LEAST PARTLY DIFFERENT PH, ESPECIALLY FOR PRODUCING A CARRIER LAYER

The present invention relates to a method comprising as method steps

a) providing

i) a first composition having a first pH, said first composition including

A) water in a first water content,

B) a first multitude of fibres, and

C) a first sizing agent,

ii) a second composition having a second pH, said second composition including

A) water in a second water content,

B) a second multitude of fibres, and

C) a second sizing agent, and

iii) a third composition having a third pH, said third composition including

A) water in a third water content,

B) a third multitude of fibres, and

C) the first sizing agent or a third sizing agent or both; and b) generating of a layer sequence including, as mutually superposed layers in this se quence,

i) a first sheetlike layer,

ii) a second sheetlike layer, and

iii) a third sheetlike layer;

wherein the method step b) comprises

a. generating the first sheetlike layer from the first composition, said generating comprising reducing the first water content, b. generating the second sheetlike layer from the second composition, said gen erating comprising reducing the second water content, and c. generating the third sheetlike layer from the third composition, said generat ing comprising reducing the third water content;

wherein, in the method step a), the first pH or the third pH or each of them is lower than the second pH. The invention further relates to a carrier layer obtainable by this method; to a sheet like composite comprising this carrier layer; to a method in which a sheetlike composite is ob tained; to said sheetlike composite; to a container precursor and to a container each comprising the aforementioned carrier layer or one of the aforementioned sheetlike composites; to a use of the carrier layer; and to a use of first to third compositions for production of a cardboard, paper- board or paper layer.

For some time, food and drink products, whether they be food and drink products for human consumption or else animal feed products, have been preserved by storing them either in a can or in a jar closed by a lid. In this case, the shelf life can be increased firstly by sterilizing the food or drink product and the container, here the jar or can, separately and to the greatest possible extent in each case, and then introducing the food or drink product into the container and closing the container. However, these measures for increasing the shelf life of food and drink products, which have been tried and tested over a long period, have a series of disadvantages, for example the need for another sterilization later on. Cans and jars, because of their essentially cylindrical shape, have the disadvantage that very dense and space-saving storage is not possible. Moreover, cans and jars have considerable intrinsic weight, which leads to increased energy expenditure in transport. In addition, production of glass, tinplate or aluminium, even when the raw materials used for this purpose are recycled, necessitates quite a high expenditure of energy. In the case of jars, an additional aggravating factor is elevated expenditure on transport. The jars are usually prefabricated in a glass factory and then have to be transported to the facility where the food and drink products are dispensed with the use of considerable transport volumes. Furthermore, jars and cans can be opened only with considerable expenditure of force or with the aid of tools and hence in a rather laborious manner. In the case of cans, there is a high risk of injury arising from sharp edges that occur on opening. In the case of jars, there are recurrent instances of broken glass getting into the food or drink product in the course of filling or opening of the filled jars, which in the worst case can lead to internal injuries when the food or drink product is consumed. In addition, both cans and jars have to be labelled for identification and promotion of the food or drink product contents. The jars and cans cannot readily be printed directly with information and promotional messages. In addition to the actual print, a substrate for the print, a paper or a suitable film, is thus needed, as is a securing means, an adhesive or a sealant.

Other packaging systems for storing food and drink products over a long period with minimum impairment are known from the prior art. These are containers produced from sheetlike compo sites - frequently also referred to as laminates. Sheetlike composites of this kind are typically constructed from a thermoplastic polymer layer, a carrier layer that imparts dimensional stability to the container, an adhesion promoter layer, a barrier layer and a further thermoplastic polymer layer, as disclosed inter alia in WO 90/09926 A2. Since the carrier layer imparts dimensional stability to the container manufactured from the laminate, these containers, by contrast with film bags, can be regarded as a further development of the aforementioned jars and cans. At the same time, these laminate containers already have many advantages over the conventional jars and cans. Nevertheless, there are opportunities for improvement in the case of these packaging sys tems too.

Since the above laminates are always constructed from multiple layers of different materials, a challenge for these laminates is for the adhesion between these layers to be sufficiently great to prevent delamination of individual layers even in the processing of the laminate by means of grooving and folding and after a certain storage time of the container produced therewith, in which it can be exposed to various conditions such as cold, heat or moisture. If there is partial delamination of individual layers in the laminate, this can lead to further damage to the laminate layers under mechanical stress on the laminate, for example on grooving and folding. Especially damage to the barrier layer can lead to elevated ingress of oxygen into the container, which in turn contributes to quality impairments of the food or drink product and hence a shortened shelf life. Delamination can also result in formation of channels or cavities in the laminate, in which microbes can accumulate or penetrate into the container and can more easily spoil the food or drink product present in the container. These microbes in small defects in the containers cannot be countered even by stronger sterilization of the food and drink products. Even attempted stronger sterilization of the container prior to filling with food or drink product barely leads to the desired long storage times. In addition to the individual layers of laminate, the carrier layer typically consists of multiple plies. Cardboard is often used as the carrier layer. This typically has at least 3 plies: a top ply, a middle ply and a back ply. These plies too must be bonded to one another with adequate bond strength. Moreover, cardboard as a material is fundamentally liquid absorbing, which fundamentally constitutes a challenge in the case of use in a laminate from which containers for storage of liquid food or drink products such as beverages and soups are to be produced. Moreover, the laminate can have cut edges particularly on the outside of the con tainer where the carrier layer is not protected by the surrounding layers of laminate and hence is exposed to ambient humidity. Nevertheless, the use of cardboard as carrier layer appears desir able owing to other advantageous properties, for example its processability, its low weight, the fact that it is obtained from largely renewable raw materials. Consequently, the aforementioned challenge is met in the prior art by partial hydrophobization of the cardboard by means of sizing, especially internal sizing. For this purpose, a multitude of sizing agents is known in the prior art. In the context of the invention, it has been found that, surprisingly, the properties of a laminate for production of dimensionally stable food or drink product containers can be improved by modifying the production of the carrier layer composed of various plies in the manner described below which, to the knowledge of the inventors, is unknown in the prior art.

In general terms, it is an object of the present invention to at least partly overcome a disadvantage that arises from the prior art. It is a further object of the invention to provide a carrier layer for production of dimensionally stable containers that are suitable for storage of liquid food or drink products with maximum shelf life. In addition, it is an object of the invention to provide a carrier layer for production of dimensionally stable food or drink product containers from a multilayer sheetlike composite comprising the carrier layer, wherein the composite has a maximum dura tion of an adhesion and maximum adhesion of polymer layers, especially of polyolefin layers, especially polyethylene layers, applied by means of layer extrusion, of the composite to the car rier layer. At the same time, the sheetlike composite preferably has a minimum tendency to absorb liquid, especially at cut edges of the composite. It is a further object of the invention to provide one of the aforementioned advantageous carrier layers, wherein a minimum level of rejects arise in a production and transport of a multilayer sheetlike composite comprising the carrier layer in rolled-up form. In addition, it is an object of the invention to provide a carrier layer for a multilayer sheetlike composite for production of dimensionally stable food and drink product containers, wherein the carrier layer, even after prolonged storage, can be processed, for example grooved, folded, cut to size or printed, in an as simple and as precise as possible manner. It is a further object of the invention to achieve one or more of the abovementioned objects using sizing agents that are customary in cardboard, paperboard or paper production. It is a further object of the invention to achieve one or more of the aforementioned objects, wherein the carrier layer additionally has an as simple as possible construction, especially a minimum number of plies. In addition, it is an object of the invention to provide a multilayer sheetlike composite for production of dimensionally stable food and drink product containers having one of the afore mentioned advantageous carrier layers. In a further object of the invention, one or more of the aforementioned objects are achieved, wherein the sheetlike composite can be used to produce a dimensionally stable food or drink product container with minimum intrinsic weight. It is a fur ther object of the invention to achieve one or more of the aforementioned objects, wherein the sheetlike composite can be used to produce a dimensionally stable food or drink product con tainer of an as simple as possible construction.

A contribution to the at least partial achievement of at least one, preferably more than one, of the above objects is made by the independent claims. The dependent claims provide preferred embodiments which contribute to the at least partial achievement of at least one of the objects.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a method 1 comprising, as method steps,

a) providing

i) a first composition having a first pH, said first composition including

A) water in a first water content,

B) a first multitude of fibres, and C) a first sizing agent,

ii) a second composition having a second pH, said second composition including

A) water in a second water content,

B) a second multitude of fibres, and

C) a second sizing agent, and

iii) a third composition having a third pH, said third composition including

A) water in a third water content,

B) a third multitude of fibres, and

C) the first sizing agent or a third sizing agent or both; and b) generating of a layer sequence including, as mutually superposed layers in this se quence,

i) a first sheetlike layer,

ii) a second sheetlike layer, and

iii) a third sheetlike layer;

wherein method step b) comprises

a. generating the first sheetlike layer from the first composition, said generating com prising reducing the first water content,

b. generating the second sheetlike layer from the second composition, said generating comprising reducing the second water content, and

c. generating the third sheetlike layer from the third composition, said generating com prising reducing the third water content;

wherein, in the method step a), the first pH or the third pH or each of them is lower than the second pH. Preferably, the first and third pH in the method step a) are less than the second pH. Further preferably, the first pH or the third pH or more preferably each of them is less than the second pH also at least partly in the method step b). The second sizing agent is preferably dif ferent from the first sizing agent or the third sizing agent or from both.

Method steps a) and b) may, in method 1 according to the invention, be simultaneous, overlap in time or be successive in time. The sequence of steps a. to c. is not fixed by the above sequence of enumeration of these steps. Instead, all sequences in conceivable combinations are possible. In addition, it is possible for steps a. to c. to be simultaneous, to overlap in time or to be succes sive in time. In this case, steps a. to c. may be directly successive, but there may also be inter mediate steps between two of steps a. to c. Preferably, steps a. to c. are effected in one of the following sequences: a., b., c. or a., c., b. or b., a., c. or b., c., a. or c., a., b. or c., b., a. It is possible here firstly to generate one or more of the first to third sheetlike layers from the respec tive composition and then to superpose at least one of the layers generated with one of the other compositions, in order then to produce the respective sheetlike layer from the aforementioned other composition. Alternatively or additionally, it is possible to generate at least 2 of the first to third sheetlike layers and then to superpose them to one another. Mixed forms of the two aforementioned procedures are also conceivable. For example, it is possible, without restriction, first to generate the first and third sheetlike layers, then to superpose the first sheetlike layer with the second composition, then to generate the second sheetlike layer from the second composi tion, and then to superpose the third sheetlike layer to the second sheetlike layer.

In method step a), the first composition includes the first multitude of fibres; the second compo sition includes the second multitude of fibres; and the third composition includes the first mul titude of fibres, the third multitude of fibres, or the first and third multitude of fibres in total preferably in a proportion in the range from 0.01% to 10% by weight, more preferably from 0.01% to 9% by weight, more preferably from 0.01% to 8% by weight, more preferably from 0.01% to 7% by weight, more preferably from 0.01% to 6% by weight, more preferably from 0.01% to 5% by weight, more preferably from 0.1% to 5% by weight, more preferably from 0.1% to 4% by weight, more preferably from 0.1% to 3.5% by weight, more preferably from 0.1% to 3% by weight, more preferably from 0.1% to 2.5% by weight, most preferably from 0.2% to 2% by weight, based in each case on the total weight of the respective composition.

In one embodiment 2 of the invention, the method 1 is configured according to its embodiment 1, wherein the method is a method of producing a carrier layer. A preferred carrier layer is a cardboard, paperboard or paper layer, particular preference being given to a cardboard layer. In one embodiment 3 of the invention, the method 1 is configured according to its embodiment 1 or 2, wherein the first pH or the third pH or each of them is less than the second pH by at least 0.3, more preferably by at least 0.4, more preferably by at least 0.5, more preferably by at least

0.6, more preferably by at least 0.7, most preferably by at least 0.8. In a preferred embodiment of the method, the first pH or the third pH or each of them is not more than 1.5 less than the second pH. Preferably, the first pH and the third pH are each less than the second pH by at least

0.3, more preferably by at least 0.4, more preferably by at least 0.5, more preferably by at least

0.6, more preferably by at least 0.7, most preferably by at least 0.8.

In one embodiment 4 of the invention, the method 1 is configured according to any of its em bodiments 1 to 3, wherein the first pH or the third pH or each of them is less than 7, preferably less than 6.9, more preferably not more than 6.8. Preferably, the first pH and the third pH are each less than 7, more preferably less than 6.9, more preferably not more than 6.8.

In one embodiment 5 of the invention, the method 1 is configured according to any of its em bodiments 1 to 4, wherein the second pH is more than 7, preferably more than 7.1, more prefer ably more than 7.2, more preferably more than 7.3, even more preferably more than 7.4, most preferably more than 7.5.

In one embodiment 6 of the invention, the method 1 is configured according to any of its em bodiments 1 to 5, wherein the first pH or the third pH or each of them is in a range from 5.5 to 7.5, preferably from 5.7 to 7.4, more preferably from 5.9 to 7.3, more preferably from 6.1 to 7.2, more preferably from 6.2 to 7.1, more preferably from 6.3 to 7.0, more preferably from 6.4 to 6.9, more preferably from 6.5 to 6.9, even more preferably from 6.6 to 6.9, most preferably from 6.7 to 6.9. Preferably, the first pH and the third pH are in a range from 5.5 to 7.5, more preferably from 5.7 to 7.4, more preferably from 5.9 to 7.3, more preferably from 6.1 to 7.2, more preferably from 6.2 to 7.1, more preferably from 6.3 to 7.0, more preferably from 6.4 to 6.9, more preferably from 6.5 to 6.9, even more preferably from 6.6 to 6.9, most preferably from 6.7 to 6.9. In one embodiment 7 of the invention, the method 1 is configured according to any of its em bodiments 1 to 6, wherein the second pH is in a range from 7.0 to 8.5, preferably from 7.1 to 8.4, more preferably from 7.2 to 8.3, more preferably from 7.3 to 8.2, more preferably from 7.4 to 8.1, even more preferably from 7.5 to 8.0, most preferably from 7.6 to 7.9.

