Barrier papers

Abstract

A barrier paper for packaging frozen goods, wherein the barrier paper comprises a multilayer barrier structure, comprising, or consisting of, in this order, - a first barrier layer, - a first barrier pre-coat layer, - a base paper layer, - a second barrier pre-coat layer,0 - a second barrier layer, wherein the first and second barrier pre-coat layer comprise a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the first and second barrier pre-coat layer, wherein the first and second barrier layer comprise a barrier agent comprising or consisting of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more and wherein the barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

Description

[0001] F07341 19.09. 2024

[0002] 1

[0003] TITLE

[0004] BARRIER PAPERS

[0005] TECHNICAL FIELD

[0006] The present invention relates to a barrier paper for packaging frozen confectionery, and other goods.

[0007] PRIOR ART

[0008] In general, packaging allows to protect perishable goods from outside factors such as molds, bacteria, gases such as oxygen and moisture. This allows to extend the shelf life of the packaged goods and reduces the occurrence of food waste.

[0009] In the past, composite packaging papers consisting of a multitude of different layers, each conferring a specific barrier property, were successfully used. However, these layers were made of polymer films or metal layers and were laminated or glued together, making it difficult to separate them from each other and recycle them. This meant that their disposal meant either landfilling or incinerating.

[0010] However, with the ever-increasing need of recuperating base materials to transition towards a more sustainable packaging industry, legislation is being enacted that requires packaging papers to be easily recyclable. In analogy to other paper-based products such as newsprint, packaging papers should be re-pulpable without the need to first isolate and eliminate the metal layers and / or polymer film layers.

[0011] At the same time, such packaging papers should have the same barrier properties as composite packaging papers such as for example oil and / or grease barrier, oxygen barrier and water vapor barrier. In addition, when the foodstuffs to be packaged are to be stored at freezing temperature, the properties should extend over the breadth of the temperature range spanning from temperature at storage, at production and at consumption.

[0012] Likewise, when a foodstuff to be packaged is packaged in packaging paper, the packaging F07341 19.09. 2024

[0013] 2 paper is often folded, bent, crumpled or crimped heavily. In most cases, such a packaging paper also serves a decorative purpose, and comprises an image receiving layer that is printed. During packaging, bending the packaging paper can crack the image receiving layer, especially at the fold resulting from crimping, and cause the packaged product to appear less alluring.

[0014] Lastly, when the foodstuff to be packed is an individual portion such as for example an ice cream cone, the packaging apparatus is fed with pre-cut blanks of packaging paper that are stored in a stack. It is preferable that the pre-cut blanks are flat, i.e. without curling one side or the other because this is disruptive to the efficient functioning of the packaging apparatus. Furthermore, in some cases, the packaging paper should preferably be able to be heat sealed to itself, i.e., the outer surface should be capable of being heat-sealed to the inner surface.

[0015] There exists a need to provide a packaging paper that is free from metal layers and which is fully re-pulpable, and which provides excellent barrier properties against oil and / or grease, oxygen and moisture, even at freezing temperature, and which has no or very little propensity for bending / curling.

[0016] WO 2022 / 266329 A2 discloses an aqueous paper coating composition having water vapor barrier coating properties, including a base- and topcoat layer. The basecoat layer comprising an aqueous solution of ethylenically modified polyvinyl alcohol is applied and dried on the paper substrate and only then is a topcoat layer comprising an aqueous polymeric dispersion or emulsion applied and dried.

[0017] WO 2021 / 228695 A1 discloses a paper-based packaging material having a carrier paper and a first coating arranged indirectly or directly at least on one side of the carrier paper, wherein the first coating is a barrier layer and is arranged between the carrier paper and a visually perceivable surface coating and is in direct contact with the surface coating. The barrier layer may comprise a polymer of vinyl alcohol and may complemented by a layer of aluminum / aluminium.

[0018] DE 69807481 discloses a packaging cardboard for use in cups in which the metal layer can be eliminated for the sake of better recyclability, while providing equivalent barrier against liquids and gases. The barrier layer against liquids and gases, which may be applied both sides of the cardboard, is disclosed as containing large amounts of talcum together with a F07341 19.09. 2024

[0019] 3 binder polymer, which can be a polymer and copolymer of vinyl acetate. The barrier layer can be coated with a heat sealing layer that is based on LDPE or heat sealing lacquers.

[0020] WO 2006 / 007239 discloses a multilayer packaging material that is suitable as a lid for sealing to a plastic container. The multilayer packaging material comprises a infused paper substrate, a barrier layer of EVOH, a tie layer bonding the out seal-peel layer to the barrier layer. The different polymer layers are applied as a melt by extrusion and the outer layer of the packaging material may comprise a water-resistant pre-coat of clay and latex binder and a top coat of pigment of 17 to 22 parts of latex and 1 to 4 parts of polyvinyl alcohol binder, which is applied as a dispersion via an coater instead of as a melt via an extruder. The multi-layer composite structures of W02006 / 07239 are resistant to washing and rinsing but are not re-pulpable due to the melt extruded polymer layers and the melamine infusion of the base paper.

