Barrier Paper

Abstract

The present invention relates to - Base paper and - at least one coating color layer S1 applied directly or indirectly to said base paper, at least one barrier layer B1 applied directly or indirectly to said coating color layer S1, - a coating B2 applied directly or indirectly to said barrier layer B1; The present invention relates to a barrier paper comprising:

Description

[Technical field]

[0001] The present invention relates to a barrier paper, a method for producing such a barrier paper, the use of the barrier paper as a packaging material, and packaging comprising the barrier paper. [Background technology]

[0002] Packaging generally refers to a covering or wrapping (partial or complete) of an object, more specifically a covering or wrapping (partial or complete) for its protection or better handling. Packaging material therefore includes materials that form such packaging.

[0003] The packaging material may be composed of, for example, paper, plastic, and / or metal. The present invention deals with paper-based packaging materials.

[0004] Whatever its origin, the main requirement of a packaging material is to protect the packaged goods from external influences and to prevent leakage of the packaged goods. For this purpose, the packaging material should meet different criteria depending on the packaged goods and the packaging process. That is, in addition to so-called barrier properties, for example against water, fat, oxygen or mineral oil, suitable packaging materials should also meet mechanical and process-specific requirements. Depending on the packaging system, the packaging material should have sufficient tear resistance, a suitable coefficient of friction (friction value) and flexibility, should be sealable, more specifically heat-sealable, and compatible with ultrasonic or cold-seal adhesives, as well as printable from the outside, and should not lose its protective effect during the entire conversion and packaging process.

[0005] Depending on its composition and basis weight, paper can meet many mechanical requirements but, due to its physical properties and porous structure, may require additional coatings to provide, for example, heat sealability or a barrier.

[0006] Known paper-based coated packaging materials often contain compounds such as polyvinylidene chloride (containing halogens) or are composites of paper and plastic films, have improvable tear resistance that can lead to running problems in the packaging system, and / or are often non-recyclable due to excessively high coating content, adhesive components, optical inhomogeneity, or the formation of so-called adhesive impurities (stickies) through the paper fiber stream, and / or are not sufficiently resistant to buckling due to their metallic surface coating, and / or are not effective in high humidity environments due to their respective polymers. Furthermore, coating via vacuum deposition typically requires a particularly smooth and chemically suitable surface, which is typically formed using a precoat.

[0007] Polyvinyl alcohol is also widely known as a linear water-soluble, biodegradable barrier coating for paper. Such coatings exhibit good barrier properties against oil, grease, oxygen, solvents and other non-polar gases, liquids or solids. However, due to its hydrophilic nature, polyvinyl alcohol is highly permeable to polar compounds such as water. Since polyvinyl alcohol absorbs moisture very well and swells, thus forming pathways through the barrier coating at the molecular level, this may also affect the barrier effect against non-polar migrating substances.

[0008] Many attempts have been made to achieve barrier reduction above 50 or 60% relative humidity, for example by adding pigments as disclosed in WO2010 / 129032, or by crosslinking the polymer chains as disclosed in WO2020 / 109401 or US 6,444,750. However, it is not only these microscopic defects that are detrimental to the use of polyvinyl alcohol as a barrier, but the occurrence of macroscopic defects due to mechanical stresses in packaging and conversion systems also and especially impairs the scope of use of polyvinyl alcohol.

[0009] Polyvinyl alcohol is understood as fully saponified polyvinyl acetate, which is a (thermoplastic) plastic of formula (I) below, usually synthesized by means of the radical polymerization of vinyl acetate.

[0010] [ka]

[0011] The ester groups of polyvinyl acetate are relatively easily saponified under alkaline conditions, converting the polyvinyl acetate into polyvinyl alcohol, which becomes hydrophilic and water sensitive.

[0012] Partially saponified polyvinyl acetate is also known as partially saponified polyvinyl alcohol.

[0013] In the present invention, the term partially saponified polyvinyl acetate may be used synonymously with the term partially saponified polyvinyl alcohol.

[0014] The degree of saponification indicates the proportion of ester groups that have been saponified and are no longer present as -OH groups. For example, a polyvinyl alcohol with a degree of saponification of 90% is a vinyl acetate polymer in which 90% of the original ester groups have been saponified. Thus, this polyvinyl alcohol contains 90% OH groups and 10% ester groups. At a degree of saponification of 100%, all of the original ester groups have been saponified, so that only OH groups are present.

[0015] In addition to the pure homopolymers, many copolymers of polyvinyl alcohol are also of great technological importance. The copolymers are all polymers consisting mainly (more than 50%) of vinyl alcohol or vinyl acetate units, regardless of the number of different monomers used in their synthesis.

[0016] Such polyvinyl alcohol copolymers preferably include polyethylene vinyl alcohol.

[0017] In a narrower sense, saponification herein refers to the hydrolysis of esters with aqueous solutions of hydroxides, such as sodium hydroxide, or with special enzymes (esterases). In contrast to acidic ester hydrolysis (the reverse reaction of esterification), they are irreversible, since the protons required for esterification are lost from the carboxylic acid. The products of the reaction are alcohols and salts of the acids (carboxylation), from which the esters are composed. In a broader sense, any hydrolysis of an ester can be described as saponification.

[0018] Additionally, 5g / m at 38°C and 90% relative humidity 2 Metallized barrier papers having a low water vapor transmission rate (WVTR) of less than 1 / d are already known, for example from document WO2021 / 023661A1.

[0019] From document WO2021 / 251449A1, a paper substrate for metal deposition is known, which comprises a base paper and a layer comprising a polyvinyl alcohol resin on the base paper. Preferably, the paper substrate comprises a further layer comprising a water vapor barrier resin as a filler layer, which preferably contains a platelet-shaped pigment. Examples of metal deposition layers include aluminum, tin, nickel, copper, gold, platinum, silver, cobalt, chromium, etc., with aluminum being preferred due to its high light-shielding properties and low cost.

[0020] WO2021 / 260043A1 also describes a metallizable barrier paper. Summary of the Invention [Problem to be solved by the invention]

[0021] The object of the present invention is to eliminate the drawbacks of known materials and to provide a material that is suitable as a packaging material, especially for moisture- and oxidation-sensitive and fatty foods, and that can be used to manufacture packaging such as tubular bags using heat-sealing or cold-sealing processes. Moreover, the material should not contain any barrier layer based on halogen-containing compounds. Furthermore, the material according to the present invention should have one or more of the following properties compared to known packaging materials:

[0022] The barrier paper should have improved oxygen barrier, improved grease barrier, improved mineral oil barrier, improved buckling resistance and flexibility (equivalent to no or minimal loss of barrier properties due to buckling or bending of the barrier paper or packaging made from the barrier paper), recyclability through the waste paper cycle, improved heat seal properties, improved cold seal properties (compatible with sealing media, e.g. water-based cold seal adhesives, etc.), high tear resistance, no alteration of the taste of the contents of the package, exhibit aroma sealability, and be printable on the outside and inside. The material should also have an improved water vapor barrier and the sealing seams should be as moisture resistant as possible. Finally, the material should be as economically manufacturable as possible.

[0023] Furthermore, it is an object of the present invention to further improve the application properties of metallized barrier paper, to find methods for the production of improved barrier papers, and to indicate their uses. [Means for solving the problem]

[0024] This object is achieved by a barrier paper according to claim 1 having the following features: at least - Base paper and - at least one coating color layer S1 applied directly or indirectly to said base paper, at least one barrier layer B1 applied directly or indirectly to said coating color layer S1, - a coating B2 applied directly or indirectly to said barrier layer B1; Provided is a barrier paper.

[0025] Surprisingly, it has been found that the inventive structure of such a barrier paper can decisively improve its application properties. In particular, it was possible to achieve at least comparable properties as an environmentally friendly and sustainable substitute for plastic packaging for consumer goods and food, while preserving the excellent recyclability properties of the paper packaging, in particular in the waste paper cycle. In addition to the arrangement of the coating color layer S1, its properties are particularly important both for the subsequent barrier layer B1 and for the properties of the barrier paper as a flexible packaging material.

[0026] The barrier paper according to the invention can be used without any problems in common packaging machines for plastic packaging, where common packaging, e.g. heat sealed tubular bags for sensitive foodstuffs such as chips and chocolates, or ultrasonically sealed inner liners for tobacco products, can be formed and sealed sufficiently tightly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In the following, reference is made to preferred embodiments of the barrier paper according to the invention.

[0028] Preferably, said coating color layer S1 has the following properties: a) water vapor barrier; b) oxygen barrier; c) a mineral oil barrier; d) Oil barrier e) odor barrier; f) buckling resistance of at least one property; g) Grease resistance; h) Sealing performance i) Beck smoothness of at least 200 Beck seconds The barrier paper has at least one of the following properties:

[0029] The grease resistance of the barrier paper according to the invention according to the palm kernel fat test has in particular at least one of the following values ​​listed under a) to f) (number of penetrations with a diameter of less than 1 mm / number of penetrations with a diameter of more than 1 mm): a) Display paper (AP): less than 5 / 5, preferably less than 2 / 2, in particular 0 / 0 b) Test paper (PP): less than 5 / less than 5, preferably less than 2 / less than 2, in particular 0 / 0 c) Display paper (AP) - Inner bending: less than 5 / 5, preferably less than 2 / 2, in particular 0 / 0 d) Test paper (PP) - Inner bending: less than 5 / less than 5, preferably less than 2 / less than 2, in particular 0 / 0 e) Display paper (AP) - Outer bending: less than 5 / 5, preferably less than 2 / 2, in particular 0 / 0 f) Test paper (PP) - Outer bending: less than 5 / less than 5, preferably less than 2 / less than 2, in particular 0 / 0

[0030] Palm kernel fat test: similar to DIN 53116. For bent specimens, a 180° bend is produced by a roller that applies a load of 330 g / cm to the resulting bend, and the coating can be on the inside (inner bend) or outside (outer bend).

