost in the layer-like structure. Lid according to any one of the preceding claims,

characterised in that

the aluminium layers (20) each have an individual layer thickness in the range of from 2 pm to 15 pm, preferably in the range of from 3.5 pm to 12 pm and especially in the range of from 4.5 pm to 8 pm.

Lid according to any one of the preceding claims,

characterised in that

the plastics layer(s) (20) has/have an individual layer thickness in the range of from 5 pm to 50 pm, preferably in the range of from 8 pm to 40 pm and especially in the range of from 10 pm to 35 pm.

Lid according to any one of the preceding claims,

characterised in that

the aluminium layers (20), leaving out of consideration the sealing layer (50) or any printing, are in each case the outermost layers of the lid (10).

Lid according to any one of the preceding claims,

characterised in that

at least one of the aluminium layer(s) (20) is provided on at least one side, preferably on an outer side, with an embossed and/or mat and/or glossy, especially high-gloss, finish.

Lid according to any one of the preceding claims,

characterised in that

the sealing layer (50) comprises polyethylene or polypropylene or a heat-seal lacquer.

Lid according to any one of the preceding claims,

characterised in that

the sealing layer (50) is applied over part of the surface, especially in an edge region of the lid (10), and a sealing material optionally has a linear and/or dotted pattern. - i l ls. Laminate for the production of a Sid (10) according to any one of the preceding claims,

characterised in that

the laminate has a layer-like structure with at least two aluminium layers (20) and at least one plastics layer (40) arranged between the aluminium layers (20), and optionally a sealing layer (50), especially a heat-sealing layer, which forms an outermost layer of the laminate,

14. Laminate according to claim 13,

characterised in that

15. Laminate according to either one of preceding claims 13 and 14,

characterised in that

the laminate is punchable.

16. Method of producing a laminate according to any one of preceding claims 13 to 15, especially for the production of a lid (10) according to any one of preceding claims 1 to 12,

characterised in that

at least one of the aluminium iayer(s) (20), prior to being joined to at least one plastics layer (40) and/or sealing layer (50), is provided on at least one side, preferably on an outer side, with an embossed and/or mat and/or glossy, especially high-gloss, finish.