[0021] SUMMARY OF THE INVENTION

[0022] The present invention provides a packaging paper that is re-pulpable and devoid of metal layers and which provides excellent barrier properties against oil and / or grease, oxygen and moisture, at freezing temperature, and which has no or very little propensity for bending / curling. The packaging paper according to the present invention is particularly suitable for packaging frozen goods, such as for example ice cream or ice cream cones and exhibits barrier layers applied on both sides of the packaging paper.

[0023] It is therefore a first object of the present invention to provide a barrier paper for packaging frozen goods, wherein the barrier paper comprises a multilayer barrier structure, comprising, or consisting of, in this order, a first barrier layer comprising a first barrier composition comprising a first barrier agent, a first barrier pre-coat layer, a base paper layer having a rougher side and a smoother side, a second barrier pre-coat layer, a second barrier layer comprising a second barrier composition comprising a second barrier agent, wherein the first barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the first barrier pre-coat F07341 19.09. 2024

[0024] 4 layer, wherein the second barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the second barrier pre-coat layer, wherein the first barrier agent comprises or consists of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more and wherein the second barrier agent comprises, or consists of, a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

[0025] It is further a second object of the present invention to provide a process for producing a barrier paper according to the first object of the present invention, comprising the steps of: providing a base paper layer having a rougher side and a smoother side, applying an aqueous first barrier pre-coat composition to the rougher side of the base paper layer and drying the aqueous first barrier pre-coat composition to form a first barrier pre-coat layer, applying an aqueous first barrier composition to the first barrier pre-coat layer and drying the aqueous first barrier layer composition to form a first barrier layer, applying an aqueous second barrier pre-coat composition to the smoother side of the base paper layer and drying the aqueous second barrier pre-coat composition to form a second barrier pre-coat layer, applying an aqueous second barrier composition to the second barrier pre-coat layer and drying the aqueous second barrier layer composition to form a second barrier layer.

[0026] It is a further a third object of the present invention to provide a packaging comprising a barrier paper according to the first object of the present invention.

[0027] Further embodiments of the invention are laid down in the dependent claims.

[0028] DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] It is a first object of the present invention to provide a barrier paper, in particular for packaging frozen goods, wherein the barrier paper comprises a multilayer barrier structure, comprising, or consisting of, in this order, F07341 19.09. 2024

[0030] 5 a first barrier layer comprising a first barrier composition comprising a first barrier agent, a first barrier pre-coat layer, a base paper layer, which paper may in particular have a rougher side and a smoother side, a second barrier pre-coat layer, a second barrier layer comprising a second barrier composition comprising a second barrier agent, wherein the first barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the first barrier pre-coat layer, wherein the second barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the first barrier pre-coat layer, wherein the first barrier agent comprises or consists of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more and wherein the second barrier agent comprises or consists of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

[0031] In the context of the present invention, the term "water-soluble (co)polymer", in particular in the case of a polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, or a copolymer of vinyl alcohol and ethylene having a saponification level of 95.0 mol% or more and having an ethylene content of 15% or less, means that the polymer is soluble in water at 90°C in an amount of at least 40 mg / l, after 30 min or more.

[0032] In the context of the present invention, the term "essentially free of a material" means that the material is present in less than 0.1% w / w%, preferably less than 0.01 w / w%.

[0033] The base paper layer having a rougher side and a smoother side may be a paper as known in the art and is preferably based on a web of bleached chemical pulp such as bleached kraft or bleached sulphite pulp or mixtures thereof. In some embodiments, the base paper may include a sizing composition such as for example starch-based sizing or AKD-based sizing composition or rosin sizing. In some embodiments, the base paper may be produced F07341 19.09. 2024

[0034] 6 by allowing the wet paper web to dry against a highly-polished metal cylinder, also called a Yankee dryer. Such a paper that has been machine-glazed is also known as MG paper, and the base paper layer may be MG paper, where the smoother side corresponds to the side of the paper that was dried against the highly-polished metal cylinder.

[0035] The first barrier agent may be chosen from a water-soluble polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as polyvinyl alcohol, or copolymer of vinyl alcohol having a saponification level of 95.0 mol% or more, 98.0 mol% or more, such as ethylene vinyl alcohol, or mixtures thereof.

[0036] The second barrier agent may be chosen from a water-soluble polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as polyvinyl alcohol, or copolymer of vinyl alcohol having a saponification level of 95.0 mol% or more, 98.0 mol% or more, such as ethylene vinyl alcohol, or mixtures thereof.

[0037] The high level of saponification ensures an excellent barrier level performance, which allows to use lower coat weights, and thus contributing also to a higher level of sustainability.