[0031] Indicator paper: Evaluation of the indicator paper referred to in DIN 53116. For this, fat penetration points with a diameter (d) of less than 1 mm (first value in the table) and more than 1 mm (second value in the table) are counted.

[0032] Test paper: Evaluation of the reverse side of the test paper as mentioned in DIN 53116. This is not part of the standard but was done for better differentiation.

[0033] A barrier paper, the coating colour layer S1 of which comprises or consists of at least one water-soluble and / or water-dispersible polymer.

[0034] Preferably, the at least one water-soluble polymer and / or the at least one water-dispersible polymer is a) polyvinyl alcohol, in particular partially or fully saponified polyvinyl alcohol; b) polyvinyl alcohol copolymers, in particular partially or completely saponified polyvinyl alcohol copolymers copolymerized with ethylene, polyvinylamine, acrylic acid derivatives; c) modified fully or partially saponified polyvinyl alcohols or copolymers, in particular with acyl, alkyl, acrylamide, silanol, diacetone, acetoacetyl, itaconic acid modifications; d) a polymer having an onset temperature of less than 210°C as determined by DSC; e) acrylic-based polymers; f) polyester-based polymers; g) nitrocellulose-based polymers; h) Polyvinyl acetate based polymers The barrier paper is selected from the group consisting of:

[0035] In the context of this disclosure, unless otherwise specified, the onset temperature is determined by DSC according to DIN EN ISO11357-1:2010-03 as the intersection of the extrapolated baseline and the tangent to the inflection point at the onset of the melting or crystallization peak.

[0036] Thus, in particular in the case of polymers selected from this group, the barrier layer B1 can be applied directly to the coating color layer, i.e. for example without an intermediate layer, without adhesion promoters or pretreatment of the coating color layer, for example with corona or plasma treatment.

[0037] Furthermore, due to the particular suitability of polyvinyl alcohol, it is possible to easily and reliably apply the barrier layer B1, in particular the metallization, while eliminating a precoat.

[0038] Preferred is a barrier paper, wherein said at least one water-soluble polymer and / or said at least one water-dispersible polymer comprises an at least partially saponified polyvinyl alcohol and / or an at least partially saponified polyvinyl alcohol copolymer, respectively, having an onset temperature of less than 210° C., determined by DSC.

[0039] Preferred is a barrier paper, wherein the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification between 30% and 95%, an average molecular weight between 0 g / mol and 100,000 g / mol, and an onset temperature determined by DSC below 200°C.

[0040] Preferred is a barrier paper, wherein said at least one water-soluble polymer and / or said at least one water-dispersible polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification of more than 95% to 100%, an average molecular weight of more than 70,000 g / mol and an onset temperature determined by DSC of less than 200° C.

[0041] Preferred is a barrier paper, wherein said at least one polymer comprises a partially saponified polyvinyl alcohol copolymer, preferably a partially saponified polyethylene vinyl alcohol, having a degree of saponification between 95% and 100%, an average molecular weight of more than 60,000 g / mol and an onset temperature determined by DSC of less than 210° C.

[0042] Preference is given to barrier papers in which the partially saponified polyvinyl alcohol and / or the partially saponified polyvinyl alcohol copolymer has a viscosity at a dry content of 4% of less than 30 mPas, particularly preferably less than 20 mPas, most particularly preferably less than 15 mPas.

[0043] Preferred is a barrier paper, wherein said at least one polymer comprises a mixture of water-soluble and / or water-dispersible polymers mentioned as preferred above.

[0044] Preferably, said coating colour layer S1 is a barrier paper having a surface tension in the range of 25 to 80 mN / m, in particular 25 to 75 mN / m. A particularly preferred range is 45 to 70 mN / m. Preferably, the polar part of the surface tension is in the range of 55 to 80%.

[0045] These surface tensions (surface energies) are particularly advantageous for the direct application of the barrier layer B1, especially during metallization (wetting, nucleation, growth). Conventional coatings, for example based on BOPP or PET, must first be treated, for example using corona plasma, to achieve a surface tension of at least 25 mN / m, preferably at least 35 mN / m.

[0046] Polyvinyl alcohol is suitable as a preferred polymer for the coating color layer S1 due to its high surface tension (surface energy) of about 50-70 mN / m, which also contains a particularly high polar fraction of about 70-80%, so that particularly thin metal layers have a significantly lower and predominantly dispersed surface tension. For example, for a polyvinyl alcohol-based coating color layer S1 on which Al was deposited using physical vapor deposition, a surface tension of 27.6 mN / m was measured with a polar fraction of only 3.6%. Pure aluminum has an extremely high surface tension of 1200 mN / m. In reality, aluminum is coated with an oxide layer, resulting in a surface tension of about 40 mN / m. As a result, the metal layer (barrier layer B1) does not just adhere via weak forces as it does to most non-polar plastics (polyolefins, polyesters, acrylic copolymers, etc.), but is more firmly anchored, which results in higher composite strength, which is also obviously an advantage when bending the barrier paper, since the metal layer (barrier layer B1) does not peel off during bending, even in the more demanding case of outer bending.

[0047] Furthermore, there are other preferred water-soluble and therefore polar polymers with a certain oxygen barrier, which are particularly suitable for the coating color layer S1 as well as for the coating B2. Polymers that may be mentioned are natural and modified starches, partially degraded starches, modified soluble cellulose, nanocellulose and other polymeric carbohydrates, such as chitosan, pullulan, curdlan, xanthan gum, hemicellulose, pectin, dextran, acacia gum, karaya, guar gum, gellan gum, etc. Since many carbohydrates tend to be brittle, it is desirable to add smaller molecules that act as plasticizers in hydrophilic polymers. Examples include sugar alcohols, such as glycerol and sorbitol, poly(ethylene) glycol. Other natural polymers that may be used are proteins, such as casein, corn zein, keratin, collagen, gelatin, whey protein, wheat gluten, rapeseed protein, soy protein, kafirin, oat avenin, rice bran protein, lupin protein, cotton protein, or peanut protein. Water insoluble polymers may also be used, particularly those that do not form an oxygen barrier but do form a barrier to fat and mineral oil vapors. These also have high, primarily polar, surface energies.

[0048] Pigments that improve the barrier effect can also be added to all these polymers mentioned. However, care must then be taken to ensure that they do not significantly impair the smoothness of the layers. This can be achieved by choosing platelet-shaped pigments with a high shape factor (aspect ratio), the thickness of which is less than that of the layers, and whose proportion does not exceed 50% (w / w) of the layers. Examples of such pigments are kaolin, natural and synthetic phyllosilicates (mica), talc, precipitated Ca carbonate.

[0049] The coating color layer S1 may be applied to one or both sides of the base paper. Several coating color layers S1 may be arranged on one side of the base paper, in particular the composition or layer thickness or even the basis weight may be the same or different. The coating B2 and the coating color layer S1 may be the same or different, in particular the composition or layer thickness or even the basis weight may be the same or different.

[0050] Preference is given to a barrier paper, wherein the barrier layer B1 comprises or consists of a metal, in particular Al, Cu, Sn, Zn, Ag, Au, Ti, In, Si, a metal alloy, a metal oxide, in particular Al2O3, SiO2, mixed oxides or combinations thereof.

[0051] Preferred barrier papers are those in which the barrier layer B1 is applied using vacuum deposition or other known or conventional processes.

[0052] Preferably, said barrier layer B1 has the following features: a) an optical density of 1.5 or greater and 6.0 or less; b) A barrier paper having at least one of the layer thicknesses of 5 nm or more, preferably 10 nm or more, particularly preferably 15 nm or more, in particular 5 nm to 150 nm.

[0053] The barrier layer B1 may be applied to one or both sides of the base paper. Several barrier layers B1 may be arranged on one side of the base paper, in particular with the same or different composition or layer thickness.