In one embodiment 8 of the invention, the method 1 is configured according to any of its em bodiments 1 to 7, wherein, in method step b., the generating of the second sheetlike layer from the second composition includes crosslinking of the second sizing agent from the second com position. This crosslinking can be effected simultaneously, with a time overlap, or before or after the reduction in the second water content. In the case that these steps are effected with a time overlap, the reduction of the second water content preferably commences prior to the crosslink ing of the second sizing agent, or vice versa. In the case that these steps are effected successively, the reduction of the second water content is preferably conducted prior to the crosslinking of the second sizing agent, or vice versa. The aforementioned crosslinking of the second sizing agent of the second composition preferably leads to sizing of the second multitude of fibres.

In one embodiment 9 of the invention, the method 1 is configured according to any of its em bodiments 1 to 8, wherein, in method step a., the generating of the first sheetlike layer from the first composition comprises increasing van der Waals binding forces between the fibres of the first multitude of fibres and the first sizing agent. The above increasing of the van der Waals binding forces preferably leads to sizing of the first multitude of fibres. Preferably, method step a. does not comprise crosslinking of the first sizing agent in the manner of a chemical reaction. Accordingly, the first sizing agent in method step a. preferably does not enter into any chemical crosslinking reaction.

In one embodiment 10 of the invention, the method 1 is configured according to any of its em bodiments 1 to 9, wherein, in method step c., the generating of the third sheetlike layer from the third composition comprises increasing van der Waals binding forces between the fibres of the third multitude of fibres and the first sizing agent or the third sizing agent or both, each from the third composition. The above increasing of the van der Waals binding forces preferably leads to sizing of the third multitude of fibres. Preferably, method step c. does not include crosslinking of the first sizing agent or of the third sizing agent or of each of them, each from the third com position, in the manner of a chemical reaction. Accordingly, the first sizing agent or the third sizing agent or both, each from the third composition, preferably does not enter into a chemical crosslinking reaction in method step c.

In one embodiment 11 of the invention, the method 1 is configured according to any of its em bodiments 1 to 10, wherein, in method step a), the first composition comprises the first sizing agent in a proportion in the range from 1 to 10 kg/ODT, preferably from 1 to 9 kg/ODT, more preferably from 2 to 8 kg/ODT, more preferably from 3 to 7.5 kg/ODT, even more preferably from 3 to 6 kg/ODT, most preferably from 4 to 5 kg/ODT, based in each case on the oven-dried first composition. In a further preferred embodiment, the first composition in method step a) comprises the first sizing agent in a proportion in the range from 2 to 10 kg/ODT, preferably from 3 to 10 kg/ODT, more preferably from 4 to 10 kg/ODT, more preferably from 5 to 10 kg/ODT, even more preferably from 6 to 9 kg/ODT, most preferably from 7 to 8 kg/ODT, based in each case on the oven-dried first composition. In this document, the abbreviation kg/ODT always stands for the unit kilograms per oven-dried ton , i.e. the proportion by mass in kg per ton of the oven-dried composition.

In one embodiment 12 of the invention, the method 1 is configured according to any of its em bodiments 1 to 11, wherein, in method step a), the third composition comprises the first sizing agent, or the third sizing agent, or each of them, or both together, in a proportion in the range from 1 to 10 kg/ODT, preferably from 1 to 9 kg/ODT, more preferably from 2 to 8 kg/ODT, more preferably from 3 to 7 kg/ODT, even more preferably from 3 to 6 kg/ODT, most preferably from 4 to 5 kg/ODT, based in each case on the oven-dried third composition. In a further pre ferred embodiment, the third composition in method step a) comprises the first sizing agent, or the third sizing agent, or each of them, or both together, in a proportion in the range from 2 to 10 kg/ODT, preferably from 3 to 10 kg/ODT, more preferably from 4 to 10 kg/ODT, more preferably from 5 to 10 kg/ODT, even more preferably from 6 to 9 kg/ODT, most preferably from 7 to 8 kg/ODT, based in each case on the oven-dried third composition.

In one embodiment 13 of the invention, the method 1 is configured according to any of its em bodiments 1 to 12, wherein, in method step a), the second composition comprises the second sizing agent in a proportion in the range from 0.5 to 10 kg/ODT, preferably from 1 to 9 kg/ODT, more preferably from 1 to 8 kg/ODT, more preferably from 1 to 7 kg/ODT, more preferably from 2 to 6 kg/ODT, even more preferably from 3 to 5 kg/ODT, most preferably from 3 to 4.5 kg/ODT, based in each case on the oven-dried second composition.

In one embodiment 14 of the invention, the method 1 is configured according to any of its em bodiments 1 to 13, wherein, in method step a), the first composition or the third composition or each of them includes less than 1 kg/ODT, preferably less than 0.5 kg/ODT, more preferably less than 0.2 kg/ODT, most preferably less than 0.1 kg/ODT, based in each case on the respective oven-dried composition, of the second sizing agent. Preferably, each of the first composition and the third composition includes less than 1 kg/ODT, preferably less than 0.5 kg/ODT, more pref erably less than 0.2 kg/ODT, most preferably less than 0.1 kg/ODT, based in each case on the respective oven-dried composition, of the second sizing agent.

In one embodiment 15 of the invention, the method 1 is configured according to any of its em bodiments 1 to 14, wherein, in method step a), the second composition includes less than 1 kg/ODT, preferably less than 0.5 kg/ODT, more preferably less than 0.2 kg/ODT, most prefer ably less than 0.1 kg/ODT, based in each case on the oven-dried second composition, of the first sizing agent, or of the third sizing agent, or both together, or of each of them. Preferably, the second composition includes less than 1 kg/ODT, preferably less than 0.5 kg/ODT, more pref erably less than 0.2 kg/ODT, most preferably less than 0.1 kg/ODT, based in each case on the oven-dried second composition, of the first sizing agent and the third sizing agent in sum. In one embodiment 16 of the invention, the method 1 is configured according to any of its em bodiments 1 to 15, wherein the first sizing agent comprises and preferably consists of a resin, or the third sizing agent comprises and preferably consists of a resin, or both.

In one embodiment 17 of the invention, the method 1 is configured according to any of its em bodiments 1 to 16, wherein the second sizing agent comprises and preferably consists of an ester.

In one embodiment 18 of the invention, the method 1 is configured according to any of its em bodiments 1 to 17, wherein the second sizing agent is an alkyl ketene dimer, or an alkenylsuc- cinic anhydride, or a mixture of the two.

In one embodiment 19 of the invention, the method 1 is configured according to any of its em bodiments 1 to 18, wherein the fibres of the first multitude of fibres have a first average fibre length, wherein the fibres of the second multitude of fibres have a second average fibre length, wherein the fibres of the third multitude of fibres have a third average fibre length, wherein the first average fibre length is different from the third average fibre length. Preferably, the first average fibre length differs from the third average fibre length by 0.1 to 3 mm, more preferably by 0.5 to 2.5 mm, most preferably by 1 to 2.0 mm. Preferably, the first average fibre length is less than the third average fibre length, preferably by 0.1 to 3 mm, more preferably by 0.5 to 2.5 mm, most preferably by 1 to 2.0 mm.

In one embodiment 20 of the invention, the method 1 is configured according to any of its em bodiments 1 to 19, wherein, in method step a), one selected from the group consisting of the first water content, the second water content and the third water content, or a combination of at least two of these, is in a range from 90% to 99.99% by weight, preferably from 91% to 99.99% by weight, more preferably from 92% to 99.99% by weight, more preferably from 93% to 99.99% by weight, more preferably from 94% to 99.99% by weight, more preferably from 95% to 99.99% by weight, most preferably from 95% to 99.9% by weight, based in each case on the weight of the respective composition. Preferably, the first water content and the second water content; or the first water content and the third water content; or the second water content and the third water content; or the first water content, the second water content and the third water content are in the aforementioned range.

In one embodiment 21 of the invention, the method 1 is configured according to any of its em bodiments 1 to 20, wherein the reducing of the first to third water contents is each effected in multiple steps, wherein the reducing of the first to third water contents each includes a first reduction step, wherein, in the first reduction step, the first to third water content, respectively, is reduced by at least 5% by weight, preferably by at least 10% by weight, more preferably by at least 15% by weight, most preferably by at least 18% by weight, based in each case on the weight of the respective composition. Preferably, between the first reduction step and a down stream, preferably subsequent, reduction step of reducing the first water content or the second water content or both, the first composition is superposed, preferably contacted, with the second composition. Alternatively or additionally preferably, between the first reduction step and a downstream, preferably subsequent, reduction step of reducing the second water content or the third water content or both, the second composition is superposed, preferably contacted, with the third composition. Preferably, between the first reduction step and a downstream, preferably subsequent, reduction step of reducing the first to third water content, the first composition is superposed, preferably contacted, with the second composition, and the second composition with the third composition. In the superposing, preferably in the contacting, the first to third compo sition, after the first reduction step, may in each case be in the form of a suspension or already be in the form of a sheetlike layer. It is also possible for one or two of the compositions to be in the form of a suspension and the other(s) to be in the form of a sheetlike layer. The suspension, with respect to the sheetlike layer, is characterised here especially by a pulpy consistency that allows the fibres in the suspension to freely change positions with one another. The latter can be regarded analogously to the mobility of molecules in a liquid by comparison with the fixed po sitions of molecules in a corresponding solid.

Additionally or alternatively to the above numerical values for reduction of the first to third water content in the first reduction step, the first to third water content in each case are reduced in the first reduction step to such an extent that a proportion of the first multitude of fibres in the first composition; a proportion of the second multitude of fibres in the second composition; and a proportion of the first multitude of fibres, or of the third multitude of fibres, or of the first and third multitude of fibres in total in the third composition is in each case increased to a value in the range from 3% to 35% by weight, preferably from 5% to 30% by weight, more preferably from 10% to 25% by weight, most preferably from 15% to 20% by weight, based on the total weight of the respective composition.

In one embodiment 22 of the invention, the method 1 is configured according to its embodiment 21, wherein the first reduction step of reducing the first to third water content in each case in cludes a first mechanical demoisturization. The first mechanical demoisturization is preferably effected by gravity. Additionally or alternatively, the first mechanical demoisturization prefera bly includes removal of water by suction. Especially preferably, the first reduction step of re ducing the first to third water content does not include pressing of solids of the respective com position.

In one embodiment 23 of the invention, the method 1 is configured according to its embodiment 21 or 22, wherein the reduction of the first to third water content in each case includes a second reduction step, wherein, in the second reduction step, the first to third water content is in each case reduced by at least 30% by weight, preferably by at least 35% by weight, more preferably by at least 40% by weight, even more preferably by at least 45% by weight, most preferably by at least 50% by weight, based in each case on the weight of the respective composition after the first reduction step and before the second reduction step. The second reduction step reduces the first to third water content preferably to values in a range from 30% to 75% by weight, more preferably from 35% to 70% by weight, most preferably from 40% to 60% by weight, based in each case on the weight of the respective composition. Preferably, the first to third composition are superposed on one another in the second reduction step; preferably, the first composition is contacted with the second composition and the second composition with the third composition. The first to third composition here are preferably in the form of a fibre structure. A particular feature of a fibre structure here is that the fibres are in joined form therein. What this means is more particularly that the fibres are no longer able to freely change positions in the structure, unlike in a suspension. Alternatively, in the second reduction step, the first to third sheetlike layer are superposed on one another; preferably, the first sheetlike layer is in contact with the second sheetlike layer, and the second sheetlike layer is in contact with the third sheetlike layer. In this case, the first to third water contents relate to the first to third sheetlike layers.

Additionally or alternatively to the above numerical values for reduction of the first to third water content in the second reduction step, the first to third water content in each case are re duced in the second reduction step to such an extent that a proportion of the first multitude of fibres in the first composition; a proportion of the second multitude of fibres in the second com position; and a proportion of the first multitude of fibres, or of the third multitude of fibres, or of the first and third multitude of fibres in total in the third composition is in each case increased to a value in the range from more than 25% up to 65% by weight, preferably from 30% to 60% by weight, more preferably from 35% to 55% by weight, most preferably from 40% to 50% by weight, based on the total weight of the respective composition.

In one embodiment 24 of the invention, the method 1 is configured according to its embodiment 23, wherein the second reduction step of reducing the first to third water content in each case includes a further mechanical demoisturization. The further mechanical demoisturization pref erably includes pressing of solids, especially fibres, of the respective composition which is pref erably in the form of a fibre structure.

In one embodiment 25 of the invention, the method 1 is configured according to any of its em bodiments 21 to 24, wherein the reduction of the first to third water content in each case includes a third reduction step, wherein, in the third reduction step, the first to third water content is in each case reduced by at least 80% by weight, preferably by at least 85% by weight, more pref erably by at least 90% by weight, even more preferably by at least 91% by weight, most prefer ably by at least 92% by weight, based in each case on the weight of the respective composition after the second reduction step and before the third reduction step. The third reduction step re duces the first to third water content preferably to values in a range from 1% to 20% by weight, more preferably from 2% to 15% by weight, most preferably from 4% to 9% by weight, based in each case on the weight of the respective composition.

In one embodiment 26 of the invention, the method 1 is configured according to its embodiment 25, wherein the third reduction step of reducing the first to third water content in each case includes a thermal treatment. A preferred thermal treatment includes heating to a temperature in a range from 30 to 120°C, more preferably from 40 to 110°C, more preferably from 50 to 105°C, most preferably from 55 to 100°C. Preferably, the thermal treatment comprises contacting the first composition or the third composition or each of them with a heated component which is preferably a rotating component, preferably a rotating roll. The heated component here is pref erably at a temperature in a range from 30 to 120°C, more preferably from 40 to 110°C, more preferably from 50 to 105°C, most preferably from 55 to 100°C. In the third reduction step, the first to third composition are preferably already in the form of the first to third sheetlike layer.