[0038] The barrier paper according to the first object of the present invention is suitable for the packaging of frozen goods, in particular for packaging frozen foodstuff such as for example ice cream. The term ice cream is meant to generally include frozen desserts such as for example water-based sorbet, sherbet, and dairy-based ice creams such as frozen custards and the like. The application of the paper is not meant to be limited as to packaging of frozen goods, as the paper is equally suitable also for other purposes, including but not limited to i.e. secondary packaging.

[0039] The barrier paper according to the first object of the present invention may exhibit a barrier effect against grease, oils, water vapor and / or oxygen. It was found that a barrier paper having a combined coat weight of the first and second barrier layers of approximately 5 gsm exhibited the properties as mentioned below.

[0040] The barrier paper according to the first object of the present invention may exhibit a barrier effect against grease according to TAPPI Test Method T559 of a KIT value of 10 or more, preferably of 11 or more, and more preferably of 12. Because the barrier paper according to the present invention comprises barrier layers (and the underlying barrier pre-coat layers) on both sides of the base paper layer, the grease barrier effect is present on both sides of F07341 19.09. 2024

[0041] 7 the barrier paper; whichever side is tested, it thus exhibits a barrier effect against grease according to TAPPI Test Method T559 of a KIT value of 10 or more, preferably of 11 or more, and more preferably of 12 .when tested on any one of the two sides, i.e. the rough side and the smooth side. This is exceptionally useful when the barrier paper is used in packaging frozen goods such as ice cream or ice cream cones.

[0042] The barrier paper according to the first object of the present invention may exhibit a barrier effect against water vapor at -18°C and 100% relative humidity of 0.5 gsm / day or less, preferably of 0.2 gsm / day or less, most preferably of 0.1 gsm / day or less, when measured via ISO 15106-2 on an PERMATRAN-W 3 / 34 WVTR Analyzer.

[0043] The barrier paper according to the first object of the present invention may exhibit a barrier effect against water vapor at 23°C and 50% relative humidity of 6.0 gsm / day or less, preferably of 4.0 gsm / day or less, more preferably below 3.0 gsm / day, more preferably below 2.0 gsm / day, when measured via ISO 15106-2 on an PERMATRAN-W 3 / 34 WVTR Analyzer.

[0044] The barrier paper according to the first object of the present invention may exhibit a barrier effect against oxygen at 23°C and 50% relative humidity of 6.0 cc / (m2.day) or less, preferably of 4.0 cc / (m2.day) or less, more preferably below 2.0 cc / (m2.day) , when measured via DIN 53 380-3 on an OX-TRAN 2 / 22 OTR-Analyzer with COU LOX-Sensor.

[0045] The barrier paper according to the first object of the present invention may exhibit no substantial signs of print cracking at the fold (OAF) even at varying conditions such as the ones encountered in ice cream production, which can oscillate between standard conditions and deep-freezing conditions.

[0046] The barrier paper according to the first object of the present invention may exhibit an excellent flatness and curl stability, i.e. curl remains unchanged, even when subjected to changing environmental conditions such as changes in relative humidity. The symmetry in coatings that the barrier paper of the present invention possesses confers a resistance against curling, because both sides of the barrier paper will react in an identical fashion to a change in humidity and any stress / tension in one coating is canceled out by the coating on the opposing side of the barrier paper.

[0047] The barrier paper according to the first object of the present invention may exhibit a F07341 19.09. 2024

[0048] 8

[0049] MOSH / MOAH performance, using n-hexane as trace of as low as 0.2 g / m2at 23°C / 50%rh.

[0050] In a preferred embodiment, the barrier paper according to the first object of the present invention does not comprise a metal layer, meaning that it does not include, for example, a metal layer such as a metal foil that is laminated to a layer of the multilayer barrier structure or that it does not include, for example, a thin metal layer deposited via PVD / CVD / ALD technique on a layer of the multilayer barrier structure, as the barrier paper according to the first object of the present invention can provide the needed barrier properties such as grease barrier, oil barrier, moisture barrier and oxygen barrier without a metal layer.

[0051] Without a metal layer, the paper can be more easily recycled, as a metal layer does not need to be removed from the barrier paper according to the first object of the present invention before it can be re-pulped. Thus, advantageously, the barrier paper according to the first object of the present invention is recyclable, according to current recycling test methods, specifically CEPI harmonized test method (V.2, Rev. 08 / 2022-09-27) and 4EG evaluation protocol (beta version, Dec 2022).

[0052] The barrier paper according to the first object of the present invention comprises a multilayer barrier structure which provides the needed barrier properties. The multilayer barrier structure includes multiple layers in a specific order, which order within the multilayer barrier structure gives rise to the advantages of the barrier paper according to the first object of the present invention. It is understood that the barrier paper according to the first object of the present invention comprises said multilayer barrier structure and may, in addition to the multilayer barrier structure, comprise other layers such an additional and dedicated image receiving layer or an adhesive layer, even though the first and second barrier layer are printable without the need of further layers. Alternatively, the barrier paper according to the first object of the present invention may consist of the multilayer barrier structure, i.e., without including additional layers.