[0054] Preferably, said coating B2 comprises at least one polymer, in particular a) polyethylene acrylic acid copolymer, b) polyolefins, c) polyvinyl alcohol, d) cellulose nitrate, e) bio-based polymers; f) non-biobased polymers; g) styrene-butadiene latex, h) Acrylate latex The barrier paper comprises or consists of a polymer selected from the group consisting of:

[0055] Preferably, said coating B2 has the following properties: a) protection of the barrier layer B1 against external influences, in particular mechanical influences, such as buckling in the packaging system when closing the package (e.g. sealing seal) or when rubbing, or against chemical influences, b) Sealing properties, especially high temperature, ultrasonic and cold sealing properties; c) Grease resistance; d) water resistance; e) Moisture resistance, f) printability; g) additional barrier properties; h) Optimization of existing barrier properties The barrier paper has at least one of the following properties:

[0056] Preferred features are: a) 5g / m at 23°C and 50% relative humidity 2 WVTR below / d, b) 5g / m at 23°C and 50% relative humidity 2 WVTR (medial flexion) below / d, c) 5g / m at 23°C and 50% relative humidity 2 WVTR (lateral flexion) below / d, d) 15 g / m at 38°C and 90% relative humidity 2 WVTR below / d, e) 15 g / m at 38°C and 90% relative humidity 2 WVTR (medial flexion) below / d, f) 15g / m at 38°C and 90% relative humidity 2 WVTR (lateral flexion) below / d, g) 10 cm at 23°C and 50% relative humidity 3 / m 2 OTR below / d, h) 10 cm at 23°C and 50% relative humidity 3 / m 2 / d or less OTR (medial flexion), i) 10 cm at 23°C and 50% relative humidity 3 / m 2 OTR (outward bending) less than / d, j) Buckling resistance of at least one barrier property, especially in the region of inward bending and / or outward bending; k) a residual moisture content of at least 2.5% (w / w), in particular at least 3.0% (w / w), based on the total weight of the barrier paper; The barrier paper has at least one of the following properties:

[0057] Preferred features are: a) 3g / m at 23°C and 50% relative humidity 2 WVTR below / d, b) 3 g / m at 23°C and 50% relative humidity 2 WVTR (medial flexion) below / d, c) 3 g / m at 23°C and 50% relative humidity 2 WVTR (lateral flexion) below / d, d) 10 g / m at 38°C and 90% relative humidity 2 WVTR below / d, e) 10 g / m at 38°C and 90% relative humidity 2 WVTR (medial flexion) below / d, f) 10g / m at 38°C and 90% relative humidity 2 WVTR (lateral flexion) below / d, g) 510 cm at 23°C and 50% relative humidity 3 / m 2 OTR below / d, h) 5cm at 23°C and 50% relative humidity 3 / m 2 / d or less OTR (medial flexion), i) 5cm at 23°C and 50% relative humidity 3 / m 2 OTR (outward bending) less than / d, j) Buckling resistance of at least one barrier property, especially in the region of inward bending and / or outward bending; k) a residual moisture content of at least 2.5% (w / w), in particular at least 3.0% (w / w), based on the total weight of the barrier paper; The barrier paper has at least one of the following properties:

[0058] Buckling resistance of at least one barrier property, in particular in the region of an inward or outward bend, means that in the region of the bend or bend, the at least one barrier property deviates from the barrier property of the barrier paper by no more than 100%, preferably no more than 75%, particularly preferably no more than 50% and very particularly preferably no more than 25%. For example, a barrier paper according to the invention has a measured WVTR of 1.5 g / m 2 / d (38°C and 90% relative humidity), the WVTR measurements in the area of ​​the inner bend (i.e. the inner bend is within the measurement surface) or directly at the inner bend should be between 0 and 3 g / m 2 / d (less than 100% maximum).

[0059] Preference is given to barrier papers in which said coating colour layer S1, said barrier coating B1 and said barrier coating B2 are removable in the waste paper cycle.

[0060] Preference is given to a print that, after reprocessing according to INGEDE method 11, has the following score according to the Assessment of Printed Product Recyclability, Deinkability Score: a) Lightness Y up to 35 points, b) Color coefficients in the CIELAB system up to 20 points a * , c) Soil stains A in two different size classes, A50 up to 15 points and A250 up to 10 points; d) the degree of dye removal (ink removal) IE up to 10 points, and e) Darkening of the filtrate ΔY up to 10 points; wherein the sum of all points is in the range of 0 to 100, preferably in the range of 51 to 70, more preferably in the range of 71 to 100, and / or preferably each individual point value is non-negative.

[0061] Preference is given to a barrier paper in which a precoat is present between the base paper and the coating colour layer S1, comprising at least one inorganic pigment and a polymeric binder, the inorganic pigment being preferably platelet-like and preferably comprising talc, precipitated calcium carbonate, a silicate, preferably a phyllosilicate or kaolin, and / or the polymeric binder comprising a polyacrylate-based polymeric binder.

[0062] Preferably, the precoat comprises at least one polymeric binder, at least one organic and / or one inorganic pigment, and optionally the usual amounts of further coating coloring components. Pigment: phyllosilicate. Polymer binder: styrene acrylate latex, butadiene latex. Rheology modifiers, such as acrylate-based thickeners and / or zirconium-based crosslinkers.

[0063] It is preferred that the basis weight of said coating color layer S1 and said coating B2 is between 4 and 20 g / m2, based on the dry final product (air dried). 2 , preferably 8 to 15 g / m 2 It is a barrier paper that is within the range.

[0064] Preferred is a barrier paper that is free of halogen-containing compounds, except for unavoidable trace elements.

[0065] It is preferable that the base paper has a thickness of 20 to 120 g / m 2 , preferably 40 to 100 g / m 2 is a barrier paper having a basis weight of

[0066] Preferred is a barrier paper, wherein the base paper has a long fiber content of 10-80% and a short fiber content of 20-90% (w / w), the long fibers having a fiber length of 2.6-4.4 mm and the short fibers having a fiber length of 0.7-2.2 mm.

[0067] Preferred is a barrier paper, wherein the base paper comprises or consists of 100% virgin fiber pulp and up to 100% recycled fibers, or a blend of both.

[0068] Preferably, the base paper is a barrier paper containing up to 90% recycled fibres.

[0069] Preference is given to base papers which have a starch precoat or a starch-containing precoat, preferably on one or both sides, in particular to improve printability.

[0070] The invention further relates to a method for producing a barrier paper, characterized in that an aqueous suspension comprising the starting material for the coating colour layer S1 is applied indirectly or directly to the base paper, said aqueous coating suspension having a solids content of 5-50% by weight, preferably 10-30% by weight, and is applied by a curtain coating process, preferably a double curtain coating process, at an operating speed of the coating plant of at least 200 m / min.

[0071] Preferably, after normal drying of the coating colour layer S1, the barrier paper is re-moistened by means of a moistening unit or steam blowing box to achieve a moisture content of 2.5-7%, preferably 3.5-5%, particularly preferably 4-4.5%, based on the total weight. This is ideal for barrier coatings B1, in particular when metallization is involved, to maintain the flexibility of the coating colour layer S1 and the base paper, but also to prevent excess moisture from entering the coating chamber (e.g. vacuum chamber).

[0072] Preferably, after the usual rewetting of the coating colour layer S1, the barrier paper is rewetted by means of a moistening unit or steam blowing box to achieve a moisture content of 2.5 to 7%, preferably 3.5 to 5%, particularly preferably 4 to 4.5%, based on the total weight.

[0073] Preferably, after normal rewetting of the coating colour layer S1, the surface of the coating colour layer S1 is smoothed / satin finished using one or more roller smoothing units, gloss finishing calenders or shoe calenders to a smoothness of at least 200 Bekk seconds, in particular 500 Bekk seconds.

[0074] Preferably, after the usual smoothing of the coating colour layer S1, the barrier layer B1 is applied directly or indirectly to the coating colour layer S1 using conventional methods.

[0075] Coating B2 may then be applied directly or indirectly to barrier layer B1 using conventional methods and optionally dried using conventional methods.

[0076] Following coating B2, a full surface or partial seal lacquer, in particular a heat seal lacquer or a cold seal lacquer, may be applied directly or indirectly to coating B2 and / or to the opposite outer surface of the barrier paper using conventional processes and may be dried directly or indirectly using conventional processes.

[0077] Following coating B2, full surface or partial printing may be applied directly or indirectly to coating B2 or the opposite exterior surface using conventional processes to render the package recognizable and to provide information, and may be dried directly or indirectly using conventional processes.

[0078] The invention also relates to the use of a barrier paper according to the invention, or a barrier paper produced according to the method, as packaging material for food, consumer goods, tobacco products or as a component of packaging material, in particular corrugated or cardboard-based packaging material, in particular as packaging material for food, in particular sausages, cheese, coffee, muesli bars, chocolate, chocolate-containing products or chips.

[0079] The present invention also relates to a packaging comprising a barrier paper or a barrier paper produced according to the method according to the invention, which is preferably a cold sealed packaging, a heat sealed packaging, an ultrasonic sealed packaging, in particular a tubular bag packaging.

[0080] In a preferred embodiment, the coated side of the packaging (the inner side) faces inwards (the inner side of the packaging) and the outer side faces outwards. This allows, in particular, the packaging of wet and / or greasy goods, where the outer side is printed and the inner side is sealed to the inner side (A:A seal) and / or the inner side is sealed to the outer side (A:B seal).

[0081] In particular, there are packaging embodiments in which the coated side (inner side) faces the outside (outer side of the packaging) and the outer side faces the inside. This makes it possible to protect particularly moisture-sensitive packages from drying out. In this case, the inner side is printed and the outer side is sealed to the outer side (A:A seal) and / or the outer side is sealed to the inner side (A:B seal).