In one embodiment 27 of the invention, the method 1 is configured according to any of its em bodiments 1 to 25, wherein one selected from the group consisting of the fibres of the first mul titude of fibres, the fibres of the second multitude of fibres, and the fibres of the third multitude of fibres, or a combination of at least two of these, comprises and preferably consists of chemical pulp or a mechanical pulp or both. Preferably, the fibres of the first multitude of fibres comprise chemical pulp; more preferably, the fibres of the first multitude of fibres consist of chemical pulp. Alternatively or additionally preferably, the fibres of the first multitude of fibres do not include any mechanical pulp. The fibres of the second multitude of fibres preferably include chemical pulp or a mechanical pulp or both; more preferably, the fibres of the second multitude of fibres consist of chemical pulp or the mechanical pulp or of both. Preferably, the fibres of the third multitude of fibres comprise chemical pulp; more preferably, the fibres of the third multi tude of fibres consist of chemical pulp. Alternatively or additionally preferably, the fibres of the third multitude of fibres do not include any mechanical pulp. In one embodiment 28 of the invention, the method 1 is configured according to any of its em bodiments 8 to 26, wherein the crosslinking of the second sizing agent comprises reacting a first ester included in the second sizing agent to give a further ester different from the first ester.

In one embodiment 29 of the invention, the method 1 is configured according to any of its em bodiments 1 to 28, wherein one selected from the group consisting of the first composition, the second composition and the third composition, or a combination of at least two of these, in each case additionally includes an additive or a processing agent or both.

In one embodiment 30 of the invention, the method 1 is configured according to any of its em bodiments 1 to 29, wherein one selected from the group consisting of the fibres of the first mul titude of fibres, the fibres of the second multitude of fibres, and the fibres of the third multitude of fibres, or a combination of at least two of these, has at least one of the following properties:

A) an average fibre length in a range from 0.2 to 6 mm, preferably from 0.2 to 4.5 mm, more preferably from 0.5 to 4.0 mm, more preferably from 1.0 to 4.0 mm, even more preferably from 2.0 to 4.0 mm, most preferably from 3.0 to 4.0 mm,

B) a coarseness in a range from 50 to 400 pg/m, preferably from 100 to 300 pg/m, more preferably from 120 to 300 pg/m, even more preferably from 120 to 250 pg/m, most preferably from 130 to 200 pg/m,

C) an average wall thickness in a range from 2 to 10 pm, preferably from 3 to 9 pm, more preferably from 4 to 9 pm, more preferably from 5 to 8 pm, even more prefer ably from 6 to 8 pm, most preferably from 6 to 7 pm,

D) an average external diameter in a range from 10 to 50 pm, more preferably from 10 to 45 pm, more preferably from 20 to 45 pm, more preferably from 25 to 45 pm, more preferably from 30 to 45 pm, even more preferably from 30 to 40 pm, most preferably from 32 to 40 pm.

More preferably, the fibres of the first multitude of fibres, or the fibres of the third multitude of fibres, or both have the above property under point A). A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a carrier layer obtainable by the method 1 according to any of its embodiments 1 to 30.

In one embodiment 2 of the invention, the carrier layer is configured according to its embodi ment 1, wherein the carrier layer has a basis weight in a range from 120 to 450 g/m ² , preferably from 130 to 400 g/m ² , more preferably from 150 to 380 g/m ² .

In one embodiment 3 of the invention, the carrier layer is configured according to its embodi ment 1 or 2, wherein the carrier layer has a residual moisture content of less than 20% by weight, preferably in a range from 2% to 15% by weight, more preferably from 4% to 10% by weight, based in each case on the total weight of the carrier layer.

In one embodiment 4 of the invention, the carrier layer is configured according to any of its embodiments 1 to 3, wherein the carrier layer has a Scott bond value in a range from 100 to 360 J/m ² , preferably from 120 to 350 J/m ² , more preferably from 135 to 310 J/m ² .

In one embodiment 5 of the invention, the carrier layer is configured according to any of its embodiments 1 to 4, wherein the carrier layer has a first bending resistance in a first direction and a further bending resistance in a further direction at right angles to the first direction, wherein a ratio of the first bending resistance to the further bending resistance is in a range from 1 to 3.5, preferably from 1.2 to 3.0, more preferably from 1.5 to 2.8, even more preferably from 1.7 to 2.6, most preferably from 1.8 to 2.5. The first direction is preferably a machine direction (MD) of the production of the carrier layer by method 1. Thus, the fibres of the first to third multitude of fibres in the carrier layer are preferably oriented predominantly in the first direction. The further direction is preferably a cross direction (CD) of the production of the carrier layer by method 1.

In one embodiment 6 of the invention, the carrier layer is configured according to its embodi ment 5, wherein the first bending resistance is in a range from 50 to 800 mN, preferably from 50 to 500 mN, more preferably from 60 to 450 mN, more preferably from 70 to 400 mN, more preferably from 80 to 350 mN, even more preferably from 100 to 350 mN, most preferably from 120 to 350 mN. Alternatively preferably, the first bending resistance is in a range from 50 to 400 mN, preferably from 50 to 300 mN, more preferably from 50 to 200 mN, more preferably from 60 to 180 mN, more preferably from 70 to 170 mN, most preferably from 70 to 100 mN.

In one embodiment 7 of the invention, the carrier layer is configured according to its embodi ment 5 or 6, wherein the further bending resistance is in a range from 20 to 400 mN, preferably from 20 to 300 mN, more preferably from 20 to 250 mN, more preferably from 20 to 200 mN, more preferably from 20 to 180 mN, more preferably from 20 to 160 mN, even more preferably from 40 to 160 mN, most preferably from 60 to 160 mN. Alternatively preferably, the further bending resistance is in a range from 20 to 150 mN, preferably from 20 to 120 mN, most pref erably from 20 to 100 mN.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a sheetlike composite 1 comprising, as mutually superposed layers, in a direc tion from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) the carrier layer according to any of its embodiments 1 to 7,

b) a barrier layer, and

c) an inner polymer layer.

The sheetlike composite is preferably obtainable by method 2 according to the invention.

In one embodiment 2 of the invention, the sheetlike composite 1 is configured according to its embodiment 1, wherein the third sheetlike layer in the sheetlike composite faces the inner face of the sheetlike composite. In this connection, more preferably, the first average fibre length is less than the third average fibre length, preferably by 0.1 to 3 mm, more preferably by 0.5 to 2.5 mm, most preferably by 1 to 2.0 mm.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a method 2 comprising, as method steps, a. providing the carrier layer according to any of its embodiments 1 to 7, or a sheetlike composite precursor comprising the carrier layer according to any of its embodiments 1 to 7;

b. superposing the carrier layer on a first layer side of the carrier layer with a barrier layer, and

c. superposing the barrier layer on a side of the barrier layer remote from the carrier layer with an inner polymer layer thereby obtaining a sheetlike composite.

The method 2 is preferably a method of producing the sheetlike composite.

In one embodiment 2 of the invention, the method 2 is configured according to its embodiment 1, wherein the method comprises, between method steps a. and b., covering of the carrier layer with an outer polymer layer on a further layer side of the carrier layer. Preferably, the first layer side and the further layer side of the carrier layer are opposite one another.

In one embodiment 3 of the invention, the method 2 is configured according to its embodiment 1 or 2, wherein, in method step b., a polymer interlayer is introduced between the carrier layer and the barrier layer.

In one embodiment 4 of the invention, the method 2 is configured according to any of its em bodiments 1 to 3, wherein the method additionally comprises a method step of

d. superposing of the carrier layer with an ink application on a further layer side of the carrier layer.

Preferably, the ink application in method step d. is applied to the outer polymer layer or directly to the carrier layer, preferably printed on. Preferably, the first layer side and the further layer side of the carrier layer are opposite one another.

In one embodiment 5 of the invention, the method 2 is configured according to any of its em bodiments 1 to 4, wherein the method additionally includes, after method step c., cutting of the sheetlike composite to size thereby forming a blank for production of a single, preferably closed, container. Preferably, the cutting-to-size is effected after method step d. In one embodiment 6 of the invention, the method 2 is configured according to any of its em bodiments 1 to 5, wherein the method comprises, between method steps a. and b., superposing of the carrier layer with an ink application on a further layer side of the carrier layer. Preferably, the ink application is applied to the outer polymer layer or directly to the carrier layer, preferably printed on. Preferably, the first layer side and the further layer side of the carrier layer are oppo site one another.

In one embodiment 7 of the invention, the method 2 is configured according to any of its em- bodiments 1 to 6, wherein the third sheetlike layer in the carrier layer, based on the second sheetlike layer, is arranged facing the first layer side. Alternatively or additionally preferably, the first sheetlike layer in the carrier layer, based on the second sheetlike layer, faces the further layer side. A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a sheetlike composite 2 obtainable by the method 2 according to any of its embodiments 1 to 7.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a container precursor including the carrier layer according to any of its embod iments 1 to 7, or the sheetlike composite 1 or 2, in each case according to any of its embodiments.

In one embodiment 2 of the invention, the container precursor is configured according to its embodiment 1, wherein the carrier layer or the sheetlike composite comprises at least two folds.

In one embodiment 3 of the invention, the container precursor is configured according to its embodiment 1 or 2, wherein the carrier layer or the sheetlike composite comprises a first longi tudinal edge and a further longitudinal edge, wherein the first longitudinal edge is joined to the further longitudinal edge to form a longitudinal seam of the container precursor. A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a container including the carrier layer according to any of its embodiments 1 to 7, or the sheetlike composite 1 or 2, in each case according to any of its embodiments. A preferred container is a closed container.

In one embodiment 2 of the invention, the container is configured according to its embodiment 1, wherein the container comprises a food or drink product.

In one embodiment 3 of the invention, the container is configured according to its embodiment 1 or 2, wherein the carrier layer or the sheetlike composite comprises a first longitudinal edge and a further longitudinal edge, wherein the first longitudinal edge is joined to the further longi tudinal edge to form a longitudinal seam of the container.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a use 1 of the carrier layer according to any of its embodiments 1 to 7, or of the sheetlike composite 1 or 2, for production of a food or drink product container.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a use 2 of

a) a first composition having a first pH, said first composition including

i) water in a first water content,

ii) a first multitude of fibres, and

iii) a first sizing agent,

b) a second composition having a second pH, said second composition including

i) water in a second water content,

ii) a second multitude of fibres, and

iii) a second sizing agent, and

c) a third composition having a third pH, said third composition including

i) water in a third water content, ii) a third multitude of fibres, and

iii) the first sizing agent or a third sizing agent or both,

for production of a cardboard, paperboard or paper layer comprising a layer sequence compris ing, as mutually superposed layers in this sequence,

a. a first sheetlike layer obtainable from the first composition,

b. a second sheetlike layer obtainable from the second composition, and

c. a third sheetlike layer obtainable from the third composition;

wherein the first pH or the third pH or each of them is lower than the second pH. Preferably, the first and second sizing agent, or the first to third sizing agent, are used for internal sizing of the cardboard, paperboard or paper layer. In the context of the use 2, the features of the first to third composition and of their respective constituents that are taught as being preferred for method 1 are likewise preferred.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a use 3 of rosin as the first sizing agent or the third sizing agent or both in the method 1 according to any of its embodiments 1 to 30.

A contribution to the achievement of at least one of the objects of the invention is made by an embodiment 1 of a use 4 of an alkyl ketene dimer or of an alkenylsuccinic anhydride or of a mixture of the two as the second sizing agent in the method 1 according to any of its embodi ments 1 to 30. A preferred alkyl ketene dimer is also abbreviated to AKD in papermaking. A preferred alkenylsuccinic anhydride is also abbreviated to ASA in papermaking.

Features described as preferred in one category of the invention, for example according to the method 1, are likewise preferred in an embodiment of the further categories of the invention.

First to third composition

Useful first to third compositions are any compositions that seem suitable to the person skilled in the art for the use of the invention and are especially known from paper, cardboard or paper- board production. The compositions are preferably in the form of a suspension in method step a). Preferably, the first to third compositions are pulps. As well as water, fibres and sizing agents, the compositions may include further ingredients, for example additives or processing agents or both. Preferred additives are selected from the group consisting of a filler, a dry paper strength- ener, a wet paper strengthener, and a colorant, or a combination of at least two of these. Preferred processing agents are selected from the group consisting of a retention agent, a fixative, a floc- culant, a defoamer, a deaerator, a slimicide and a biocide, or a combination of at least two of these.

Fibres

Useful fibres are any fibres that seem suitable to the person skilled in the art for the use of the invention, especially all fibres known in paper, cardboard or paperboard production. Fibres are linear elongate structures that have a ratio of length to diameter or thickness of at least 3 : 1. For some fibres, the aforementioned ratio is not greater than 100: 1. For use in this document, long fibres have an average fibre length in a range from 3 to 4 mm and short fibres have an average fibre length in a range from 0.4 to 2 mm.

Preferred fibres are plant fibres. Plant fibres is a collective term for fibres of plant origin, i.e. fibres obtained from plants. In plants, plant fibres occur as a vascular bundle in the stalk or stem, in the bark (for instance in the form of bast) and as seed shoots. A subdivision is made in DIN 60001-1 : 2001-05 Textile fibres - Part 1 :“Natural fibres and letter codes”, Beuth Verlag, Berlin 2001, p. 2 into seed fibres, bast fibres and hard fibres, and in DIN EN ISO 6938: 2015-01“Tex tiles - Natural fibres - Generic names and definitions”, Beuth Verlag, Berlin 2015, p. 4 into seed fibres, bast fibres, leaf fibres and fruit fibres, which thus implements a division of the hard fibres. Plant fibres that are preferred in the context of the invention are predominantly manufactured from the wood from trees. A preferred wood here is a softwood, i.e. a wood from a conifer tree, or a hardwood, i.e. a wood from a deciduous tree. In the case of softwood, preference is given to tracheids. In the case of hardwood, preference is given to libriforms.