[0053] The barrier paper according to the first object of the present invention comprises a multilayer barrier structure, comprising, or consisting of, in this order, a first barrier layer comprising a first barrier composition comprising a first barrier agent, a first barrier pre-coat layer, a base paper layer having a rougher side and a smoother side, a second barrier pre-coat layer, a second barrier layer comprising a second barrier composition comprising a second barrier agent. F07341 19.09. 2024

[0054] 9

[0055] In one embodiment of the barrier paper according to the first object of the present invention, in the first barrier layer comprising a first barrier composition comprising or consisting of a first barrier agent and in the second barrier layer comprising or consisting of a second barrier composition comprising a second barrier agent, the first barrier agent and the second barrier agent may be different within the limits of the invention as described herein. For example, in the first barrier layer comprising a first barrier composition comprising or consisting of a first barrier agent, the first barrier agent may be a water-soluble polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as polyvinyl alcohol, whereas in the second barrier layer comprising a second barrier composition comprising or consisting of a second barrier agent, the second barrier agent may be the copolymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as ethylene vinyl alcohol, or mixtures thereof.

[0056] In one embodiment of the barrier paper according to the first object of the present invention, in the first barrier layer comprising a first barrier composition comprising or consisting of a first barrier agent and in the second barrier layer comprising or consisting of a second barrier composition comprising a second barrier agent, the first barrier agent and the second barrier agent may be the same, and in particular, the first barrier layer and the second barrier layer may be identical in composition. For example, in the first barrier layer comprising a first barrier composition comprising or consisting of a first barrier agent, the first barrier agent may be a water-soluble polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as polyvinyl alcohol, and in the second barrier layer comprising a second barrier composition comprising or consisting of a second barrier agent, the second barrier agent may be a water-soluble polymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as polyvinyl alcohol. Or for example, in the first barrier layer comprising a first barrier composition comprising or consisting of a first barrier agent, the first barrier agent may be a water-soluble copolymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as ethylene vinyl alcohol, and in the second barrier layer comprising a second barrier composition comprising or consisting of a second barrier agent, the second barrier agent may be a water-soluble copolymer of vinyl alcohol having a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, such as ethylene vinyl alcohol.

[0057] The first barrier layer, the first barrier composition may comprise other compounds beyond the first barrier agent and in the second barrier layer, the second barrier composition may F07341 19.09. 2024

[0058] 10 comprise other compounds beyond the second barrier agent. Such compounds may be for example additives, such as antimicrobial or antifungal additives, coloring additives such as dyes, rheological additives and antifoaming additives and the like.

[0059] It is noted that the first and second barrier layer, in particular when the first and second barrier composition comprise ethylene vinyl alcohol as the barrier agent, can directly receive a print image, via known printing processes such as for example ink-jet printing or off-set printing. Furthermore, the second barrier layer, when applied on the smoother side of the base paper layer, is particularly well-suited to receive a print image via rotogravure printing, which requires a very smooth print receiving surface.

[0060] The first barrier pre-coat layer comprises a binder polymer and a pigment, where preferably the amount of binder polymer is of from 15 to 50 % by weight, preferably of from 20 to 25% by weight, or from 25 to 30% by weight, and the amount of pigment is of from 50 to 85 % by weight, preferably of from 70 to 75 % by weight or from 75 to 80% by weight, based on the weight of the first barrier pre-coat layer. It is understood that the first binder polymer may be any suitable binder polymer known in the art and is preferably a polymer that is not a polymer of vinyl alcohol or a copolymer of vinyl alcohol. Thus, in one embodiment the binder polymer is essentially free of a polymer of vinyl alcohol or a copolymer of vinyl alcohol or comprises less than 10% by weight, more preferably less than 5% by weight of a polymer of vinyl alcohol or a copolymer of vinyl alcohol, based on the total weight of binder polymer. Thus, in an embodiment, the binder polymer is a mixture of two (or more) polymers, where one polymer is not a polymer of vinyl alcohol or a copolymer of vinyl alcohol and where the other polymer is a polymer of vinyl alcohol or a copolymer of vinyl alcohol where the polymer of vinyl alcohol or a copolymer of vinyl alcohol is comprised in an amount of less than 10% by weight, more preferably less than 5% by weight, based on the total weight of binder polymer.