[0082] The quality of the barrier paper according to the invention, in particular with regard to its buckling resistance, can be determined, among other methods, by dynamic mechanical thermal analysis (DMTA).

[0083] Dynamic mechanical thermal analysis (DMTA) / DMTA measurement: Dynamic Mechanical Thermal Analysis (DMTA) is a method for measuring the viscoelastic properties of a polymer or material system. By applying a cyclic sinusoidal stress / strain force to induce deformation without destruction, the sinusoidal response of the material can be shifted and the phase angle calculated. The phase angle of a viscoelastic material is defined as being greater than 0° (purely elastic material) and less than 90° (purely viscous material). The tangent value is therefore the ratio between the elastic modulus (G') and the viscous modulus (G") given by the following equation:

[0084]

number

[0085] The tan values ​​(quantified loss damping effect), elastic modulus (G') and viscous modulus (G") of a packaging material that retains its barrier properties after buckling or bending can be compared to packaging materials that lose their intended barrier properties. We obtained the tan of the material that retains its barrier properties after buckling or bending, and the tan of the material that loses its barrier properties after bending. The tan (loss factor) is within the range accepted for viscoelastic materials (tan=0-1.0).

[0086] The barrier paper according to the invention is further preferably characterised in that the value of loss factor tan delta of said barrier paper, measured as a function of temperature using Dynamic Mechanical Thermal Analysis (DMTA), passes through a maximum value at a temperature Tg and a first inflection point at a temperature Tw with increasing temperature.

[0087] Here, the temperature Tg is preferably lower than the temperature Tw.

[0088] Barrier papers having a value of the loss factor tan delta, measured as a function of temperature, which with increasing temperature passes through a maximum value at a temperature Tg and a first inflection point at a temperature Tw, preferably with Tg lower than Tw, are characterized in that they retain their barrier properties in an advantageous manner after buckling.

[0089] Preferably, the amount of difference between tan delta at temperature Tg and tan delta at temperature Tw is greater than 0.013, preferably greater than 0.014, particularly preferably greater than 0.015.

[0090] In particular, at such values ​​of the difference between tan delta at temperature Tg and tan delta at temperature Tw, the barrier properties are advantageously maintained after buckling.

[0091] As explained above, the onset temperature is determined using DSC as follows:

[0092] The (extrapolated) onset temperature (according to DIN EN ISO11357-1:2010-03) is the intersection of the extrapolated baseline and the inflection tangent at the beginning of the melting or crystallization peak in a DSC measurement. The baseline and the inflection tangent are determined from the temperature-dependent heat flow signal. For pure, homogeneous materials, the initial temperature can be designated as the melting temperature. In contrast to the peak temperature, the onset temperature is less dependent on the heating rate and the sample mass. Furthermore, the onset temperature is usually used to calibrate the temperature of the DSC.

[0093] The barrier paper according to the invention is characterized in that it is particularly suitable as packaging material for moisture- and oxidation-sensitive and greasy objects, especially foodstuffs, and can be used to manufacture pouches by heat-sealing or cold-sealing applications, water-based cold-sealing adhesives can be used for the cold-sealing application, and furthermore no layer based on a halogen-containing compound or barrier layer needs to be present.

[0094] Partially saponified polyvinyl alcohol has an advantage over fully saponified polyvinyl alcohol (PVOH) or polyethylene vinyl alcohol (EVOH) in that it has a significantly lower optimum sealing temperature in the heat sealing process. This has no adverse effect on the strength of the sealed seam. Furthermore, partially saponified polyvinyl alcohol has a slightly lower viscosity at otherwise the same concentration. High viscosity is somewhat disadvantageous, since in this case the PVOH solution needs to be more diluted, and therefore more water needs to be dried in the coating process. This not only requires energy and therefore a coating system with a higher drying capacity, but depending on the desired application weight, can be difficult to realize in terms of application technology. Furthermore, the diffusion of water molecules at high viscosity, and thus the drying itself, slows down. Furthermore, the accumulation of gaseous water in the coating is more likely to occur, leading to the formation of macroscopic coating defects.

[0095] Thus, partially saponified polyvinyl alcohol or partially saponified polyvinyl alcohol copolymers, such as polyethylene vinyl alcohol, are preferred over the fully saponified variants.

[0096] In particular, for example, in the case of water- and moisture-sensitive coatings, color layers S1, based on polyvinyl alcohol, these must be protected from a moist environment. This can be achieved by vacuum deposition of metals with minimal application. Vacuum deposition also requires a high degree of smoothness or minimal roughness.

[0097] Due to its minimal thickness, the vacuum-deposited layer must on the one hand be protected against scratches, abrasion, oxidation and destruction. Moreover, in order to produce pouches or similar packaging forms, an additional sealing layer is necessary in certain packaging manufacturing processes. This is achieved by applying coating B2 to barrier layer B1 (e.g. vacuum-deposited layer). Moreover, coating B2 may further improve the oxygen or water vapor barrier.

[0098] The barrier paper according to the present invention is also characterized by an improved oxygen barrier, an improved grease barrier, an improved mineral oil barrier, and an improved water vapor barrier.

[0099] The barrier paper according to the invention further has an improved resistance to buckling without compromising the barrier effect and is furthermore characterised by high resistance to tearing.

[0100] Furthermore, the barrier paper according to the present invention is recyclable through the waste paper cycle.

[0101] When the barrier paper according to the invention is used as packaging material for food, the barrier paper is particularly characterized in that it does not affect and / or change the taste of the packaged food.

[0102] Furthermore, the barrier paper according to the invention is heat sealable, exhibits improved cold seal properties (compatible with sealing media such as water-based cold seal adhesives), and each sealing seam exhibits sufficient moisture resistance.

[0103] Furthermore, the barrier paper according to the present invention is easily printed on the uncoated side (outside) and on the coated side (inside).

[0104] Finally, the barrier paper according to the invention can be manufactured relatively easily and with low coating weights, and can be recycled through the waste paper cycle.

[0105] Hereinafter, the term "comprise" can also mean "consisting of".

[0106] A material is described as "hydrophobic" if it cannot be mixed with water or can only be wetted by water with the use of a surfactant. A material is described as "hydrophilic" if it can be mixed with water or can be wetted by water without the use of a surfactant. Hydrophobic polymers are also known as non-polar polymers, and hydrophilic polymers are also known as polar polymers.

[0107] Hydrophobicity or hydrophilicity can be defined, for example, using the logP value. The n-octanol / water partition coefficient K ow (also commonly and correctly spelled octanol / water partition coefficient) is a dimensionless partition coefficient known to those skilled in the art that indicates the ratio of the concentration of a chemical in a two-phase system of n-octanol and water and is therefore a measure of the hydrophobicity or hydrophilicity of a substance. The logP value is the n-octanol-water partition coefficient K ow The following holds:

[0108]

number

[0109] c o Si = concentration of chemical in the octanol-rich phase, c w Si = concentration of chemical in the water-rich phase.

[0110] K ow is greater than 1 if the substance is more soluble in a fat-like solvent such as n-octanol and less than 1 if the substance is more soluble in water. Thus, logP is positive for hydrophobic / lipophilic substances and negative for hydrophilic / lipophobic substances.

[0111] The low permeability of polyvinyl alcohol to oxygen, mineral oil, grease, and other non-polar migrating substances is due to its relatively high hydrophilicity.

[0112] Furthermore, polymers containing ethylene, such as (saponified) polyethylene vinyl alcohol, have lower water vapor permeability due to the ethylene content and the associated lower hydrophilicity.

[0113] In principle, the base paper used for the coated paper according to the invention is not limited.

[0114] However, the base paper is 20 to 120 g / m 2 , preferably 40 to 100 g / m 2 It is preferred that the sheet has a basis weight of 1000 g.

[0115] Furthermore, it is preferred that the base paper has a composition having a long fiber content of 10-80% (w / w), preferably 20-50% (w / w), and a short fiber content of 20-90% (w / w), preferably 50-80% (w / w).

[0116] The long fibers refer to fibers having a fiber length of 2.6 to 4.4 mm, and the short fibers refer to fibers having a fiber length of 0.7 to 2.2 mm.

[0117] Furthermore, 0% to 20%, preferably 0% to 5%, of fillers (the value 0% is preferably excluded), such as GCC (ground calcium carbonate), known for example under the trade name Hydrocarb 60 or Hydrolex 60, PCC (precipitated calcium carbonate), known for example under the trade name Precarb 105, natural kaolin and / or talc, as well as the usual auxiliary agents, such as retention and / or sizing agents, may be present.

[0118] The advantages of such base paper are, on the one hand, its high flexibility and low stiffness, on the other hand, its good processability in existing packaging systems relative to flexible materials such as plastic films; maintaining high machine usability; and achieving the required puncture resistance, burst strength and tear propagation.

[0119] Common packaging systems include vertical and horizontal form-fill-seal machines for the production of free-standing pouches, flow packs, pillow packs, etc.; machines that bring together two webs of the same or different material and join them by heat, cold or ultrasonic sealing, such as even tray sealers, chamber belt machines (also using vacuum), pouch fill and seal machines, thermoform packaging machines, linear fill machines that apply lids with heat sealing to seal, wrapping machines with a final heat sealing step, blister packaging machines, and X-fold packaging machines.