Fibres that are preferred in the context of the invention include chemical pulp or a mechanical pulp or both; the fibres preferably consist thereof. A preferred mechanical pulp is one selected from the group consisting of ground wood, pressure-ground wood and a thermomechanical pulp (TMP), or a combination of at least two of these. A preferred thermomechanical pulp is a che- mithermomechanical pulp (CTMP). Mechanical pulp is notable here for a greater proportion of lignin compared to chemical pulp, which can be detected by means of red staining with phloroglucinol solution. Fibres that are preferred in the context of the invention have been ob tained from the wood from a tree selected from the group consisting of spruce, pine, birch, and eucalyptus, or a combination of at least two of these.

Sizing agent

In the technical field of paper, paperboard and cardboard production, the person skilled in the art understands sizing to mean the reduction of the hydrophilic properties of paper, paperboard or cardboard in order to make the material printable with aqueous or solventborne printing inks. The person skilled in the art distinguishes between surface sizing (thin application of sizing agent on the top side of a material web or a sheet) and internal sizing. In internal sizing, at least one sizing agent is added to the fibre mass prior to sheet formation. In the context of the invention, useful sizing agents are all sizing agents that seem suitable to the person skilled in the art for the use of the invention, particular preference being given to sizing agents for internal sizing. Sizing agents are preferably hydrophobizing polymers. A preferred sizing agent is a copolymer of sty rene and acrylic esters, or of styrene and maleic acid; a resin; or an ester. A preferred ester is an alkyl ketene dimer or an alkenylsuccinic anhydride or a mixture of the two. A preferred alkyl ketene dimer is also abbreviated to AKD in papermaking. A preferred alkenylsuccinic anhydride is also abbreviated to ASA in papermaking. AKD here has the structural formula:

In the oxetane ring of preferred alkyl ketene dimers, there is a Cn- to Ci ₆ -alkyl group in the 3 position and a C ₁₃ - to Cn-alkylidene group in the 4 position. AKD can typically be used without addition of aluminium sulfate. Suitable AKD can be obtained from naturally occurring products. Suitable starting materials are vegetable or animal fats and oils (e.g. palm kernel oil), from which the higher fatty acids (palmitic acid or stearic acid) can be isolated by fat hydrolysis. For prepa ration of the suitable AKD, these can be converted to the corresponding acid chlorides (alkyl- CH2-CO-CI), from which the AKD is formed in the presence of an amine by dehydrohalogena- tion (elimination of HC1) and simultaneous dimerization of the ketene formed as an intermediate (alkyl-CH=C=0).

ASA, moreover, has the structural formula:

A preferred alkenylsuccinic anhydride bears, in the 2 position, a long-chain (preferably C ₁₄ - to C22-) branched /.voalkene radical.

Sizing with a sizing agent

In general, in the context of the invention, sizing of fibres with a sizing agent is understood to mean fixing of the sizing agent on the fibres. For this purpose, van der Waals binding forces between the fibres and the sizing agent are preferably increased. The sizing, especially in the case of the second sizing agent, is preferably effected in the form of a crosslinking operation, i.e. a chemical reaction. The crosslinking preferably comprises esterifying the sizing agent. A preferred mode of crosslinking the second sizing agent comprises chemically reacting a first ester included in the second sizing agent to give a further ester different from the first ester.

Resin Useful resins include all resins and resin sizes that are known to the person skilled in the art and seem suitable for the purpose of the invention. A preferred resin is a natural resin, a chemically modified natural resin, or a synthetic resin or a mixture of at least two of the above. A preferred resin size is a natural resin size, a chemically modified natural resin, or a synthetic resin or a mixture of at least two of the above.

Natural resins are secreted by animals and plants, especially trees. They serve primarily to seal wounds of the plant. Traditionally, resins are yellowish to brownish, clear to cloudy, tacky and noncrystalline materials of natural origin that are soluble in the standard organic solvents, but not in water. In general, natural resin is a collective term for mixtures of different chemical substances that each include resin acids, which are among the carboxylic acids. A preferred natural resin is one selected from the group consisting of turpentine, balsam, gum lac, rosin, sandarac and mastic, or a combination of at least two of these. Particular preference is given here to rosin. All the aforementioned natural resins may also be produced synthetically. A resin par ticularly preferred in accordance with the invention is a chemically modified rosin. A preferred mode of chemical modification of a natural resin in the production of suitable resin size com prises modifying resin acids, which preferably comprises strengthening or at least partly esteri- fying or both. Further preferably, the strengthening comprises increasing a number of carboxyl groups by a reaction with maleic anhydride or fumaric acid or with both. The strengthening preferably reduces a tendency of tall resins to crystallize on hydrolysis, increases the stability of the dispersions and enhances the adhesion of the resin particles in the fibrous material, which ultimately leads to an increased sizing effect.

According to ISO 4618:2014(de) (“Coating materials— Terms and definitions”), synthetic res ins are resins manufactured synthetically by polymerization-, polyaddition- or polycondensa tion-reaction. According to the IUPAC conventions, they are soft solids or highly viscous sub stances usually containing prepolymers with reactive functional groups (entry for“resin” in “IUPAC Compendium of Chemical Terminology” (the “Gold Book”), doi: 10.1351/goldbook.RT07166, Version 2.3.3). On processing, synthetic resins generally con sist of two main components. The mixing of the two portions (resin and curing agent) results in a reactive resin mass. The viscosity rises on curing and, on completion of curing, an unmeltable plastic (thermoset) is obtained. Synthetic resins may be modified by natural substances, for ex ample vegetable or animal oils or natural resins, as, for example, in the case of alkyd resins. However, synthetic resins also refer to natural resins that have been modified by esterification or hydrolysis. A preferred synthetic resin is one selected from the group consisting of a phenolic resin, an aminoplast, an epoxy resin, a polyester resin and an ABS resin, or a combination of at least two of these. Phenolic resins are obtainable here by polycondensation of formaldehyde and phenol. Preferred aminoplasts are urea-formaldehyde (UF resin) or melamine-formaldehyde (MF resin) or both. Urea-formaldehyde is obtainable by polycondensation of formaldehyde with urea. Melamine-formaldehyde is obtainable by polycondensation of formaldehyde with mela mine. Epoxy resins are obtainable by polyaddition or polycondensation or both from polyhydric phenols and epichlorohydrin. Polyester resins (UP resins) are obtainable on the basis of unsatu rated polyesters. ABS resins are mixtures of at least one resin with an elastomer. Base monomers here include acrylonitrile, 1,3-butadiene and styrene. Synthetic resins are generally liquid or solid amorphous products having no sharp boiling point or melting point. For industrial use, the synthetic resins are often obtainable in the form of an emulsion or suspension, or are produced in this form. Many of these synthetic resins are also usable in principle as true solutions, but since the solvents that are usually needed for the purpose are volatile organic compounds, this proportion is becoming ever lower. The synthetic resins include, for example, condensation res ins and reactive resins.

Following the IUPAC recommendations, the term“resin” is not generally equated with polymers herein. Accordingly, for example, polyethylene is not a resin, even though some specialists use the term“polyethylene resin”.

Sheetlike layer

Suitable first to third sheetlike layers in the context of the invention are all sheetlike layers that seem suitable to the person skilled in the art and are obtainable by the method according to the invention. In this case, an extent of the sheetlike layer in a layer plane, i.e. its length and width, is always distinctly greater, preferably by a factor of at least 100, more preferably at least 1000, than a thickness of the sheetlike layer at right angles to the layer plane. A preferred sheetlike layer is a ply of cardboard. The first to third sheetlike layers are preferably compressed together (couched) to obtain the carrier layer. In addition, one or more of the sheetlike layers to be bonded to one another, prior to the compression, can be superposed, preferably sprayed, with a bonding agent, especially a starch. Preferably, no glue is used for this purpose. Accordingly, method step b) of method 1 of the invention preferably includes pressing of the first sheetlike layer with the second sheetlike layer and of the second sheetlike layer with the third sheetlike layer. The carrier layer of the invention, preferably obtainable by method 1, may, in addition to the first to third sheetlike layer, include further layers, for example paper coating layers or further plies of card board.

Carrier layer

The carrier layer used may be any material which seems suitable for a person skilled in the art for this purpose and which has sufficient strength and stiffness to impart stability to a container obtained from a sheetlike composite with the carrier layer to such an extent that the container in the filled state essentially retains its shape. Accordingly, containers in the context of the inven tion are dimensionally stable and hence should fundamentally be distinguished from pouches and bags that are typically manufactured from thin films. As well as a number of plastics, pref erence is given to plant-based fibrous materials, especially mechanical pulps and chemical pulps, preferably sized, bleached and/or unbleached mechanical pulps and chemical pulps, for for mation of the carrier layer. A preferred carrier layer is a paper, paperboard or cardboard layer, particular preference being given to a cardboard layer. Accordingly, a preferred carrier layer comprises a multitude of fibres. The basis weight of the carrier layer is preferably in a range from 120 to 450 g/m ² , especially preferably in a range from 130 to 400 g/m ² and most preferably in a range from 150 to 380 g/m ² .

The carrier layer has at least the first to third sheetlike layer, but may also include further layers between two of the aforementioned layers or layers that superpose the layer sequence composed of first to third sheetlike layer. For example, the layer sequence composed of first to third sheet like layer may be coated on one or both sides by one or else more than one cover layer. In addition, a preferred carrier layer has a residual moisture content of less than 20% by weight, preferably of 2% to 15% by weight and especially preferably of 4% to 10% by weight, based on the total weight of the carrier layer. Further preferably, the carrier layer, especially in the case of a cardboard layer, on the surface facing the outer face in the sheetlike composite, has at least one lamina, but more preferably at least two laminas, of a cover layer known to the person skilled in the art as a“paper coating”. In addition, a preferred carrier layer, especially a cardboard layer, has a Scott bond value (according to Tappi T403um) in a range from 100 to 360 J/m ² , preferably from 120 to 350 J/m ² and especially preferably from 135 to 310 J/m ² . By virtue of the aforemen tioned ranges, it is possible to provide a sheetlike composite with the carrier layer from which it is possible to fold a container with high integrity, easily and in low tolerances.

The carrier layer preferably has a bending resistance in a first direction in a range from 50 to 800 mN. The first direction is preferably an orientation direction of fibres selected from the group consisting of the fibres in the first sheetlike layer, the fibres in the second sheetlike layer, and the fibres in the third sheetlike layer, or a combination of at least two of these. More prefer ably, the first direction is an orientation direction of all fibres in the carrier layer. Preferably, the carrier layer has a bending resistance in a second direction at right angles to the first direction in a range from 20 to 400 mN. A preferred sheetlike composite with the carrier layer has a bending resistance in the first direction in a range from 80 to 900 mN. Further preferably, the aforemen tioned sheetlike composite has a bending resistance in the second direction in a range from 20 to 500 mN.

Cover layer

A preferred outer layer is a "paper coating". A "paper coating" in papermaking is a cover layer comprising inorganic solid particles, preferably pigments and additives. The "paper coating" is preferably applied as a liquid phase, preferably as a suspension or dispersion, to a surface of a paper- or cardboard-containing layer. A preferred dispersion is an aqueous dispersion. A pre ferred suspension is an aqueous suspension. A further preferred liquid phase comprises inorganic solid particles, preferably pigments; a binder; and additives. A preferred pigment is selected from the group consisting of calcium carbonate, kaolin, talc, silicate, a plastic pigment and titanium dioxide. A preferred kaolin is a calcined kaolin. A preferred calcium carbonate is one selected from the group consisting of marble, chalk, and a precipitated calcium carbonate (PCC), or a combination of at least two thereof. A preferred silicate is a sheet silicate. A preferred plastic pigment is spherical, preferably hollow spherical. A preferred binder is one selected from the group consisting of styrene-butadiene, acrylate, acrylonitrile, a starch and a polyvinyl alcohol or a combination of at least two thereof, preference being given to acrylate. A preferred starch is one selected from the group consisting of cationically modified, anionically modified and frag mented starch or a combination of at least two thereof. A preferred additive is one selected from the group consisting of a rheology modifier, a tinting dye, an optical brightener, a carrier for an optical brightener, a flocculating agent, a deaerator, and a surface energy modifier, or a combi nation of at least two thereof. A preferred deaerator is an emulsion paint deaerator, preferably based on silicone or based on fatty acids or both. A preferred surface energy modifier is a sur factant.

Lavers

Two layers of the carrier layer or else of the sheetlike composite are joined to one another when their bonding to one another extends beyond van der Waals attraction forces. Layers that have been bonded to one another preferably belong to a category selected from the group consisting of sealed to one another, adhesively bonded to one another, and compressed to one another, or a combination of at least two of these. In the case of layers of the carrier layer, especially of the first to third sheetlike layer, these are preferably compressed together, but not sealed or adhe sively bonded to one another. Unless stated otherwise, in a layer sequence, the layers may follow one another indirectly, i.e. with one or at least two intermediate layers, or directly, i.e. with no intermediate layer. This is the case especially in the form of words in which one layer superposes another layer. A form of words in which a layer sequence comprises enumerated layers means that at least the layers specified are present in the sequence specified. This form of words does not necessarily mean that these layers follow on directly from one another. A form of words in which two layers adjoin one another means that these two layers follow on from one another directly and hence with no intermediate layer. However, this form of words does not say anything as to whether or not the two layers have been joined to one another. Instead, these two layers may be in contact with one another.