[0061] The second barrier pre-coat layer comprise a binder polymer and a pigment, where preferably the amount of binder polymer is of from 15 to 50 % by weight, preferably of from 20 to 25% by weight, or from 25 to 30% by weight, and the amount of pigment is of from 50 to 85 % by weight, preferably of from 70 to 75 % by weight or from 75 to 80% by weight, based on the weight of the second barrier pre-coat layer. It is understood that the second binder polymer may be any suitable binder polymer known in the art and is preferably a polymer that is not a polymer of vinyl alcohol or a copolymer of vinyl alcohol. Thus, in one embodiment the binder polymer is essentially free of a polymer of vinyl alcohol or a F07341 19.09. 2024

[0062] 11 copolymer of vinyl alcohol, or comprises less than 10% by weight, more preferably less than 5% by weight of a polymer of vinyl alcohol or a copolymer of vinyl alcohol, based on the total weight of binder polymer. Thus, in an embodiment, the binder polymer is a mixture of two polymers, where one polymer is not a polymer of vinyl alcohol or a copolymer of vinyl alcohol and where the other polymer is a polymer of vinyl alcohol or a copolymer of vinyl alcohol, where the polymer of vinyl alcohol or a copolymer of vinyl alcohol is comprised in an amount of less than 10% by weight, more preferably less than 5% by weight, based on the total weight of binder polymer.

[0063] In one embodiment of the barrier paper according to the first object of the present invention, in the first barrier pre-coat layer comprising or consisting of a binder polymer and a pigment and in the second barrier pre-coat layer comprising or consisting of a binder polymer and a pigment, the binder agent and the pigment are the same in the first and second barrier precoat layer, and in particular the first and second barrier pre-coat layer are identical in composition.

[0064] In one embodiment of the barrier paper according to the first object of the present invention, in the first barrier pre-coat layer comprising or consisting of a binder polymer and a pigment and in the second barrier pre-coat layer comprising or consisting of a binder polymer and a pigment, the binder agent and the pigment agent in the first and second barrier pre-coat layer may be different within the limits of the invention as described herein.

[0065] The first barrier pre-coat layer may comprise other compounds beyond the binder agent and in the pigment, and the second barrier pre-coat layer may comprise other compounds beyond the binder agent and pigment. Such compounds may be for example additives, such as antimicrobial or antifungal additives, coloring additives such as dyes, rheological additives and antifoaming additives and the like.

[0066] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier agent and / or the second barrier agent is pinhole free.

[0067] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier pre-coat layer has weight of 1 gsm to 8 gsm, preferably of 2 gsm to 8 gsm, more preferably of 2.5 gsm to 3.5 gsm. Good results were achieved with the values of 4 gsm, 4.5 gsm, 5 gsm, 5.5 gsm, 6 gsm, 6.5 gsm, 7 gsm, 7.5 gsm. F07341 19.09. 2024

[0068] 12

[0069] In one embodiment of the barrier paper according to the first object of the present invention, the second barrier pre-coat layer has weight of 1 gsm to 8 gsm, preferably of 2 gsm to 6 gsm, more preferably of from 2.0 gsm to 2.5 gsm. Good results were achieved with the values of 4 gsm, 4.5 gsm, 5 gsm, 5.5 gsm, 6 gsm, 6.5 gsm, 7 gsm, 7.5 gsm.

[0070] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier agent and the second barrier agent is a copolymer of ethylene and vinyl alcohol such as ethylene vinyl alcohol, and in particular preferably an ethylene vinyl alcohol with an ethylene content of less than 15 mol%, and preferably of from about 0.1 mol% to about 10 mol%, or from about 10 mol% to about 15 mol%.

[0071] The higher the amount of ethylene in the EVOH is, the higher the water resistance of the polymer is. In freezing environments, where the existence of ice and potential temperature fluctuations may lead to either condensation or the existence of water, a good water resistance is advantageous. Therefore, the water resistance of the corresponding layers of the multilayer barrier structure can ensure the integrity of the package. Furthermore, due to the direct food contact, higher water resistance is also beneficial, as often products contain moisture and it is also paramount to ensure that there is no migration of the polymer into the foodstuff. Having higher ethylene amounts reduces the water solubility of the polymer (and increases the water resistance) thus making it more suited for freezing environments, which is why the polymer may have to be heated for solubilization.

[0072] Furthermore, and in particular for the second barrier layer, when printing might take place, having a higher ethylene content renders the coating more suitable for printing with waterborne inks systems.

[0073] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier agent and second barrier agent is a mixture of a polymer of vinyl alcohol and a copolymer of ethylene and vinyl alcohol, preferably in a weight ratio of between 10:90 to 90:10, of between 20:80 to 80:20 or of between 60:40 to 40:60 based on the total weight of first and second barrier agent, in particular a mixture of polyvinyl alcohol and ethylene vinyl alcohol, preferably in a weight ratio of between 60:40 to 40:60 based on the total weight of first and second barrier agent.

[0074] In another embodiment, when a mixture of a polymer of vinyl alcohol and a copolymer of ethylene and vinyl alcohol is used in the first barrier agent and second barrier agent, the F07341 19.09. 2024

[0075] 13 polymer of vinyl alcohol is comprised in the mixture in an amount of 50% by weight or more, 70 % by weight or more, or 90 % by weight or more, based on the total weight of the polymer of vinyl alcohol and the copolymer of ethylene and vinyl alcohol, in particular when the copolymer of ethylene and vinyl alcohol has a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, more preferably of 98.0 - 99.0 mol% and the polymer of vinyl alcohol has a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, more preferably of 98.0 - 99.0 mol%, and / or in particular, the ethylene vinyl alcohol may have an ethylene content of less than 15 mol%, and preferably of from about 0.1 mol% to about 10 mol%, more preferably of from about 10 mol% to about 15 mol%.