[0120] The barrier paper according to the invention is further preferably characterised in that a precoat comprising at least one inorganic pigment and a polymeric binder is present between the base paper and the coating colour layer S1.

[0121] The inorganic pigments are preferably platelet-like and include in particular talc, precipitated calcium carbonate or silicates, preferably phyllosilicates, most preferably kaolin.

[0122] As suitable polymer binders, mention may be made especially of acrylate-based or styrene / butadiene-based binders.In principle, all polymers that can be used as binders for pigment coating in the paper industry are suitable.Starch-based binders (solutions of modified starch, dispersions of crosslinked starch, so-called biolatexes) and polymer-starch hybrid latexes are also possible.

[0123] The polymeric binder preferably comprises a polyacrylate-based polymeric binder.

[0124] Generally, the precoat can be a hydrophobic precoat.

[0125] In another embodiment, the precoat is generally hydrophilic.

[0126] The precoat preferably contains 1-70% (w / w), preferably 5-50% (w / w) of polymer binder. The amount refers to the dry precoat in the final product.

[0127] The precoat also preferably contains 50-95% (w / w), preferably 80-90% (w / w), of inorganic pigment. The amount refers to the dry precoat in the final product.

[0128] Additionally, the precoat may contain additives such as thickeners, e.g., acrylate-based thickeners, surfactants, and / or rheology modifiers. The use of crosslinking agents is also contemplated. Preferably, the precoat contains a zirconium-based crosslinking agent, which itself is crosslinked with formaldehyde.

[0129] These additives are preferably present in an amount of 0-2% (w / w), preferably greater than 0-2% (w / w), with the value of 0% being preferably excluded. The amounts refer to the dry precoat in the final product.

[0130] The amount of precoat applied is preferably 1 to 10 g / m 2, and particularly preferably 2 to 6 g / m 2 The amount refers to the dry precoat in the final product.

[0131] When such a precoat (also called primer) is applied, it has the advantage that the surface of the paper is sealed and any further coating color layer 1 applied to it migrates very little into the paper, thus generating sufficient layer adhesion. Moreover, this precoat reduces the average roughness depth of the base paper, providing an advantageous "persistence" characterized by a full-area covering application and a well-defined surface energy, so that the coated coating color layer 1 can be optimally formed. Moreover, the precoat confers interlayer adhesion between the base paper and the coating color layer 1, which can be important for subsequent sealing applications.

[0132] The coating pigmented layer 1 applied to the precoat preferably comprises at least partially saponified polyvinyl alcohol and / or at least partially saponified polyvinyl alcohol copolymer. The formulations used in the treatment process preferably have a polymer content of 10 to 100, particularly preferably 50 to 99.8% (w / w).

[0133] The coating color layer 1 may further contain additives, such as thickeners, for example acrylate-based thickeners; surfactants, for example sulfosuccinates; extensional rheological aids, for example polyacrylamides, carboxymethylcellulose, polyvinyl alcohol; and / or crosslinkers, for example aldehydes and polyaldehydes, zirconates, polyepoxides, epichlorohydrin resins and / or hydrazides.

[0134] These additives are preferably contained in an amount of 0.1 to 1% (w / w) based on the total weight of the coating color layer 1.

[0135] In one embodiment the barrier paper according to the present invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has an average molecular weight of less than 100,000 g / mol.

[0136] In another embodiment the barrier paper according to the present invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has an average molecular weight of more than 30,000 g / mol, or more than 40,000 g / mol, or more than 50,000 g / mol, or more than 60,000 g / mol, or more than 70,000 g / mol.

[0137] In one embodiment the barrier paper according to the invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has a degree of saponification between 30% and 100%.

[0138] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has a degree of saponification of between 30% and less than 100%.

[0139] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has a degree of saponification of less than 95% or between 30% and 95%.

[0140] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has a degree of saponification between 95% and 100%.

[0141] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has a degree of saponification of between 95% and less than 100%.

[0142] In another embodiment the barrier paper according to the present invention is further preferably characterised in that the at least partially saponified polyvinyl alcohol and / or the at least partially saponified polyvinyl alcohol copolymer has an onset temperature of less than 200°C determined by DSC.

[0143] The barrier paper according to the invention is further preferably characterised in that the at least one polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification less than 95%, or between 30% and 95%, an average molecular weight greater than 0 g / mol and less than 100,000 g / mol and an onset temperature determined by DSC less than 200°C.

[0144] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least one polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification between 95% and 100%, an average molecular weight of more than 70,000 g / mol and an onset temperature determined by DSC of less than 200°C.

[0145] In another embodiment the barrier paper according to the invention is further preferably characterised in that the at least one polymer comprises a partially saponified polyvinyl alcohol copolymer, preferably a partially saponified polyethylene vinyl alcohol, having a degree of saponification between 95% and 100%, an average molecular weight of more than 60,000 g / mol and an onset temperature determined by DSC of less than 210°C.

[0146] Partially saponified polyvinyl alcohol copolymers, such as polyethylene vinyl alcohol, have generally been shown to be more flexible than polyvinyl alcohol.

[0147] In another embodiment the barrier paper according to the invention is preferably characterised in that the at least one polymer comprises a mixture of partially saponified polyvinyl alcohol with a degree of saponification between 1% and 95%, an average molecular weight between 0 and 100,000 g / mol and an onset temperature below 200° C. determined by DSC, partially saponified polyvinyl alcohol with a degree of saponification between 95% and 100%, an average molecular weight above 70,000 g / mol and an onset temperature below 200° C. determined by DSC and / or partially saponified polyvinyl alcohol copolymers, preferably partially saponified polyethylene vinyl alcohols, with a degree of saponification between 95% and 100%, an average molecular weight above 60,000 g / mol and an onset temperature below 210° C. determined by DSC.

[0148] The degree of saponification was determined according to DIN EN ISO 3681 as follows:

[0149] To polyvinyl alcohol (PVOH) (1 g), distilled water (70 mL) and neutralized ethanol (30 mL) are added and heated under reflux until complete dissolution. After cooling, the solution is neutralized with potassium hydroxide solution (0.1 M). In the case of the partially saponified PVOH form, more potassium hydroxide solution (50 mL, 0.1 M) is added and heated under reflux (60 min). In the case of the fully saponified PVOH form, a smaller amount of additional potassium hydroxide solution (25 mL, 0.1 M) was used, as well as a shorter reflux time (30 min), to prevent the absorption of carbon dioxide in the excess caustic solution. The excess caustic solution is then re-titrated with hydrochloric acid (0.1 M) using phenolphthalein as indicator. A blind test is performed in parallel.

[0150] The degree of saponification (%) can be calculated using Equation 1.

[0151]

number

[0152] The ester number is determined according to formula 2.

[0153]

number

[0154] The average molecular weight was as determined by size exclusion chromatography (GPC) under the following conditions: Eluent: DMSO / +0.1M LiCl; Precolumn: 10μm, Guard, ID 8.00mm x 50.00mm; Column: 10μm, 30Å, ID 8.00mm x 300.00mm; 10μm, 3000Å, ID 8.00mm x 300.00mm; 10μm, 3000Å, ID 8.00mm x 300.00mm; Pump: 1260 HPLC Pump; Flow Rate: 1.0mL / min; Injector: 1260 Autosampler; Injection Volume: 200μL; Sample Concentration: 5.0g / L; Temperature: 80℃; Detector: SECcurity 2 Refractive Index Detector (RI)-WEG eta 1001 HT Viscometer; Calculation: WinGPC UniChrom Version 8.33.

[0155] Samples were dissolved in solvent (5 mg / mL) at 80° C. for 3 h and injected via an autosampler.

[0156] To determine the calibration curve, several PMMA standards with different molecular weights were measured. The calibration curve was converted to a universal calibration curve by measuring the intrinsic viscosity.

[0157] The barrier paper according to the invention is further preferably characterised in that the polyvinyl alcohol has a viscosity at a dry content of 4% of less than 30 mPas or less than 20 mPas, particularly preferably less than 15 mPas.

[0158] Viscosity is determined at 23° C. using a Brookfield viscometer at 100 rpm.

[0159] Viscosities within this range have the advantage that higher solids contents can be used in the application, therefore lower energy must be used for drying, and furthermore faster processing speeds can be achieved. In addition to the economic advantages, this is also reflected in the use of a wider drying window on the coating system.

[0160] As already mentioned above, the quality of the barrier paper according to the invention, in particular with regard to its buckling resistance, can be determined by dynamic mechanical thermal analysis (DMTA).

[0161] Dynamic mechanical thermal analysis (DMTA) can also be used to determine the glass transition temperature (Tg), which is the temperature at which the polymer chains change from a solid, rigid state to a mobile state, but before they slide over one another (which corresponds to the melting point (Tm)). In order to maintain barrier properties after being creased or flexed, it is advantageous for a viscoelastic state to exist in the packaging material, and therefore a Tg below the operating and use temperature is ideal. The Tg is determined by the temperature at which maximum tanning is reached with DSC. Preferred polymers have a glass transition temperature Tg corresponding to a maximum tan.