Sheetlike composite

Useful sheetlike composites include all sheetlike composite materials that are conceivable within the context of the invention and seem suitable to the person skilled in the art for the use of the invention for production of food and drink product containers. Sheetlike composites for produc tion of food or drink product containers are also referred to as laminates. Sheetlike composites of this kind are frequently constructed from a thermoplastic polymer layer, a carrier layer usually consisting of cardboard or paper which endows the container with its dimensional stability, an adhesion promoter layer, a barrier layer and a further thermoplastic polymer layer, as disclosed inter alia in WO 90/09926 A2.

Polymer layers

The term "polymer layer" refers hereinafter especially to the inner polymer layer, the polymer interlayer and the outer polymer layer. A preferred polymer layer has a polymer content of at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, even more preferably at least 95% by weight, most preferably at least 99% by weight, based in each case on the weight of the polymer layer. The polymer content may refer here to a single polymer or a mixture of multiple polymers, for example to a blend. A preferred polymer is a thermoplastic polymer, more preferably a polyolefin. The polymer layers may have further constituents. The polymer layers are preferably introduced into or applied to the sheetlike com posite material in an extrusion method. The further constituents of the polymer layers are pref erably constituents that do not adversely affect the behaviour of the polymer melt on application as a layer. The further constituents may, for example, be inorganic compounds, such as metal salts, or further polymers, such as further thermoplastics. However, it is also conceivable that the further constituents are fillers or pigments, for example carbon black or metal oxides. Suita ble thermoplastics for the further constituents especially include those that are readily processi- ble by virtue of good extrusion characteristics. Among these, polymers obtained by chain polymerization are suitable, especially polyesters or polyolefins, particular preference being given to cyclic olefin copolymers (COCs), polycyclic olefin copolymers (POCs), especially pol yethylene and polypropylene, and very particular preference to polyethylene. Among the poly- ethylenes, preference is given to HDPE {high density polyethylene ), MDPE {medium density polyethylene ), LDPE {low density polyethylene ), LLDPE {linear low density polyethylene) and VLDPE {very low density polyethylene ) and mixtures of at least two of these. It is also possible to use mixtures of at least two thermoplastics. Suitable polymer layers have a melt flow rate (MFR) in a range from 1 to 25 g/10 min, preferably in a range from 2 to 20 g/10 min and more preferably in a range from 2.5 to 15 g/10 min, and a density in a range from 0.890 g/cm ³ to 0.980 g/cm ³ , preferably in a range from 0.895 g/cm ³ to 0.975 g/cm ³ , and further preferably in a range from 0.900 g/cm ³ to 0.970 g/cm ³ . The polymer layers preferably have at least one melting temperature in a range from 80 to 155°C, preferably in a range from 90 to 145°C and more preferably in a range from 95 to 135°C.

Inner polymer layer

The inner polymer layer is preferably based on thermoplastic polymers, where the inner polymer layer may include a particulate inorganic solid. However, it is preferable that the inner polymer layer comprises one or more thermoplastic polymers to an extent of at least 70% by weight, preferably at least 80% by weight and particularly preferable at least 95% by weight, based in each case on the total weight of the inner polymer layer. Preferably, the polymer or polymer mixture of the inner polymer layer has a density (to ISO 1183-1 :2004) in a range from 0.900 to 0.980 g/cm ³ , particularly preferable in a range from 0.900 to 0.960 g/cm ³ and most preferably in a range from 0.900 to 0.940 g/cm ³ . The polymer is preferably a polyolefin, mPolymer or a combination of the two. The inner polymer layer preferably comprises a polyethylene or a pol ypropylene or both. In this context, a particularly preferred polyethylene is an LDPE. Preferably, the inner polymer layer includes the polyethylene, polypropylene or both together in a proportion of at least 30% by weight, more preferably at least 40% by weight, most preferably at least 50% by weight, based in each case on the total weight of the inner polymer layer. Additionally or alternatively, the inner polymer layer preferably includes an HDPE, preferably in a proportion of at least 5% by weight, more preferably at least 10% by weight, more preferably at least 15% by weight, most preferably at least 20% by weight, based in each case on the total weight of the inner polymer layer. Additionally or alternatively to one or more of the aforementioned poly mers, the inner polymer layer preferably includes a polymer prepared by means of a metallocene catalyst, preferably an mPE. Preferably, the inner polymer layer includes the mPE in a propor tion of at least 3% by weight, more preferably at least 5% by weight, based in each case on the total weight of the inner polymer layer. In this case, the inner polymer layer may include 2 or more, preferably 2 or 3, of the aforementioned polymers in a polymer blend, for example at least a portion of the LDPE and the mPE, or at least a portion of the LDPE and the HDPE. In addition, the inner polymer layer may include 2 or more, preferably 3, mutually superposed sublayers which preferably form the inner polymer layer. These sublayers are preferably layers obtained by coextrusion.

In a preferred configuration of the sheetlike composite, the inner polymer layer includes, in a direction from the outer face of the sheetlike composite to the inner face of the sheetlike com posite, a first sublayer including an LDPE in a proportion of at least 50% by weight, preferably of at least 60% by weight, more preferably of at least 70% by weight, even more preferably of at least 80% by weight, most preferably of at least 90% by weight, based in each case on the weight of the first sublayer; and a further sublayer including a blend, wherein the blend includes an LDPE in a proportion of at least 30% by weight, preferably of at least 40% by weight, more preferably of at least 50% by weight, even more preferably of at least 60% by weight, most preferably of at least 65% by weight, and an mPE in a proportion of at least 10% by weight, preferably of at least 15% by weight, more preferably of at least 20% by weight, most preferably of at least 25% by weight, based in each case on the weight of the blend. In this case, the further sublayer includes the blend preferably in a proportion of at least 50% by weight, preferably of at least 60% by weight, more preferably of at least 70% by weight, even more preferably of at least 80% by weight, most preferably of at least 90% by weight, based in each case on the weight of the further sublayer. More preferably, the further sublayer consists of the blend.

In a further preferred configuration of the sheetlike composite, the inner polymer layer includes, in a direction from the outer face of the sheetlike composite to the inner face of the sheetlike composite, a first sublayer including an HDPE in a proportion of at least 30% by weight, preferably of at least 40% by weight, more preferably of at least 50% by weight, even more preferably of at least 60% by weight, most preferably of at least 70% by weight, and an LDPE in a proportion of at least 10% by weight, preferably of at least 15% by weight, more preferably of at least 20% by weight, based in each case on the weight of the first sublayer; a second sub layer including an LDPE in a proportion of at least 50% by weight, preferably of at least 60% by weight, more preferably of at least 70% by weight, even more preferably of at least 80% by weight, most preferably of at least 90% by weight, based in each case on the weight of the second sublayer; and a third sublayer including a blend, wherein the blend includes an LDPE in a pro portion of at least 30% by weight, preferably of at least 40% by weight, more preferably of at least 50% by weight, even more preferably of at least 60% by weight, most preferably of at least 65% by weight, and an mPE in a proportion of at least 10% by weight, preferably of at least 15% by weight, more preferably of at least 20% by weight, most preferably of at least 25% by weight, based in each case on the weight of the blend. In this case, the third sublayer includes the blend preferably in a proportion of at least 50% by weight, preferably of at least 60% by weight, more preferably of at least 70% by weight, even more preferably of at least 80% by weight, most preferably of at least 90% by weight, based in each case on the weight of the third sublayer. More preferably, the third sublayer consists of the blend.

Outer polymer layer

The outer polymer layer preferably comprises a polyethylene or a polypropylene or both. Pre ferred polyethylenes here are LDPE and HDPE and mixtures of these. A preferred outer polymer layer comprises an LDPE to an extent of at least 50% by weight, preferably to an extent of at least 60% by weight, more preferably to an extent of at least 70% by weight, still more preferably to an extent of at least 80% by weight, most preferably to an extent of at least 90% by weight, based in each case on the weight of the outer polymer layer.

Polymer interlayer

The polymer interlayer preferably comprises a polyethylene or a polypropylene or both. In this context, a particularly preferred polyethylene is an LDPE. Preferably, the polymer interlayer includes the polyethylene or the polypropylene or both together in a proportion of at least 20% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, most preferably at least 90% by weight, based in each case on the total weight of the polymer interlayer. Additionally or alterna tively, the polymer interlayer preferably includes an HDPE, preferably in a proportion of at least 10% by weight, more preferably at least 20% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, most preferably at least 90% by weight, based in each case on the total weight of the polymer interlayer. In this context, the polymer interlayer includes the aforementioned polymers preferably in a polymer blend.

Barrier layer

The barrier layer used may be any material which is suitable for a person skilled in the art for this purpose and which has sufficient barrier action, especially with respect to oxygen. The bar rier layer is preferably selected from a. a polymer barrier layer;

b. a metal layer;

c. a metal oxide layer; or

d. a combination of at least two of a. to c.

If the barrier layer, according to alternative a., is a polymer barrier layer, this preferably com prises at least 70% by weight, especially preferably at least 80% by weight and most preferably at least 95% by weight of at least one polymer which is known to the person skilled in the art for this purpose, especially for aroma or gas barrier properties suitable for packaging containers. Useful polymers, especially thermoplastics, here include N- or O-bearing polymers, either alone or in mixtures of two or more. According to the invention, it may be found to be advantageous when the polymer barrier layer has a melting temperature in a range from more than 155 to 300°C, preferably in a range from 160 to 280°C and especially preferably in a range from 170 to 270°C.

Further preferably, the polymer barrier layer has a basis weight in a range from 2 to 120 g/m ² , preferably in a range from 3 to 60 g/m ² , especially preferably in a range from 4 to 40 g/m ² and further preferably from 6 to 30 g/m ² . Further preferably, the polymer barrier layer is obtainable from melts, for example by extrusion, especially laminar extrusion. Further preferably, the pol ymer barrier layer may also be introduced into the sheetlike composite via lamination. It is pref erable in this context that a film is incorporated into the sheetlike composite. In another embod iment, it is also possible to select polymer barrier layers obtainable by deposition from a solution or dispersion of polymers.

Suitable polymers preferably include those having a weight-average molecular weight, deter mined by gel permeation chromatography (GPC) by means of light scattering, in a range from 3 10 ³ to 1 · 10 ⁷ g/mol, preferably in a range from 5 · 10 ³ to 1 · 10 ⁶ g/mol and especially preferably in a range from 6 · 10 ³ to 1 · 10 ⁵ g/mol. Suitable polymers especially include polyamide (PA) or polyethylene vinyl alcohol (EVOH) or a mixture thereof.

Among the polyamides, useful PAs are all of those that seem suitable to the person skilled in the art for the use according to the invention. Particular mention should be made here of PA 6, PA 6.6, PA 6.10, PA 6.12, PA 11 or PA 12 or a mixture of at least two of these, particular preference being given to PA 6 and PA 6.6 and further preference to PA 6. PA 6 is commercially available, for example, under the Akulon ^® , Durethan ^® and Ultramid ^® trade names. Additionally suitable are amorphous polyamides, for example MXD6, Grivory ^® and Selar ^® PA. It is further preferable that the PA has a density in a range from 1.01 to 1.40 g/cm ³ , preferably in a range from 1.05 to 1.30 g/cm ³ and especially preferably in a range from 1.08 to 1.25 g/cm ³ . It is further preferable that the PA has a viscosity number in a range from 130 to 250 ml/g and preferably in a range from 140 to 220 ml/g. Useful EVOHs include all the EVOHs that seem suitable to the person skilled in the art for the use according to the invention. Examples of these are commercially available, inter alia, under the EVAL™ trade names from EVAL Europe NV, Belgium, in a multitude of different versions, for example the EVAL™ F104B or EVAL™ LR171B types. Preferred EVOHs have at least one, two, more than two or all of the following properties:

an ethylene content in a range from 20 to 60 mol%, preferably from 25 to 45 mol%; a density in a range from 1.0 to 1.4 g/cm ³ , preferably from 1.1 to 1.3 g/cm ³ ;

a melting point in a range from more than 155 to 235°C, preferably from 165 to 225°C; - an MFR value (210°C/2.16 kg when T _S( EVOH) < 230°C; 230°C/2.16 kg when 210°C < TS(EVOH) < 230°C) in a range from 1 to 25 g/10 min, preferably from 2 to 20 g/10 min; an oxygen permeation rate in a range from 0.05 to 3.2 cm ³ -20 pm/(m ² dayatm), prefer ably in a range from 0.1 to 1 cm ³ -20 pm/(m ² dayatm).

Preferably at least one polymer layer, further preferably the inner polymer layer, or preferably all polymer layers, has/have a melting temperature below the melting temperature of the barrier layer. This is especially true when the barrier layer is formed from polymer. The melting tem peratures of the at least one polymer layer, especially the inner polymer layer, and the melting temperature of the barrier layer preferably differ here by at least 1 K, especially preferably by at least 10 K, still more preferably by at least 50 K, even more preferably by at least 100 K. The temperature difference should preferably be chosen to be only of such an amount that there is no melting of the barrier layer, especially no melting of the polymer barrier layer, during the folding.