[0076] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier agent and second barrier agent is a mixture of a polymer of vinyl alcohol and a copolymer of ethylene and vinyl alcohol, preferably in a weight ratio of between 10:90 to 90:10, of between 20:80 to 80:20 or of between 60:40 to 40:60 based on the total weight of first and second barrier agent, in particular a mixture of polyvinyl alcohol and ethylene vinyl alcohol, preferably in a weight ratio of between 60:40 to 40:60 based on the total weight of first and second barrier agent, and wherein the copolymer of ethylene and vinyl alcohol has a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, more preferably of 98.0 - 99.0 mol% and the polymer of vinyl alcohol has a saponification level of 95.0 mol% or more, preferably of 98.0 mol% or more, more preferably of 98.0 - 99.0 mol%. In particular, the ethylene vinyl alcohol may have an ethylene content of less than 15 mol%, and preferably of from about 0.1 mol% to about 10 mol%, more preferably of from about 10 mol% to about 15 mol%.

[0077] In one embodiment of the barrier paper according to the first object of the present invention, first barrier layer is located on the rougher side of the base paper layer and the second barrier layer is located on the smoother side of the base paper layer.

[0078] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier layer comprises the first barrier agent in an amount of at least 1.0 gsm (grams per square meter), preferably of at least 2.0 gsm, more preferably of at least 2.5 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25%. In a preferred embodiment, the first barrier layer comprises the first barrier agent in an amount of at least 1 .0 gsm (grams per square meter), preferably of at least 2.0 gsm, more preferably of at least 2.5 gsm, with the proviso F07341 19.09. 2024

[0079] 14 that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25% and no more than 50%, preferably no more than 40%, more preferably no more than 35%.

[0080] The barrier paper according to the first object of the present invention may be preferably manufactured by first coating the smoother side of the base paper layer with the second barrier pre-coat layer and the second barrier layer, drying said layers and then coating the rougher side of the base paper layer with the first barrier pre-coat layer and the first barrier layer and drying said layers, or by first coating the rougher side of the base paper layer with the first barrier pre-coat layer and the first barrier layer, drying said layers and then coating the smoother side of the base paper layer with the second barrier pre-coat layer and the second barrier layer and drying said layers. When the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, the production of the barrier paper is facilitated when first coating the rougher side of the base paper because the heavier barrier layer(s), i.e., the first barrier layer and first barrier pre-coat layer will be dried twice, which ensures thorough drying.

[0081] The composition of the precoats and their amounts (thickness), together with the composition of the barrier agents and their amounts (thickness) ensures synergistic effect of both good barrier performance at frozen conditions and the of ensuring an acceptable moisture level of 5% + / - 1 % when drying. The moisture level within the range ensures that the paper does not block and does not become too brittle.

[0082] In one embodiment of the barrier paper according to the first object of the present invention, the first barrier layer comprises the first barrier agent in an amount of from 2.5 gsm to 3.5 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25% and preferably wherein the second barrier layer comprises the second barrier agent in an amount of from 2.0 gsm to 3.0 gsm. In a preferred embodiment, the first barrier layer comprises the first barrier agent in an amount of from 2.5 gsm to 3.5 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25% and no more than 50%, preferably no more than 40%, more preferably no more than 35% and preferably wherein the second barrier layer comprises the second barrier agent in an amount of from F07341 19.09. 2024

[0083] 15

[0084] 2.0 gsm to 3.0 gsm.

[0085] In one embodiment of the barrier paper according to the first object of the present invention, the binder polymer in the first barrier pre-coat layer is chosen from copolymers of styrene, preferably of copolymers of styrene with butadiene or acrylate (e.g. styrene-butyl acrylate (SBA)), and the pigment in the first barrier pre-coat layer and the second barrier pre-coat layer comprises carbonate minerals such as calcium carbonate or from clay minerals such as talcum or kaolin, or mixtures thereof.

[0086] In one embodiment of the barrier paper according to the first object of the present invention, the binder polymer in the second barrier pre-coat layer is chosen from copolymers of styrene, preferably of copolymers of styrene with butadiene or acryate (styrene-butyl acrylate (SBA)), and the pigment in the first barrier pre-coat layer and the second barrier pre-coat layer comprises carbonate minerals such as calcium carbonate or from clay minerals such as talcum or kaolin, or mixtures thereof.

[0087] In one embodiment of the barrier paper according to the first object of the present invention, the base paper layer has a weight of between 60 and 120 gsm, preferably between 90 and 110 gsm.

[0088] In one embodiment of the barrier paper according to the first object of the present invention, the base paper layer is preferably free of water-insoluble synthetic polymers, in particular is free of impregnating resins such as melamine resins.