[0162] The barrier paper according to the invention preferably has a breaking force in the running direction of the paper of more than 80N / 15mm, preferably more than 90N / 15mm, and transversely to the running direction of more than 40N / 15mm, preferably more than 50N / 15mm.

[0163] The barrier paper according to the invention also preferably has a dynamic coefficient of friction (CoF) of less than 0.7, preferably less than 0.6, particularly preferably less than 0.5, which refers to the friction of a coated surface on a coated surface (coating vs. coating).

[0164] The barrier paper according to the invention further preferably has a basis weight of the individual layers of 4 to 20 g / m2, based on the dry end product (air dried). 2 , preferably 4 to 15 g / m 2 It is characterized in that:

[0165] The barrier paper according to the invention is further preferably characterised in that coating B2 can be wetted with conventional water-based cold seal adhesives.To this end, the surface energy of coating B2 is more than 35 mN / m, more than 40 mN / m, preferably more than 50 mN / m, particularly preferably more than 55 mN / m.

[0166] Such wettability of coating B2 has the advantage that no coating-free areas form during the application and drying process of the cold seal adhesive, and also ensures sufficient adhesion when applied.

[0167] The barrier paper according to the invention is further preferably such that the barrier paper has an oxygen transmission rate (OTR) 10 cm of less than 10, preferably less than 5. 3 / m 2 / d (23°C, 0% relative humidity).

[0168] The barrier paper according to the invention is further preferably such that the barrier paper has an oxygen transmission rate (OTR) 10 cm of less than 10, preferably less than 5. 3 / m 2 / d (23°C, 50% relative humidity).

[0169] The barrier paper according to the invention is further preferably such that the barrier paper has an oxygen transmission rate (OTR) 10 cm of less than 20, preferably less than 15. 3 / m 2 / d (23°C, 70% relative humidity).

[0170] The barrier paper according to the invention is further preferably such that the barrier paper has an oxygen transmission rate (OTR) 10 cm of less than 50, preferably less than 40. 3 / m 2 / d (23°C, 80% relative humidity).

[0171] Preferably, the barrier paper according to the invention also does not lose this oxygen barrier through the mechanical stress of a 180° bend with a roller applying a load of 330 g / cm to the resulting bend, the coating being either on the inside (inner bend) or on the outside (outer bend).

[0172] Oxygen transmission rate (OTR) is determined according to ISO 15105-2.

[0173] The barrier paper according to the invention is further preferably characterised in that the barrier paper has a grease barrier according to condition I according to DIN 53116.

[0174] Preferably, the barrier paper according to the invention also does not lose this grease barrier due to the mechanical stress of a 180° bend with a roller applying a load of 330 g / cm to the resulting bend, the coating being either on the inside (inner bend) or on the outside (outer bend).

[0175] The barrier paper according to the invention is further preferably of a thickness of 10 g / m 2 / d of mineral oil barrier (hexane).

[0176] Preferably, the barrier paper according to the invention also does not lose this mineral oil barrier (hexane) by the mechanical stress of a 180° bend with a roller applying a load of 330 g / cm to the resulting bend, the coating can be on the inside (inner bend) or on the outside (outer bend).

[0177] Mineral oil barrier as determined by filling a beaker (solvent resistant) with hexane, sealing tightly with coated paper and monitoring weight loss over time.

[0178] The barrier paper according to the invention is further preferably such that the barrier paper has a water vapour permeability g / m of less than 10, preferably less than 5. 2 / d (23°C, 50% relative humidity).

[0179] The barrier paper according to the invention is further preferably such that the barrier paper has a water vapour permeability g / m of less than 10, preferably less than 5. 2 / d (23°C, 85% relative humidity).

[0180] The barrier paper according to the invention is further preferably such that the barrier paper has a water vapour permeability g / m of less than 10, preferably less than 5. 2 / d (38°C, 50% relative humidity).

[0181] The barrier paper according to the invention is further preferably such that the barrier paper has a water vapour permeability g / m of less than 20, preferably less than 10. 2 / d (38°C, 70% relative humidity).

[0182] The barrier paper according to the invention is further preferably such that the barrier paper has a water vapour permeability g / m of less than 20, preferably less than 10. 2 / d (38°C, 90% relative humidity).

[0183] The barrier paper according to the invention is further preferably characterised in that the barrier paper has a water vapour barrier which is maintained even when the coating comes into contact with grease, although not all water vapour barriers are.

[0184] The barrier paper according to the present invention is further preferably characterised by being resistant to buckling without bending as well as in inward and outward bending.

[0185] The coated paper according to the invention is characterized by recyclability via the waste paper cycle, preferably conditionally recyclable, preferably by evaluation according to PTS PTS-RH 021.

[0186] The coated paper according to the invention is characterized by recyclability via the waste paper cycle, preferably according to the evaluation according to UNI 11743, level C, preferably level B, particularly preferably level A, very particularly preferably level A+.

[0187] The coated paper according to the invention is characterized by its biodegradability in a marine environment according to ASTM D7081.

[0188] The barrier paper according to the invention is perceptually harmless and achieves a value of at least 2 or less (according to standard DIN 1230-1:2010-02).

[0189] The barrier paper according to the invention can be heat sealed, preferably producing a sealed seam strength (cold tack) of more than 3.5 N / 15mm, particularly preferably more than 5.0 N / 15mm at the optimum sealing temperature, the sealed seam strength of the barrier paper being determined as follows:

[0190] The barrier papers were sealed perpendicular to the running direction of the paper at 3.3 bar for 0.3 s in the temperature range 100 °C-230 °C and the strength of the sealed seam (cold tack) was determined according to DIN 55529 (2012).

[0191] "Heat sealing" is preferably understood to mean joining two layers of barrier paper using localized heat and / or pressure. In further embodiments, the coated side of the paper may also be joined by heat sealing to the opposite side of a paper that is not itself heat sealable, to the opposite side of a paper that is heat sealable, or to another paper.

[0192] Due to its compatibility with common cold seal media, the barrier paper according to the invention is also cold sealable. Cold seal is generally understood to mean that a cold seal adhesive is applied to a section of flat packaging material that is sealed using a pressure process. The cold seal adhesive has the property that it only exerts its adhesive effect under and after increased pressure between the sealing jaws of a packaging machine and does not otherwise stick, or only to a limited extent.

[0193] Ultrasonic sealing means concentrating the energy of ultrasound on the area to be welded, concentrating the heat that is generated by friction, especially in heat sealing. Typical sealing times are between 100-200 milliseconds. In contrast to heat sealing, for example, using sealing jaws, the heat required with ultrasonic technology is generated only within the materials to be welded. The tool remains cool, helping dissipate the heat.

[0194] Heat sealed barrier paper, cold sealed barrier paper and ultrasonically sealed barrier paper are characterized by high moisture resistance of the sealed seams.

[0195] The barrier paper according to the present invention is also tear resistant.

[0196] The barrier paper according to the invention is further characterized in that the taste of the food packaged therein is not affected.

[0197] Barrier papers according to the invention can be obtained economically using known manufacturing processes.

[0198] However, it is preferred to obtain the barrier paper according to the invention by a process in which an aqueous suspension comprising the starting materials for the coating colour layer S1 is applied to the base paper, the aqueous application suspension having a solids content of 5 to 50% by weight, preferably 10 to 30% by weight, and is applied by a curtain coating process, preferably a double curtain coating process, at an operating speed of the coating system of at least 200 m / min.

[0199] This process is particularly advantageous from an economic standpoint and due to the uniform application across the paper web.

[0200] If the solids content falls below about 10% by weight, the economic efficiency decreases, since large amounts of water have to be removed in a short time by gentle drying, which has a negative effect on the coating speed. On the other hand, if the value exceeds 50% (w / w), the technical efforts to ensure the stability of the coated color curtain during the coating process and drying of the applied film only increase, since in this case the machines still have to work very quickly.

[0201] In the curtain coating process, a free-falling curtain of coating dispersion is formed. The coating dispersion in the form of a thin film (curtain) is "poured" by free fall onto a substrate to apply the coating dispersion to the substrate. DE10196052T1 discloses the use of the curtain coating process in the manufacture of information recording materials, where a curtain of several coating dispersion films is applied to a substrate to realize a multi-layer recording layer.

[0202] In a preferred embodiment of the method according to the invention, the aqueous deaerated application suspension has a viscosity of about 100 to about 800 mPas (Brookfield, 100 rpm, 20° C.). If the value falls below about 100 mPas or exceeds about 800 mPas, this results in poor handling of the coating material in the coating unit. Particularly preferably, the viscosity of the aqueous deaerated application suspension is about 200 to 500 mPas.

[0203] In a preferred embodiment, the surface tension of the aqueous application suspension may be adjusted to about 25 to about 70 mN / m, preferably about 35 to about 60 mN / m (measured according to the standard for bubble pressure tensiometers (ASTM D3825-90) as described below) to optimize the process. By determining the dynamic surface tension of the coating color and adjusting that surface tension by selecting an appropriate surfactant and determining the required amount of surfactant, better control over the coating process may be achieved.

[0204] Compared to dispersions, especially those with small particle size and therefore high particle surface area, polyvinyl alcohol solutions require significantly less surfactant to generate the same surface tension.