According to alternative b., the barrier layer is a metal layer. Suitable metal layers are in principle all layers comprising metals which are known to the person skilled in the art and which can provide high light opacity and oxygen impermeability. In a preferred embodiment, the metal layer may take the form of a foil or a deposited layer, for example after a physical gas phase deposition. The metal layer is preferably an uninterrupted layer. In a further preferred embodi ment, the metal layer has a thickness in a range from 3 to 20 pm, preferably in a range from 3.5 to 12 pm and especially preferably in a range from 4 to 10 pm. Metals selected with preference are aluminium, iron or copper. A preferred iron layer may be a steel layer, for example in the form of a foil. Further preferably, the metal layer is a layer com prising aluminium. The aluminium layer may appropriately consist of an aluminium alloy, for example AlFeMn, AlFel .5Mn, AlFeSi or AlFeSiMn. The purity is typically 97.5% or higher, preferably 98.5% or higher, based in each case on the overall aluminium layer. In a particular configuration, the metal layer consists of an aluminium foil. Suitable aluminium foils have a ductility of more than 1%, preferably of more than 1.3% and especially preferably of more than 1.5%, and a tensile strength of more than 30 N/mm ² , preferably more than 40 N/mm ² and espe cially preferably more than 50 N/mm ² . Suitable aluminium foils exhibit in the pipette test a droplet size of more than 3 mm, preferably more than 4 mm and especially preferably of more than 5 mm. Suitable alloys for producing aluminium layers or foils are commercially available under the designations EN AW 1200, EN AW 8079 or EN AW 8111 from Hydro Aluminium Deutschland GmbH or Amcor Flexibles Singen GmbH. In the case of a metal foil as a barrier layer, it is possible to provide an adhesion promoter layer between the metal foil and a closest polymer layer on one and/or both sides of the metal foil.

Further preferably, the barrier layer selected, according to alternative c., may be a metal oxide layer. Useful metal oxide layers include all metal oxide layers that are familiar and seem suitable to the person skilled in the art for achieving a barrier effect with respect to light, vapour and/or gas. Especially preferred are metal oxide layers based on the metals already mentioned above, aluminium, iron or copper, and those metal oxide layers based on titanium oxide or silicon oxide compounds. A metal oxide layer is produced by way of example by vapour deposition of metal oxide on a polymer layer, for example an oriented polypropylene film. A preferred process for this purpose is physical gas phase deposition.

In a further preferred embodiment, the metal layer or metal oxide layer may take the form of a layer composite composed of one or more polymer layers with a metal layer. Such a layer is obtainable, for example, by vapour deposition of metal on a polymer layer, for example an ori ented polypropylene film. A preferred process for this purpose is physical gas phase deposition. Outer face

The outer face of the sheetlike composite is a surface of a ply of the sheetlike composite which is intended to be in contact with the environment of the container in a container to be produced from the sheetlike composite. This does not oppose, in individual regions of the container, fold ing of the outer faces of various regions of the composite against one another or joining thereof to one another, for example sealing thereof to one another.

Inner face

The inner face of the sheetlike composite is a surface of a ply of the sheetlike composite which is intended to be in contact with the contents of the container, preferably a food or drink product, in a container to be produced from the sheetlike composite.

Adhesion/adhesion promoter layer

An adhesion promoter layer may be present between layers of the sheetlike composite which do not directly adjoin one another, preferably between the barrier layer and the inner polymer layer. This adhesion promoter layer is also referred to herein as first adhesion promoter layer. Useful adhesion promoters in an adhesion promoter layer include all polymers which are suitable for producing a firm bond through functionalization by means of suitable functional groups, through the forming of ionic bonds or covalent bonds with a surface of a respective adjacent layer. Pref erably, these comprise functionalized polyolefins, especially acrylic acid copolymers, which have been obtained by copolymerization of ethylene with acrylic acids such as acrylic acid, methacrylic acid, crotonic acid, acrylates, acrylate derivatives or carboxylic anhydrides that bear double bonds, for example maleic anhydride, or at least two of these. Among these, preference is given to polyethylene-maleic anhydride graft polymers (EMAH), ethylene-acrylic acid copol ymers (EAA) or ethylene-methacrylic acid copolymers (EMAA), which are sold, for example, under the Bynel ^® and Nucrel ^® 0609HSA trade names by DuPont or the Escor ^® 6000ExCo trade name by ExxonMobil Chemicals.

Further preferably, useful adhesion promoters also include ethylene-alkyl acrylate copolymers. The alkyl group selected is preferably a methyl, ethyl, propyl, i-propyl, butyl, i-butyl or a pentyl group. Further preferably, the adhesion promoter layer may include mixtures of two or more different ethylene-alkyl acrylate copolymers. Likewise preferably, the ethylene-alkyl acrylate copolymer may have two or more different alkyl groups in the acrylate function, for example an ethylene-alkyl acrylate copolymer in which both methyl acrylate units and ethyl acrylate units occur in the same copolymer.

According to the invention, it is preferable that the adhesion between the carrier layer, a polymer layer or the barrier layer and the next layer in each case is at least 0.5 N/15 mm, preferably at least 0.7 N/15 mm and especially preferably at least 0.8 N/15 mm. In one configuration accord ing to the invention, it is preferable that the adhesion between a polymer layer and a carrier layer is at least 0.3 N/15 mm, preferably at least 0.5 N/15 mm and especially preferably at least 0.7 N/15 mm. It is further preferable that the adhesion between the barrier layer and a polymer layer is at least 0.8 N/15 mm, preferably at least 1.0 N/15 mm and especially preferably at least 1.4 N/15 mm. If the barrier layer indirectly follows a polymer layer with an adhesion promoter layer in between, it is preferable that the adhesion between the barrier layer and the adhesion promoter layer is at least 1.8 N/15 mm, preferably at least 2.2 N/15 mm and especially prefera bly at least 2.8 N/15 mm. In a particular configuration, the adhesion between the individual lay ers is sufficiently strong that the carrier layer is tom apart in an adhesion test, called a cardboard fibre tear in the case of a cardboard as the carrier layer.

Polyolefin

A preferred polyolefin is a polyethylene (PE) or a polypropylene (PP) or both. A preferred pol yethylene is one selected from the group consisting of an LDPE, an LLDPE, and an HDPE, or a combination of at least two of these. A further preferred polyolefin is an mPolyolefm (polyolefin prepared by means of a metallocene catalyst). Suitable polyethylenes have a melt flow rate (MFR = MFI - melt flow index) in a range from 1 to 25 g/10 min, preferably in a range from 2 to 20 g/10 min and especially preferably in a range from 2.5 to 15 g/10 min, and a density in a range from 0.910 g/cm ³ to 0.935 g/cm ³ , preferably in a range from 0.912 g/cm ³ to 0.932 g/cm ³ , and further preferably in a range from 0.915 g/cm ³ to 0.930 g/cm ³ . mPolymer

An mPolymer is a polymer which has been prepared by means of a metallocene catalyst. A metallocene is an organometallic compound in which a central metal atom is arranged between two organic ligands, for example cyclopentadienyl ligands. A preferred mPolymer is an mPoly- olefin, preferably an mPolyethylene or an mPolypropylene or both. A preferred mPolyethylene is one selected from the group consisting of an mLDPE, an mLLDPE, and an mHDPE, or a combination of at least two of these.

Melting temperatures

A preferred mPolyolefm is characterized by at least one first melting temperature and a second melting temperature. Preferably, the mPolyolefm is characterized by a third melting temperature in addition to the first and second melting temperature. A preferred first melting temperature is in a range from 84 to 108°C, preferably from 89 to 103°C, more preferably from 94 to 98°C. A preferred further melting temperature is in a range from 100 to 124°C, preferably from 105 to 119°C, more preferably from 110 to 114°C.

Extrusion

In the extrusion, the polymers are typically heated to temperatures of 210 to 350°C, measured at the molten polymer film beneath the exit from the extruder die. The extrusion can be effected by means of extrusion tools which are known to those skilled in the art and are commercially available, for example extruders, extruder screws, feed blocks, etc. At the end of the extruder, there is preferably an opening through which the polymer melt is pressed. The opening may have any shape that allows extrusion of the polymer melt. For example, the opening may be angular, oval or round. The opening is preferably in the form of a slot of a funnel. Once the melt layer has been applied to the substrate layer by means of the above-described method, the melt layer is left to cool down for the purpose of heat-setting, this cooling preferably being effected by quenching via contact with a surface which is kept at a temperature in a range from 5 to 50°C, especially preferably in a range from 10 to 30°C. Subsequently, at least the flanks are separated from the surface. The separation may be carried out in any way that is familiar and appears suitable to a person skilled in the art for separating the flanks quickly and as precisely and cleanly as possible. Preferably, the separation is effected by means of a knife, laser beam or waterjet, or a combination of two or more thereof, the use of knives being especially preferable, especially a circular knife.

Lamination

According to the invention, the carrier layer can be superposed by the barrier layer by lamina tion. In this case, the prefabricated carrier and barrier layers are joined with the aid of a suitable laminating agent. A preferred laminating agent comprises an intermediate polymer composition from which a polymer interlayer is preferably obtained. A further preferred laminating agent comprises an adhesion promoter composition from which an adhesion promoter layer is ob tained. Preferably, the laminating agent is applied by extrusion.

Colorant

Useful colorants include both solid and liquid colorants that are known to the person skilled in the art and are suitable for the present invention. According to DIN 55943 :2001-10, colorant is the collective term for all colouring substances, especially for dyes and pigments. A preferred colorant is a pigment. A preferred pigment is an organic pigment. Pigments that are notable in connection with the invention are especially the pigments mentioned in DIN 55943 :2001-10 and those mentioned in“Industrial Organic Pigments, Third Edition” (Willy Herbst, Klaus Hunger Copyright © 2004 WILEY- VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3-527-30576- 9). A pigment is a colorant that is preferably insoluble in the application medium. A dye is a colorant that is preferably soluble in the application medium.

Food or drink product

In the context of the invention, the sheetlike composite and the container precursor are preferably designed for production of a food or drink product container which is preferably closed. In ad dition, the container according to the invention is preferably a food or drink product container. Food and drink products include all kinds of food and drink known to those skilled in the art for human consumption and also animal feeds. Preferred food and drink products are liquid above 5°C, for example milk products, soups, sauces, non-carbonated drinks.

A container precursor is a precursor of the container which arises in the course of production of a container. In this context, the container precursor comprises the sheetlike composite preferably in the form of a blank. In this context, the sheetlike composite may be in an unfolded or folded state. A preferred container precursor has been cut to size and is designed for production of a single container. A preferred container precursor which has been cut to size and is designed for production of a single, preferably closed container is also referred to as a shell or sleeve. In this context, the shell or sleeve comprises the sheetlike composite in folded form. In addition, the container precursor preferably takes the form of an outer shell of a prism. A preferred prism is a cuboid. Moreover, the shell or sleeve comprises a longitudinal seam and is open in a top region and a base region. A typical container precursor which has been cut to size and is designed for production of a multitude of preferably closed containers is often referred to as a tube.

A further preferred container precursor is open, preferably in a top region or a base region, more preferably in both. A preferred container precursor is in the form of a shell or tube or both. A further preferred container precursor comprises the sheetlike composite in such a way that the sheetlike composite has been folded at least once, preferably at least twice, more preferably at least 3 times, most preferably at least 4 times. A preferred container precursor is in one-piece form. More preferably, a base region of the container precursor is in a one-piece design with a lateral region of the container precursor.

Container

The container according to the invention is preferably closed. In addition, the container accord ing to the invention may have a multitude of different forms, but preference is given to an es sentially cuboidal structure. In addition, the full area of the container may be formed from the sheetlike composite, or it may have a two-part or multipart construction. In the case of a multi part construction, it is conceivable that, as well as the sheetlike composite, other materials are also used, for example plastic, which can be used especially in the top or base regions of the container. In this context, however, it is preferable that the container is formed from the sheetlike composite to an extent of at least 50%, especially preferably to an extent of at least 70% and further preferably to an extent of at least 90% of the area. In addition, the container may have a device for emptying the contents. This may be formed, for example, from a polymer or mixture of polymers and be attached on the outer face of the container. It is also conceivable that this device has been integrated into the container by“ direct injection moulding" . In a preferred con figuration, the container according to the invention has at least one edge, preferably from 4 to 22 or else more edges, especially preferably from 7 to 12 edges. Edges in the context of the present invention are understood to mean regions which arise in the folding of a surface. Exam ples of edges include the longitudinal contact regions between two wall surfaces of the container in each case, also referred to as longitudinal edges herein. In the container, the container walls are preferably the surfaces of the container framed by the edges. Preferably, the interior of a container according to the invention comprises a food or drink product. Preferably, the container does not comprise any lid or base, or either, that has not been formed in one piece with the sheetlike composite. A preferred container comprises a food or drink product.

TEST METHODS

The following test methods were used within the context of the invention. Unless stated other wise, the measurements were conducted at an ambient temperature of 23°C, an ambient air pres sure of 100 kPa (0.986 atm) and a relative air humidity of 50%.

MFR

MFR is measured according to standard ISO 1133-1 :2012, Method A (mass determination method), unless stated otherwise at 190°C and 2.16 kg.

Density

Density is measured according to standard ISO 1183-1 :2013. Melting temperature

Melting temperature is determined on the basis of the DSC method ISO 11357-1, -5. The instru ment is calibrated according to the manufacturer's instructions on the basis of the following measurements:

- temperature indium onset temperature,

- heat of fusion indium,

- temperature zinc onset temperature.

Viscosity number of PA

The viscosity number of PA is measured according to the standard DIN EN ISO 307 (2013) in 95% sulfuric acid.

Molecular wei ht distribution

Molecular weight distribution is measured by gel permeation chromatography by means of light scattering: ISO 16014-3/-5 (2009-09).

Moisture content of cardboard

The moisture content of the cardboard is measured according to standard ISO 287:2009.

Adhesion

The adhesion of two adjacent layers is determined by fixing them in a 90° peel test instrument, for example the Instron“ German rotating wheel fixture”, on a rotatable roller which rotates at 40 mm/min during the measurement. The samples have been cut beforehand into strips 15 mm wide. On one side of the sample, the laminas are detached from one another and the detached end is clamped in a tensile device directed vertically upward. A measuring instrument to deter mine the tensile force is attached to the tensile device. As the roller rotates, the force needed to separate the laminas from one another is measured. This force corresponds to the adhesion of the layers to one another and is reported in N/15 mm. The separation of the individual layers can be effected mechanically, for example, or by means of a controlled pretreatment, for example by soaking the sample in 30% acetic acid at 60°C for 3 min. Detection of colorants

Detection of organic colorants can be conducted in accordance with the methods described in “Industrial Organic Pigments, Third Edition” (Willy Herbst, Klaus Hunger Copyright © 2004 WILEY- VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3-527-30576-9).