[0089] It is a second object of the present invention to provide a process for producing a barrier paper according to the first object of the present invention, comprising the steps of: providing a base paper layer having a rougher side and a smoother side, applying an aqueous first barrier pre-coat composition to the rougher side of the base paper layer and drying the aqueous first barrier pre-coat composition to form a first barrier pre-coat layer, applying an aqueous first barrier composition to the first barrier pre-coat layer and drying the aqueous first barrier layer composition to form a first barrier layer, applying an aqueous second barrier pre-coat composition to the smoother side of the base paper layer and drying the aqueous second barrier pre-coat composition to form a second barrier pre-coat layer, F07341 19.09. 2024

[0090] 16 applying an aqueous second barrier composition to the second barrier pre-coat layer and drying the aqueous second barrier layer composition to form a second barrier layer.

[0091] It is understood that the steps of the above process need not necessarily be carried out in the order in which they appear. For instance, the first barrier pre-coat layer and first barrier layer may be formed prior to the second barrier pre-coat layer and second barrier layer being formed, or the other way around. Alternatively, the first barrier pre-coat layer and second barrier pre-coat layer may be formed first, in any order, and the corresponding barrier layers may then be formed in any order, as well.

[0092] Thus, in an embodiment of the process for producing a barrier paper according to the first object of the present invention, the first barrier pre-coat layer, the first barrier layer, the second barrier pre-coat layer and the second barrier layer may be formed in this order.

[0093] In another embodiment, the second barrier pre-coat layer, the second barrier layer, the first barrier pre-coat layer and the first barrier layer may be formed in this order.

[0094] In another embodiment, the second barrier pre-coat layer, the first barrier pre-coat layer, the first barrier layer and the second barrier layer may be formed in this order.

[0095] In another embodiment, the second barrier pre-coat layer, the first barrier pre-coat layer, the second barrier layer and the first barrier layer may be formed in this order.

[0096] In yet another embodiment, the first barrier pre-coat layer, the second barrier pre-coat layer, the first barrier layer and the second barrier layer may be formed in this order.

[0097] In yet another embodiment more, the first barrier pre-coat layer, the second barrier pre-coat layer, the second barrier layer and the first barrier layer may be formed in this order.

[0098] In general, applying an aqueous first barrier pre-coat composition to the rougher side of the base paper layer and drying the aqueous first barrier pre-coat composition to form a first barrier pre-coat layer may be achieved with a suitable coater, such as a curtain coater, blade coater, roll coated and the like. The blade coater is particularly suited as it produces a flatter surface of the pre-coating, which is beneficial in the subsequent coating step.

[0099] It is understood that the aqueous compositions forming the respective layers will comprise the ingredients recited for the respective layers disclosed above, both qualitatively and F07341 19.09. 2024

[0100] 17 quantitatively.

[0101] For instance, the aqueous first barrier pre-coat composition will comprise the first barrier composition comprising a first barrier agent as recited for the first barrier layer. Analogously, the aqueous first barrier pre-coat composition will comprise the binder polymer and the pigment, preferably where the amount of binder polymer is of from 15 to 50 % by dry weight and the amount of pigment is of from 50 to 85 % by dry weight, and wherein the first barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

[0102] For instance, the aqueous second barrier pre-coat composition will comprise the second barrier composition comprising a second barrier agent as recited for the second barrier layer. Analogously, the aqueous second barrier pre-coat composition will comprise the binder polymer and the pigment, preferably where the amount of binder polymer is of from 15 to 50 % by dry weight and the amount of pigment is of from 50 to 85 % by dry weight and wherein the second barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

[0103] The aqueous first barrier pre-coat composition may have a solids content of more than 50% by weight, and preferably of between 55% and 65% by weight, based on the total weight of the aqueous first barrier pre-coat composition.

[0104] The aqueous second barrier pre-coat composition may have a solids content of more than 50% by weight, and preferably of between 55% and 65% by weight, based on the total weight of the aqueous second barrier pre-coat composition.

[0105] The aqueous first barrier composition may have a solids content of less than 25% by weight, and preferably of between 2% and 20% by weight, preferably between 12% and 18% by weight based on the total weight of the aqueous first barrier composition.

[0106] The aqueous second barrier composition may have a solids content of less than 25% by weight, and preferably of between 2% and 20% by weight, preferably between 12% and 18% by weight based on the total weight of the aqueous second barrier composition.

Claims

F07341 19.

09. 202418CLAIMS1 . A barrier paper for packaging frozen goods, wherein the barrier paper comprises a multilayer barrier structure, comprising, or consisting of, in this order, a first barrier layer comprising a first barrier composition comprising a first barrier agent, a first barrier pre-coat layer, a base paper layer having a rougher side and a smoother side, a second barrier pre-coat layer, a second barrier layer comprising a second barrier composition comprising a second barrier agent, wherein the first barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the first barrier pre-coat layer, wherein the second barrier pre-coat layer comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by weight and the amount of pigment is of from 50 to 85 % by weight, based on the weight of the second barrier pre-coat layer, wherein the first barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more and wherein the second barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

2. The barrier paper according to any one of the preceding claims, wherein the barrier paper does not comprise a metal layer.