[0205] Dynamic surface tension is measured using a bubble pressure tensiometer. The maximum internal pressure of a bubble formed through a capillary in a liquid is measured. According to the Young-Laplace equation, the internal pressure p (Laplace pressure) of a spherical bubble depends on the curvature r and the surface tension σ:

[0206]

number

[0207] When a bubble is generated at the tip of the capillary in the liquid, the curvature first increases and then decreases again, resulting in the occurrence of a pressure maximum. The maximum curvature, and therefore the maximum pressure, occurs when the radius of curvature corresponds to the radius of the capillary.

[0208] Pressure characteristics of bladder pressure measurement, position of maximum pressure:

[0209] The radius of the capillary is determined using a reference measurement made with a liquid of known surface tension, usually water. Once the radius is known, the surface tension can be calculated from the maximum pressure pmax. Since the capillary is immersed in the liquid, the hydrostatic pressure p0, which is obtained from the immersion depth and the density of the liquid, must be subtracted from the measured pressure (this is done automatically in modern instruments). This gives the following equation for the bubble pressure process:

[0210]

number

[0211] The measurements correspond to the surface tension at a particular surface time, i.e., the time from the start of bubble formation to the occurrence of maximum pressure. By varying the rate at which bubbles are generated, the dependence of surface tension on surface time can be obtained, resulting in a curve in which surface tension is plotted against time.

[0212] This dependence plays an important role in the use of surfactants, since in many processes the interfacial tension never even reaches the equilibrium value due to the sometimes low diffusion and adsorption rates of the surfactants.

[0213] The individual coatings can be formed on-line on a papermaking machine having a coating unit, or can be formed off-line on the coating machine as separate coating processes.

[0214] In other embodiments, the individual layers may also be applied to the base paper using the following process:

[0215] The coating colour layer S1 may be applied to the base paper and / or to an existing pre-coat using a printing process.

[0216] The coating color layer S1 may be applied to the base paper and / or to an existing precoat using extrusion.

[0217] This technique has the advantage that much more material can be applied, but this is only interesting if the entire product does not need to be recyclable as paper. The disadvantages are the slower application speed, higher energy consumption and higher minimum application weight.

[0218] The coating colour layer S1 may be applied by laminating or backing the paper, for example in the form of a plastic film on the base paper and / or an existing precoat.

[0219] The coating colour layer S1 and the precoat may also be applied one after the other over several application steps.

[0220] The present invention further relates to a barrier paper obtainable by the above-mentioned process.

[0221] Due to its relatively high polarity, the coating pigmented layer S1 is also suitable for applying an additional barrier in the form of an aqueous polymer solution or dispersion by melt extrusion or film lamination.

[0222] The coating colour layer S1 may be smoothed to achieve a Beck smoothness of at least 200 Beck seconds, in particular 500 Beck seconds.

[0223] Further layers are applied to the metallization layer by vacuum deposition.

[0224] If necessary, the coating color layer S1 can be improved in terms of all barriers by applying a barrier layer B1, in particular an ultra-thin metal layer, metal oxide layer or other inorganic compound, by deposition or especially vacuum deposition. Such thin barrier layers are only effective if they do not contain any particles (e.g. inorganic pigments) and are adhered to very smooth flexible substrates on which they can form a closing layer. The relatively high surface energy of the coating color layer S1, in particular the surface energy of the overall polymer, favors interlayer adhesion of polar materials such as metal oxides and other inorganic oxides, as well as polarizable conductive materials such as metals. The barrier paper thus obtained can, on the other hand, be made resealable by applying a heat seal layer or a cold seal adhesive.

[0225] A further coating B2 is applied to the vacuum-deposited barrier layer B1 using gravure printing (or even curtain coating or other printing processes). Non-contact application has the advantage that the surface of the material to be coated cannot be destroyed or adversely affected.

[0226] The present invention also relates to the use of a barrier paper as described above or obtainable by the process as described above as packaging material.

[0227] Finally, the present invention also relates to the use of a barrier paper as described above, or obtainable by the process as described above, as packaging material for food products, in particular fatty, moisture-sensitive and oxidation-sensitive food products.

[0228] The present invention further preferably relates to the use of the barrier paper as defined above, or of a barrier paper obtainable by the process as defined above, as packaging material for e.g. cereal bars, chocolate, meat, sausages, cheese, chocolate containing products, butter and margarines, snacks, chips such as potato or lentil chips, products baked with vegetable oils such as chips, savory snacks, biscuits, crackers, protein bars, sports and fitness bars, dietary supplements, soup bases, cosmetic products such as powders and cosmetics, coffee and tea, pet food, tobacco products (e.g. as inner liner), yoghurt (as lid).

[0229] In a further preferred embodiment of the present invention, the barrier paper according to the invention is applied to cardboard or carton board, in particular by backing, laminating or gluing.

[0230] Finally, the present invention also relates to the use of a composite in which a barrier paper according to the invention is applied to cardboard or board, in particular by backing, lamination or gluing, as packaging material for food products, in particular fatty and oxidation-sensitive food products.

[0231] This allows for the easy and economical production of packaging materials that offer the advantages of both material components, e.g., the increased strength and stiffness of corrugated or cardboard compared to coated paper, as well as the advantages of the barrier paper mentioned above. Application can be carried out, for example, using starch or aqueous dispersion adhesives.

[0232] Preferably therefore the barrier paper may be a component of a corrugated or cardboard based packaging material.

[0233] These packaging materials according to the invention allow especially heavier food products to be safely packaged and presented to customers in an attractive manner in the store in the form of freestanding packages.

[0234] These packaging materials preferably have a mass fraction of more than 95% (w / w) of homogeneous material type paper, corrugated board or cardboard. Now, a further advantage of the present invention is that these packaging materials according to the invention are not composite packaging according to § 3(5) of the Packaging Act, so that this embodiment of the invention contributes significantly to reducing the impact of packaging waste on the environment.

[0235] The present invention also relates to packaging comprising the barrier paper described above or as a composite with the corrugated or cardboard described above.

[0236] The features of the use according to the invention apply equally to the packaging according to the invention.

[0237] The packaging may be a cold seal packaging. Cold seal packaging is preferably suitable for packaging food products such as chocolate, chocolate-containing products, bars, e.g. muesli bars, and / or other confectionery. This is due on the one hand to the heat sensitivity of chocolate and on the other hand to the machine speeds which may be higher. Since the heating of the heat-sealing medium takes a relatively long time, packaging machines based on cold seal can operate more quickly.

[0238] The packaging may also be a heat-sealed packaging, which is preferably suitable for use as a secondary packaging or for containers with dispense and fill scales.

[0239] The packaging may also be a cold seal packaging.

[0240] The packaging may further be primary or secondary packaging, especially heat or cold sealed tubular packaging, flow wraps, stand-alone pouches, wrappers, 3 and 4 side sealed pouches, lids.

[0241] The barrier paper can also be used folded over so that the inside faces the outside and the outside faces the inside. This makes it extremely safe for use in moist environments. In this case an additional partial or full surface sealing lacquer must be applied or the packaging must be ultrasonically sealed. In this case the B2 coating is coated or printed.

[0242] Coating B2 may be opaque to prevent light from penetrating through barrier layer B1. Alternatively, coating B2 may also be printed with an opaque layer.

[0243] Preferably, the barrier paper according to the invention comprises at least one base paper having two faces (surfaces) with different roughness (rougher face and g). Preferably, the rougher face (r) of the base paper is used for coating with the precoat, coating colour layer S1, barrier layer B1 and barrier layer B2 (inner face). The less rough face (r) is used for printing, preferably by gravure printing (outer face).

[0244] In a particular embodiment, the smoother side (g) can also be used for coating with precoat, coating color layer S1, barrier layer B1 and barrier layer B2 (inner surface) and the rougher side (r) can be used for printing (outer surface). This embodiment is less printable but due to its lower roughness surface, it can result in an improvement of the barrier properties of coating color layer S1 or a saving of material of coating color layer S1 while maintaining the same barrier properties (e.g. the same properties at a lower layer thickness).