Bending resistance

Bending resistance is determined by the bending resistance method of standard ISO 2493- 2:2011. For the measurement, an L&W Bending Tester code 160 from Lorentzen & Wettre, Sweden, is used. As described in the standard, the samples that are used for determining the bending resistance of the carrier layer or of the sheetlike composite have a width of 38 mm and a clamped length of 50 mm. For the measurement, only samples without groove, fold or edge are used. The samples are taken in accordance with standard ISO 186. Bending resistance is ascertained by deflecting the sample by 15°. The bending test described in standard ISO 2493- 2:2011 is a 2-point bending test. For use in this document, a direction in which the carrier layer or the sheetlike composite has a bending resistance is a direction of a straight line that connects the 2 points of attack in the 2-point bending test. Preferably, this is the direction in which the carrier layer or the sheetlike composite bends as a result of the bending. At right angles to the direction of bending resistance, the carrier layer or sheetlike composite preferably forms a straight fold line when the sample is deflected far enough to fold it.

Edge wicking value

By means of a safety guillotine, 5 samples (dimensions: 170 mm x 70 mm) are cut out of the carrier layer to be examined. Cutting is effected here in such a way that the longer extent of the samples (170 mm) lies in the direction of orientation of the fibres of the cardboard. The samples are provided with adhesive tape on both sides such that the cardboard is completely sealed thereby. The safety guillotine is then used to cut the specimens provided with adhesive tape to the testing size of 150 mm ^c 50 mm. The samples are weighed, placed into a lactic acid bath of concentration 1% by weight, and pushed down to the base with a metal mesh (prevents the sam ples from floating). It is possible for the lactic acid solution coloured with 5 g of cochineal red per litre to penetrate into the cardboard via the exposed edges. After 24 hours, the samples are taken out, the excess lactic acid solution is dabbed off and the samples are weighed again. The difference in weight of the samples before the treatment in the lactic acid bath and thereafter is calculated and reported in kg/m ² as the edge wicking value. pH

The pH is determined using a conventional combination electrode, and the measurement is con ducted at 25 °C.

Fibre properties

The properties of the fibres, unless explicitly stated otherwise herein, are determined by the methods in the paper dictionary (Euwid Verlag; ISBN 3-88640-080-0).

Average fibre length

Average fibre length is determined to ISO 16065-2 with an L&W Fiber Tester.

Coarseness (fineness)

The fineness of a multitude of fibres is determined to ISO 9184 (1994) Part 1 to 7.

Integrity

The test medium used for integrity testing is Kristalloel 60 from Shell Chemicals with methylene blue. For this test, 250 containers are produced from the laminate to be examined as described below for the examples and comparative examples and closed. The closed containers are then each cut open around their circumference so as to obtain container portions open at the top in cluding closed base regions. These container portions are each filled with about 20 ml of the test medium and stored for 24 hours. After the storage time, the container portions are then inspected by the naked eye on the outer face of the base region as to whether the test medium, in the case of leaking of the base region, has produced blue colours there. The result reported for this test is the number of the 250 identical containers that show leakage after 24 hours. The invention is described in more detail hereinafter by examples and drawings, although the examples and drawings do not imply any restriction of the invention. Moreover, the drawings, unless stated otherwise, are not to scale. If the symbols ++, +, 0, - and— are used for evaluation of studies in the context of the examples and comparative examples, ++ means a more advanta geous result than +, + a more advantageous result than 0, 0 a more advantageous result than -, and - a more advantageous result than

Pulps

For each example and comparative example, a 3-ply cardboard layer is produced as carrier layer, which consists of a top ply, a middle ply and a back ply in that sequence. For this purpose, as described below, pulps are provided for the 3 different plies.

Pulp for the top ply:

A suspension of a mixture of ground wood fibres having a CSF ( Canadian Standard Freeness) of 450 and water is provided. The fibre mixture consists of 20% by weight of bleached short fibres and 80% by weight of bleached long fibres. The suspension is provided in a tank {machine chest), where the ratio of fibre mixture to water is adjusted so as to result in a solid consistency of 5% by weight. The pH of the suspension is adjusted to the value specified for the respective example or comparative example in Table 1 below by adding sulfuric acid. At the outlet of the tank, the sizing agent specified for the particular example or comparative example in Table 1 or the specified mixture of sizing agents is added in a concentration of 2.5 kg/ODT, based on the suspension with the sizing agent. The suspension is further diluted with water to a solid con sistency of 0.03% by weight and hence the pulp for the top ply is obtained.

Pulp for the middle ply:

A suspension of a mixture of ground wood fibres having a CSF of 350 and water is provided. The fibre mixture consists of 20% by weight of long fibres, 30% by weight of internal broke and 50% by weight of mechanical pulp. The suspension is provided in a tank (machine chest), where the ratio of fibre mixture to water is adjusted so as to result in a solid consistency of 4% by weight. The pH is adjusted to the value specified for the respective example or comparative example in Table 1 below by adding sulfuric acid. At the outlet of the tank, the sizing agent specified for the particular example or comparative example in Table 1 or the specified mixture of sizing agents is added in a concentration of 2.5 kg/ODT, based on the suspension with the sizing agent. The suspension is further diluted with water to a solid consistency of 0.03% by weight and hence the pulp for the middle ply is obtained.

Pulp for the back ply:

A suspension of a mixture of ground wood fibres having a CSF of 450 and water is provided. The fibre mixture consists to an extent of 100% by weight of unbleached long fibres. The sus- pension is provided in a tank (machine chest), where the ratio of fibre mixture to water is ad justed so as to result in a solid consistency of 5% by weight. The pH is adjusted to the value specified for the respective example or comparative example in Table 1 below by adding sulfuric acid. At the outlet of the tank, the sizing agent specified for the particular example or compara tive example in Table 1 or the specified mixture of sizing agents is added in a concentration of 2.5 kg/ODT, based on the suspension with the sizing agent. The suspension is further diluted with water to a solid consistency of 0.03% by weight and hence the pulp for the back ply is obtained.

Table 1 : pH values of the pulps used for the individual plies and the sizing agents used therein in the inventive examples and the non-inventive comparative examples, always using Eka DR C222 as AKD and Eka CRL44HT as rosin, both available from Akzo Nobel N. V. Production of the carrier layer from the pulps

For production of the cardboard layers for the inventive examples and the non-inventive com parative examples, the pulp for the top ply passes through a sorting screen and is then fed to the headbox (Sandusky Walmsley) for the top ply. The additive Corshell 61067 ^® from Ecolab Deutschland GmbH is fed in here in a concentration of 0.2 kg/ODT. Subsequently, the pulp for the top ply is dewatered with a Fourdrinier wire (manufacturer: Sandusky Walmsley) down to a solids content of 15% by weight. Subsequently, the pulp for the middle ply passes through a sorting screen and is then fed to the headbox (Sandusky Walmsley) for the middle ply. The additive Corshell 61067 ^® from Ecolab Deutschland GmbH is fed in here in a concentration of 0.29 kg/ODT. Thereafter, the pulp for the middle ply is dewatered with a Fourdrinier wire (man- ufacturer: Sandusky Walmsley) down to a solids content of 15% by weight. In addition, the pulp for the back ply passes through a sorting screen and is then fed to the headbox from Sandusky Walmsley for the back ply. The additive Corshell 61067 ^® from Ecolab Deutschland GmbH is fed in here in a concentration of 0.15 kg/ODT. Thereafter, the pulp for the back ply is dewatered with a Fourdrinier wire (manufacturer: Sandusky Walmsley) down to a solids content of 15% by weight. The pulp for the top ply is couched together with the pulp for the middle ply in the wet section (Sandusky Walmsley) and these two compositions are then couched with the pulp for the back ply to give a precursor of the carrier layer. The precursor is transferred into the pressing section and dewatered further to a solids content of 40% by weight. Thereafter, the precursor is sent to the drying section. By means of contact drying, the solids content is increased further therein to 93% by weight at cardboard web temperatures of 100°C.

The precursor thus dried is then sent to the paper coating apparatus (manufacturer: Jagenberg) in which, in two steps, a pigment paper coating is applied by means of paper coating units and then dried by means of air and infrared drying. The finished cardboard layer thus obtained is cut to a web length of 6000 m with a roll cutter (manufacturer: Jagenberg) and rolled up. The roll thus obtained is taken up with a lift truck of the Linde H 80 D-2 type from Linde, Aschaffenburg, Germany, with a 5-2244G clamp from Meyer GmbH, Salzgitter, Germany, and transferred to storage. The above-described uptake and transporting of the cardboard rolls by lift truck may result in "telescoping" of the cardboard roll. As a result, the cardboard roll comes apart and hence falls off the lift truck, which makes the cardboard roll unusable for further processing to lami nates for food and drink product containers. It is therefore highly desirable to avoid telescoping as far as possible. Table 3 below reports the tendency of the cardboard rolls produced in the examples and comparative examples to telescope on uptake and transporting by the lift truck. In addition, prior to the laminate production described below, cardboard layers produced by the examples and comparative examples are examined for their edge wicking value by the test method described above. This parameter is a measure of the tendency to absorb liquid. A mini mum edge wicking value of the laminate is indispensable for storage of liquid food or drink products in containers made from the laminate since laminates having a cardboard layer that shows an excessive tendency to absorb liquid can lead to a container that has stability and integ rity problems in the event of prolonged storage of liquid food or drink products and hence shelf life problems. Moreover, the containers produced in a filling machine are often moved onward on conveyor belts beyond the filling machine that are wetted with water as lubricant. Thus, the containers, even shortly after their production, come into contact with liquid on their outside, which, in the case of an excessive tendency of the cardboard layer to absorb liquid, can lead to the aforementioned stability, integrity and shelf life problems. The results are likewise reported in Table 3 below.

Laminate construction

Using the cardboard layers obtained as described above as carrier layers, for Examples 1 to 3 (inventive) and for the comparative examples (non-inventive), laminates having the layer con struction specified in Table 2 below and the layer sequence shown are each prepared by a layer extrusion process. Table 2 shows the outer face of the laminate at the top and its inner face at the bottom.

Table 2: Construction of the laminates to be used for the examples and comparative examples, using the carrier layer produced in each case in the example or comparative example as described above Laminate production

The laminates are produced with an extrusion coating system from Davis Standard. The extru sion temperature here is in a range from about 280 to 330°C. In the first step, the outer polymer layer is applied to the carrier layer. In the second step, the polymer interlayer is applied together with the barrier layer to the carrier layer that has been coated with the outer polymer layer be forehand. In the last step, the inner polymer layer is applied to the barrier layer. For application of the individual layers, the polymers are melted in an extruder. For application of a polymer in a layer, the resultant melt is transferred via a feed block into a nozzle and extruded onto the carrier layer.

In the laminates thus produced, adhesion between the carrier layer and the polymer interlayer and adhesion between the carrier layer and the outer polymer layer are ascertained by the test method described above. As described in the test method, in the measurement, the force exerted is increased until the two plies separate from one another. The force thus ascertained corresponds to the adhesion. In the present case of a cardboard layer as carrier layer, however, it may be the case that the cardboard layer already breaks up at a lower force (cardboard fibre tear) than would be necessary to overcome the adhesion between the cardboard layer and the corresponding ad- jacent layer (polymer interlayer or outer polymer layer). In such a case, the adhesion ascertained corresponds to the force at which the cardboard fibre tear occurs. This case occurs especially when one or more plies of the cardboard layer have been insufficiently sized, which can in turn result from the obtaining of the respective ply of the cardboard layer from a fibre suspension having unsuitable pH. The results of these examinations are likewise summarized in Table 3.

Table 3: Properties of the laminates and cardboard rolls according to Examples 1 to 3 and the comparative examples

The examination results summarized in Table 3 show that only the inventive examples provide laminates with a practicable combination of sufficient to good adhesion, low tendency of the cardboard layer to absorb liquid and low tendency to production of reject material through tele scoping. Thus, the laminates from the inventive examples are particularly suitable for production of dimensionally stable containers for storage of liquid food or drink products over compara tively long shelf lives. Moreover, comparatively little reject material occurs in production through telescoping.

Container production

Laminates from Examples 1 to 3 and comparative examples are additionally used to produce food or drink product containers. For this purpose, grooves, especially 4 longitudinal grooves per container, which define folding lines for the longitudinal edges of the containers to be pro duced, are introduced into the outer face (outer polymer layer side) of the laminates obtained as described above. In addition, the grooved laminate is divided into blanks for individual contain ers. By folding along the 4 longitudinal grooves of each and every blank and sealing of overlap ping fold faces by introduction of heat, a shell-shaped container precursor of the shape shown in Figure 8 with a longitudinal seam is obtained in each case. This shell is used to produce a closed container of the shape (brick type) shown in Figure 9 in a CFA 712 standard filling machine, SIG Combibloc, Linnich. This involves producing a base region by folding and sealing by heat sealing. This gives rise to a beaker open at the top. The beaker is sterilized with hydrogen per oxide. In addition, the beaker is filled with orange juice. By folding and ultrasound sealing, the top region of the beaker is closed and hence a closed container is obtained. Containers thus obtained are tested for their integrity by the above test method. The examination results compiled in Table 4 demonstrate that the inventive examples afford particularly impervious containers. These are consequently suitable for storage of liquid food or drink products over comparatively long shelf lives.