3. The barrier paper according to any one of the claims 1 or 2, wherein the first barrier agent and second barrier agent are a copolymer of ethylene and vinyl alcohol.

4. The barrier paper according to any one of the claims 1 or 2, wherein the first barrier agent and second barrier agent are a mixture of a polymer of vinyl alcohol and a copolymer of ethylene and vinyl alcohol, preferably in aF07341 19.

09. 202419 weight ratio of between 10:90 to 90:10, more preferably of between 40:60 and 60:40, based on the total weight of first and second barrier agent.

5. The barrier paper according to any one of the claims 1 or 2 or 4, wherein the first barrier agent and second barrier agent are a mixture of a polymer of vinyl alcohol and a copolymer of ethylene and vinyl alcohol, wherein the copolymer of ethylene and vinyl alcohol has a saponification level of 98.0 - 99.0 mol% and / or ethylene content of less than 15% and the polymer of vinyl alcohol has a saponification level of 98.0 to 98.8 mol%.

6. The barrier paper according to any one of the preceding claims, wherein the first barrier layer is located on the rougher side of the base paper layer and the second barrier layer is located on the smoother side of the base paper layer.

7. The barrier paper according to any one of the preceding claims, wherein the first barrier layer comprises the first barrier agent in an amount of at least 1.0 gsm, preferably of at least 2.0 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25%.

8. The barrier paper according to any one of the preceding claims, wherein the first barrier layer comprises the first barrier agent in an amount of from 2.5 gsm to 3.5 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25% and preferably wherein the second barrier layer comprises the second barrier agent in an amount of from 2.0 gsm to 3.0 gsm.

9. The barrier paper according to any one of the preceding claims, wherein the binder polymer in the first barrier pre-coat layer and the second barrier pre-coat layer is chosen from copolymers of styrene, preferably of copolymers of styrene with butadiene or acrylate, and in the first barrier precoat layer and the second barrier pre-coat layer comprises the pigmentF07341 19.

09. 202420 chosen from carbonate minerals such as calcium carbonate or from clay minerals such as talcum or kaolin, or any mixture thereof.

10. The barrier paper according to any one of the preceding claims, wherein the base paper layer has a weight of between 60 and 120 gsm, preferably between 90 and 110 gsm and / or wherein the base paper layer is free of water-insoluble synthetic polymer.11 . A process for producing a barrier paper according to any one claim 1 to 10, comprising the steps of: providing a base paper layer having a rougher side and a smoother side, applying an aqueous first barrier pre-coat composition to the rougher side of the base paper layer and drying the aqueous first barrier pre-coat composition to form a first barrier pre-coat layer, applying an aqueous first barrier composition to the first barrier pre-coat layer and drying the aqueous first barrier layer composition to form a first barrier layer, applying an aqueous second barrier pre-coat composition to the smoother side of the base paper layer and drying the aqueous second barrier pre-coat composition to form a second barrier pre-coat layer, applying an aqueous second barrier composition to the second barrier precoat layer and drying the aqueous second barrier layer composition to form a second barrier layer.

12. The process for producing a barrier paper according to claim 11 , wherein the aqueous first barrier composition comprises a first barrier agent and the aqueous first barrier pre-coat composition comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by dry weight and the amount of pigment is of from 50 to 85 % by dry weight, and wherein the first barrier agent comprises or consist of a water- soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

13. The process for producing a barrier paper according to claim 11 or 12, wherein the aqueous second barrier composition comprises a secondF07341 19.

09. 202421 barrier agent and the aqueous second barrier pre-coat composition comprises a binder polymer and a pigment, preferably where the amount of binder polymer is of from 15 to 50 % by dry weight and the amount of pigment is of from 50 to 85 % by dry weight, and wherein the second barrier agent comprises or consist of a water-soluble polymer of vinyl alcohol or a water-soluble copolymer of vinyl alcohol, or mixtures thereof, having a saponification level of 95.0 mol% or more.

14. The process for producing a barrier paper according to claim 11 , 12 or 13, wherein the aqueous first barrier composition comprises the first barrier agent and the barrier agent is applied in an amount of at least 1.0 gsm, preferably of at least 2.0 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25%.

15. The process for producing a barrier paper according to claim 11 , 12, 13 or 14, wherein the aqueous second barrier composition comprises the second barrier agent and is applied in an amount of from 2.5 gsm to 3.5 gsm, with the proviso that the amount of the first barrier agent is higher than the amount of second barrier agent in the second barrier layer, preferably by at least 15%, more preferably by at least 20%, most preferably by at least 25% and preferably wherein the second barrier layer comprises the second barrier agent and the barrier agent is applied in an amount of from 2.0 gsm to 3.0 gsm.