Table 4: Examination results for integrity of the containers according to Examples 1 to 3 and comparative examples

The figures respectively show, unless stated otherwise in the description or the respective figure in schematic form and not to scale: Figure 1 a flow diagram of a method according to the invention for producing a carrier layer;

Figure 2 a flow diagram of a further method according to the invention for producing a carrier layer;

Figure 3 a schematic diagram of a section of a carrier layer according to the invention in cross section;

Figure 4 a schematic diagram of a section of a sheetlike composite according to the invention in cross section;

Figure 5 a schematic diagram of a section of a further sheetlike composite according to the invention in cross section;

Figure 6 a flow diagram of a method according to the invention for producing a sheet like composite;

Figure 7 a flow diagram of a further method according to the invention for producing a sheetlike composite;

Figure 8 a schematic diagram of a container precursor according to the invention; and

Figure 9 a schematic diagram of a closed container according to the invention.

Figure 1 shows a flow diagram of a method 100 according to the invention for producing a carrier layer 300. In a method step a) 101, a first, a second and a third composition are provided. The first composition has a first pH and contains water 201 in a first water content, a first mul- titude of fibres 202, and a first sizing agent 207. The second composition has a second pH and contains water 201 in a second water content, a second multitude of fibres 203, and a second sizing agent 208. The third composition has a third pH and contains water 201 in a third water content, a third multitude of fibres 204, and a further content of the first sizing agent 207. The method 100 further includes a method step b) 102 in which a layer sequence comprising, as mutually superposed layers in this sequence, a first sheetlike layer 301, a second sheetlike layer 302 and a third sheetlike layer 303 is generated. In method step b) 102, the first sheetlike layer 301 is generated from the first composition. For this purpose, the first water content is reduced. In the course of this, the content of the first sizing agent 207 from the first composition surrounds the fibres from the first multitude of fibres 202 and fixes these through the formation of van der Waals bonds. Thus, the fibres of the first multitude of fibres 202 are sized. In addition, in method step b) 102, the second sheetlike layer 302 is generated from the second composition. In the course of this, the second water content is reduced and the second sizing agent 208 is crosslinked, which results in sizing of the fibres of the second multitude of fibres 203. In addition, the third sheetlike layer 303 is generated from the third composition in method step b) 102. This com prises reducing the third water content, wherein the further content of the first sizing agent 207 from the third composition surrounds the fibres from the third multitude of fibres 204 and fixes these through the formation of van der Waals bonds. Thus, the fibres of the third multitude of fibres 204 are sized. According to the invention, the first pH and the third pH in method step a) 101 are each less than the second pH. The first and third pH here are each less than 7, and the second pH is greater than 7. The first sizing agent 207 here is chemically modified natural rosin; the second sizing agent 208 is AKD.

Figure 2 shows a flow diagram of a further method 100 according to the invention for producing a carrier layer 300. Figure 2 here illustrates the production of the carrier layer 300 of the above- described inventive Example 3. According to Example 3, one pulp is provided for the top ply, one for the middle ply and one for the back ply, each of the carrier layer 300, by means of one machine chest 206 each. For this purpose, water and fibres are introduced into each of the three machine chests 206 in order to obtain a suspension in each.

For production of the pulp for the top ply, a first multitude of fibres 202 is used, which is a ground fibre mixture having a CSF of 450, composed of 20% by weight of bleached short fibres and 80% by weight of bleached long fibres. The solids consistency of the suspension for pulp for the top ply is adjusted to 5% by weight. The pH is adjusted to 6.8 by addition of sulfuric acid 205. At the outlet from the machine chest 206, Eka CRL44HT from Akzo Nobel N.V. is added as first sizing agent 207 in a concentration of 2.5 kg/ODT. The suspension is further diluted with water to a solids consistency of 0.03% by weight and hence pulp for the top ply is obtained.

For production of the pulp for the middle ply, a second multitude of fibres 203 is used, which is a ground fibre mixture having a CSF of 350, composed of 20% by weight of long fibres, 30% by weight of internal broke and 50% by weight of mechanical pulp. The solids consistency of the suspension for pulp for the middle ply is adjusted to 4% by weight. The pH is adjusted to 7.8 with sulfuric acid 205. At the outlet from the machine chest 206, Eka DR C222 from Akzo Nobel

N.V. is added as second sizing agent 208 in a concentration of 2.5 kg/ODT. The suspension is further diluted with water to a solids consistency of 0.03% by weight and hence pulp for the middle ply is obtained.

For production of the pulp for the back ply, a third multitude of fibres 204 is used, which is a ground fibre mixture having a CSF of 450, composed of 100% by weight of unbleached long fibres. The solids consistency of the suspension for pulp for the back ply is adjusted to 5% by weight. The pH is adjusted to 6.8 by addition of sulfuric acid 205. At the outlet from the machine chest 206, Eka CRL44HT from Akzo Nobel N.V. is added as first sizing agent 207 in a concen tration of 2.5 kg/ODT. The suspension is further diluted with water to a solids consistency of

O.03% by weight and hence pulp for the back ply is obtained.

Thus, in a method step a) 101 of method 100, the 3 pulps are obtained as the first to third com position. The method 100 further includes a method step b) 102 in which the carrier layer 300 is obtained from the first to third compositions. The exact procedure for method step b) 102 is described above for Example 3. Figure 2 illustrates the sequence of sorting screens 209 for each of the first to third compositions, addition of the additive 210 Corshell 61067 ^® from Ecolab Deutschland GmbH to each of the first to third compositions, headbox 211 for the respective sheetlike layer 301 to 303, wire sections for the respective sheetlike layers 301 to 303, couching 213 of the first and second compositions and of the latter two with the third composition to give a precursor of the carrier layer 300, the pressing section 214, the drying section 215, the paper coating system 216 with squeegee and paper coating tank with paper coating composition, the IR and hot air dryer 217, the roll cutter 218 for cutting the carrier layer 300 to size and for rolling- up 219 the carrier layer 300 that has been cut to size. The resultant carrier layer 300 is a paper- coated cardboard having top ply, middle ply and back ply. Figure 3 shows a schematic diagram of a detail of a carrier layer 300 according to the invention in cross section. The carrier layer 300 shown is obtainable by the method 100 of Figure 2. Figure 3 shows the layer sequence of the carrier layer 300 with the first sheetlike layer 301, the second sheetlike layer 302 and the third sheetlike layer 303 as top ply, middle ply and back ply. The carrier layer 300 has a Scott bond value of 240 J/m ² , and a bending resistance of 180 mN in a first direction and of 140 mN in a direction at right angles to the first direction. Figure 3 also shows a first layer side 304 and an opposite further layer side 305 of the carrier layer 300.

Figure 4 shows a schematic diagram of a section of a sheetlike composite 400 according to the invention in cross section. The sheetlike composite 400 consists of the following layers of a layer sequence in the direction from an outer face 401 of the sheetlike composite 400 to an inner face 402 of the sheetlike composite 100: a carrier layer 300 with a first layer side 304 and an opposite further layer side 305, a barrier layer 403 and an inner polymer layer 404. The carrier layer 300 is the cardboard layer obtainable by means of the method 100 of Figure 2, with the first to third sheetlike layers 301 to 303. The first sheetlike layer 301 here is the top ply, the second sheetlike layer 302 the middle ply, and the third sheetlike layer 303 the back ply. The barrier layer 403 consists of EVOH, available as EVAL L171B from Kuraray, Diisseldorf, Ger many. The inner polymer layer 404 consists of a blend of 65% by weight of LDPE 19N430 from Ineos GmbH, Cologne, Germany and 35% by weight of Eltex 1315 A Z from Ineos GmbH, Co logne, Germany.

Figure 5 shows a schematic diagram of a section of a further sheetlike composite 400 according to the invention in cross section. The sheetlike composite 400 consists of the following layers in a layer sequence in a direction from an outer face 401 of the sheetlike composite 400 to an inner face 402 of the sheetlike composite 400: an outer polymer layer 501, an ink application 502 which is a decoration of the sheetlike composite 400, a carrier layer 300, a polymer interlayer 503, a barrier layer 403, an adhesion promoter layer 504 and an inner polymer layer 404. The outer polymer layer 501 consists of LDPE 19N430 from Ineos GmbH, Cologne, Germany. The carrier layer 300 is the cardboard layer obtainable by means of the method 100 of Figure 2, wherein the top ply thereof faces the outer polymer layer 501. The polymer interlayer 503 consists to an extent of 100% by weight of LDPE 23L430 from Ineos GmbH, Cologne, Ger many. The barrier layer 403 is an aluminium foil having the EN AW 8079 name from Hydro Aluminium Deutschland GmbH. The adhesion promoter layer 504 consists of EAA Escor 6000 from Exxon Mobil Corporation. The inner polymer layer 404 consists, in a direction from the barrier layer 403 to the inner face 402, of the following three sublayers: a first sublayer 505 composed of 75% by weight of HDPE and 25% by weight of LDPE, based in each case on the total weight of the first sublayer 505, a second sublayer 506 composed of 100% by weight of LDPE based on the total weight of the second sublayer 506 and a third sublayer 507 composed of a polymer blend, where the polymer blend consists to an extent of 30% by weight of an mPE and to an extent of 70% by weight of an LDPE, based in each case on the total weight of the third sublayer 507.

Figure 6 shows a flow diagram of a method 600 according to the invention for production of a sheetlike composite 400. In a method step a. 601, the carrier layer 300 from Figure 3 is provided. First of all, the carrier layer 300 is coated on a further layer side 305, opposite a first layer side 304, by means of layer extrusion with an outer polymer layer 501 composed of LDPE 19N430 from Ineos GmbH, Cologne, Germany. In a downstream method step b. 602, the carrier layer 300 is superposed with a barrier layer 403 on the first layer side 304 of the carrier layer 300. The barrier layer 403 is an EN AW 8079 aluminium foil from Hydro Aluminium Deutschland GmbH, having a thickness of 6 pm. For lamination of the barrier layer 403 to the carrier layer 300, in method step b., a polymer interlayer 503 consisting of LDPE 23L430 from Ineos GmbH, Cologne, Germany, is introduced between the carrier layer 300 and the barrier layer 403. In a method step c. 603, the barrier layer 403 is coated by means of coextrusion on a side of the barrier layer 403 remote from the carrier layer 300 with an adhesion promoter layer 504 and an inner polymer layer 404. The adhesion promoter layer 504 consists of EAA Escor 6000 from Exxon Mobil Corporation. The inner polymer layer 404 consists of a blend of 65% by weight of LDPE 19N430 from Ineos GmbH, Cologne, Germany and 35% by weight of Eltex 1315 AZ from Ineos GmbH, Cologne, Germany. In a subsequent method step c., the outer polymer layer 501 is printed on a side remote from the carrier layer 300 with an ink application 502 in order to obtain a decoration. Grooves 805 are introduced into the sheetlike composite 400 thus produced, such that, by folding along these grooves 805 and joining particular regions of the folded sheet like composite 400, containers 900 can be formed from the sheetlike composite 400. For this purpose, a grooving tool acts mechanically on the sheetlike composite 400 and produces linear depressions in the carrier layer 300, called grooves 805. Downstream of that, the grooved sheet like composite 400 is cut to size to form a multitude of blanks, in each case for production of a single closed container 900. These blanks can be processed further to form shell-like container precursors 800.

Figure 7 shows a flow diagram of a further method 600 according to the invention for production of a sheetlike composite 400. In a method step a. 601, the carrier layer 300 from Figure 3 is provided. First of all, the carrier layer 300 is printed on a further layer side 305 opposite a first layer side 304 with an ink application 502. In a downstream method step b. 602, the carrier layer 300 is superposed with a barrier layer 403 on the first layer side 304 of the carrier layer 300. In a method step c. 603, the barrier layer 403 is superposed on a side of the barrier layer 403 remote from the carrier layer 300 with an inner polymer layer 404 and hence a sheetlike composite 400 is obtained.

Figure 8 shows a schematic diagram of a container precursor 800 according to the invention. The container precursor 800 includes a blank of the sheetlike composite 400 obtained by the method 600 of Figure 6 with 4 longitudinal folds 801, each of which forms a longitudinal edge 801. In the container precursor 800, the outer face 401 of the sheetlike composite 400 faces outward. The container precursor 800 is in the form of a shell and comprises a longitudinal seam 802 in which a first longitudinal edge and a further longitudinal edge of the sheetlike composite 400 are sealed to one another. By folding along grooves 805 and joining fold regions in a top region 803 and a base region 804 of the container precursor 800, a closed container 900 is ob tainable. Such a container 900 is shown in Figure 9.

Figure 9 is a schematic diagram of a container 900 according to the invention, which is a closed container 900 of the brick type. The container 900 has been produced from the container precur sor 800 according to Figure 8. Consequently, in the container 900, the outer face 401 of the sheetlike composite 400 faces outward. In its interior, the container 900 contains a food or drink product 901. In addition, the container has 12 edges. Figure 9 also shows longitudinal edges 801, the longitudinal seam 802, the closed top region 803, and the likewise closed bottom region 804.

LIST OF REFERENCE NUMERALS

Method according to the invention for producing a carrier layer Method step a)

Method step b)

Water

First multitude of fibres

Second multitude of fibres

Third multitude of fibres

Sulfuric acid

Machine chest

First sizing agent

Second sizing agent

Sorting screen

Additive

Headbox

Wire section

Couching

Pressing section

Drying section

Paper coating system

IR and hot air dryer

Roll cutter

Rolling-up

Carrier layer according to the invention

First sheetlike layer

Second sheetlike layer

Third sheetlike layer

First layer side

Further layer side Sheetlike composite according to the invention

Outer face

Inner face

Barrier layer

Inner polymer layer

Outer polymer layer

Ink application

Polymer interlayer

Adhesion promoter layer

First sublayer of the inner polymer layer

Second sublayer of the inner polymer layer

Third sublayer of the inner polymer layer

Method according to the invention for production of a sheetlike composite Method step a.

Method step b.

Method step c.

Method step d.

Container precursor according to the invention

Longitudinal edge, longitudinal fold

Longitudinal seam

Top region

Base region

Groove

Container according to the invention

Food or drink product