[0245] In the following the invention will be explained in more detail with reference to non-limiting examples and figures. [Brief description of the drawings]

[0246] [Figure 1]Figure 2 shows two basic structures a) and b) of a barrier paper according to the invention with the following reference symbols: 1: base paper, g: smoother surface of the base paper, r: rougher surface of the base paper, 2: coating colour layer S1, 3: barrier layer B1, 4: coating B2, 5: optional pre-coat for better coating colour persistence to prevent the coating colour layer S1 from penetrating into the base paper, 6: optional starch pre-coat for better printability, 7: barrier paper according to the invention, A: sealing surface A of the barrier paper, B: sealing surface B of the barrier paper, A / A seal, A / B seal, 8: further coating colour layer S1 of the same or different composition / layer thickness as 2, not shown: printing on the barrier paper using standard printing processes, in particular using flexo, gravure or digital printing processes. [Diagram 2] 2 SEM surface images of comparative example V3 (inward bending) at different resolutions. Top coating (B1) as top view. As can be seen, the surface is broken due to buckling strain. [Diagram 3] 2 SEM surface images of Example B1 (inward bending) at different resolutions. Top coating (coating B2) as a top view. As can be seen, the coating is distorted by buckling stress but not broken. [Figure 4] Two SEM surface images of comparative example V5 (inward bending). Top coating (B2) as a top view. Here the coating color layer S1 is not visible. As can be seen, the surface is broken due to buckling strain. [Diagram 5] Two images of comparative example V1 after palm kernel fat test (inner bend on the left, outer bend on the right). Top coating (coating color layer S1) as top view. In this case the layer thickness was split in half. It can be observed that splitting in half does not lead to any problems in flat grease barrier (right and left of the bend) but leads to problems in buckling resistance (grease seepage at the bend and edge area of ​​the bend). [Figure 6]Two images of comparative example V2 after palm kernel fat test (left: inner bend, right: outer bend). Top coating (coating color layer S1) as top view. In this case, the preferred layer thickness was selected. It can be observed that there is a flat fat barrier (right and left of the bend) or no buckling resistance problems (no fat penetration at the bend and in the edge area of ​​the bend). [Figure 7] 1A-1D show various packaging configurations with A:A seals according to the present invention. [Figure 8] FIG. 1 shows an envelope-style package according to the present invention having an A:B seal on the front. [Figure 9] Figure 2 is a schematic diagram of a typical DMTA measurement graph of a barrier paper according to the invention, where the measured loss factor tan delta is plotted as a function of temperature. As the temperature is increased, there is an initial maximum at temperature Tg, followed by a first inflection point at temperature Tw. [Figure 10] FIG. 2 shows DMTA measurements of Examples 9 and 10 according to the invention compared to Comparative Example V2 according to Table 2. EXAMPLES

[0247] The invention will now be described in more detail in some examples, which serve only to illustrate the invention and not to limit it.

[0248] The following coatings are applied to the 60g / m2 100% virgin fibre pulp. 2 or 70 g / m 2 The test was applied to a base paper having a basis weight of 100 g / m2 and a content of 40% long fibres and 60% short fibres.

[0249] Precoat: In all examples, the precoat contains 75.9% pigment (phyllosilicate), 22.8% latex (styrene-acrylate latex) and 1.3% rheology modifier (0.2% acrylate-based thickener, 1.1% zirconium-based crosslinker). The precoat was applied to the base paper using a doctor blade.

[0250] Coating color layer S1: Polyvinyl alcohol was used as the polymer in Examples 1 to 5. Partially saponified polyethylene vinyl alcohol was used as the polymer in Examples 6 to 8.

[0251] The coating color layer S1 of Examples 1 to 5 comprises a pure polymer coating. Example 1' contains 99.8% polyvinyl alcohol as the polymer (Example 1; saponification degree: 87%; M w :50900), and a polymer coating containing 0.2% rheology modifier (Na docusate).

[0252] The coating color layer S1 of Examples 9 and 10 and Comparative Examples 1, 2, 3, and 5 corresponds to the coating color layer S1 of Example 1. Use of the coating color layer S1 from Example 1' gave comparable results.

[0253] Barrier layer B1: In Examples 9 and 10 and Comparative Examples 1, 2, 3 and 5, a barrier layer B1 of about 40 nm to 80 nm thickness was applied directly or as a precoat to the coating color layer S1 by vacuum deposition of aluminum.

[0254] Coating B2: An embodiment using gravure printing and an embodiment using curtain coating.

[0255] The following properties were tested:

[0256] Grammage or Application Weight: g / m 2 The applied weight of the coating at 150° C. as determined by differential weight measurements of the coated and uncoated paper.

[0257] viscosity: The viscosity was determined using a Brookfield viscometer at 23° C. and a speed of 100 rpm at a dry content of 4%.

[0258] WVTR: Water vapor transmission rate determined according to ASTM D1653. For the bent specimens, a 180° bend is generated with a roller exerting a load of 330 g / cm on the resulting bend, and the coating can be on the inside (inner bend) or outside (outer bend).

[0259] OTR: Oxygen transmission rate determined according to DIN 15105-2. For the bent specimens, a 180° bend is generated with a roller exerting a load of 330 g / cm on the resulting bend, and the coating can be on the inside (inner bend) or outside (outer bend).

[0260] HVTR: Hexane vapor transmission rate, where n-hexane is filled into a beaker (solvent resistant), tightly sealed with a test specimen, and weight loss is followed over time. For bent specimens, a 180° bend is generated by a roller that applies a load of 330 g / cm to the resulting bend, and the coating can be on the inside (inner bend) or outside (outer bend).

[0261] Palm Kernel Fat Test: Similar to DIN 53116. For bent specimens, a 180° bend is produced by a roller that applies a load of 330 g / cm to the resulting bend, and the coating can be on the inside (inner bend) or outside (outer bend).

[0262] Display paper: Evaluation of the display papers referred to in DIN 53116. For this, the fat penetration points with a diameter (d) of less than 1 mm (first value in the table) and more than 1 mm (second value in the table) are counted.

[0263] Test strips: Evaluation of the reverse side of the test paper as referred to in DIN 53116. This is not part of the standard but was done for better differentiation.

[0264] Sealed seam strength: The samples are sealed perpendicular to the paper running direction at 3.3 bar for 0.3 seconds in the temperature range 100°C to 220°C and the strength of the sealed seam is determined according to DIN 55529 (2012). The optimum sealing temperature and, for comparison, the sealing force at 150°C (optimum sealing temperature of Example 1) are shown.

[0265] Friction coefficient: The static and kinetic coefficients of friction were determined according to ISO8295. Back-to-back coefficient of friction: Two test specimens were mated with their functionally coated faces against each other and the coefficient of friction was determined (inside / inside). Coefficient of friction between backside and barrier side: The functional coating side of the barrier paper (barrier side) was measured against the metal surface of the device (inside / barrier side).

[0266] DSC Melt Temperature / Onset: DSC curves were measured on a Mettler DSC 20S in a pressure-welded aluminum crucible and a perforated lid. The heating rate was 10 K / min in the range of 30°C to 280°C. The melting temperature was determined by the peak-minimum of the melting process. Necessary?

[0267] Surface tension (surface energy): Contact angle measuring device OCA20 (DataPhysics) with software SCA20. Measurement principle: OWRK method (Owens, Wendt, Rabel, Kaelble). The measuring solutions used and the origin of the entered material constants: water and diiodomethane (according to Buscher) and 1,5-pentanediol (according to Gebhardt).

[0268] Friction Sensitivity Oser Test 1) Measure the barrier properties of the upper barrier paper. 2) Place the barrier paper stack in the Oser test device (barrier facing down), press down with 500g and turn the device on for 60 seconds. The weight is then lifted again. 3) Measure the barrier properties of the upper barrier paper.

[0269] The resulting barrier paper was tested and the results are shown in the table below.

[0270] Table 1 shows the results for intermediate products which only have the coating colour layer S1 but do not yet have the barrier layer B1 and the coating B2 (Examples 1 to 8).

[0271] Table 2 shows the results especially for the barrier papers according to the invention having the coating colour layer S1, the barrier layer B1 and the coating B2 (Examples 9 and 10) and for the comparative examples V1 to V5.

[0272] The partially saponified polyvinyl alcohol used has very low hexane and oxygen permeability, probably due to its relatively high hydrophilicity.

[0273] Polyvinyl alcohols with a higher degree of saponification are characterized by a higher viscosity at the same dry content in coating pigments. This only makes sense from a chemical point of view, since higher polarity means that each molecule interacts more strongly with the surrounding solvent (water).

[0274] This must be considered somewhat disadvantageous, because at low dry content, a large amount of water must be dried in the coating process. This is not only energy-intensive, but can be difficult to achieve in terms of application technology, depending on the desired application weight. Moreover, the diffusion of water molecules, and thus the drying process itself, slows down. Moreover, the accumulation of gaseous water in the coating is likely to occur, leading to the formation of macroscopic coating defects.

[0275] The water vapor permeability of the polyethylene vinyl alcohol tested is lower than that of polyvinyl alcohol, likely due to the ethylene content and associated lower hydrophilicity.

[0276] Generally, fully saponified polyvinyl alcohol (PVOH) should be more brittle than partially saponified PVOH due to the large number of hydrogen bonds they can form.

[0277] In particular, in order to maintain essential or all of the barrier properties of the barrier paper even at the fold bend or fold area after buckling, the barrier paper according to all embodiments of the present invention has the following features:

[0278] a) For all barrier papers according to these examples, the value of loss factor tan delta as a function of temperature measured by Dynamic Mechanical Thermal Analysis (DMTA) of the barrier paper passes through a maximum value at a temperature Tg and a first inflection point at a temperature Tw with increasing temperature.

[0279] b) For all barrier papers according to these examples, the temperature Tg is also lower than the temperature Tw.

[0280] c) The amount of difference between tan delta at temperature Tg and tan delta at temperature Tw is greater than 0.013 for all barrier papers according to these examples.

[0281] Without being bound by this theory, the inventors consider the following:

[0282] It has been shown by dynamic mechanical thermal analysis (DMTA) that barrier papers according to the invention can maintain their barrier after buckling if the barrier paper has a significant viscoelastic component. The so-called "rubber elastic region" state can be interpreted by quantifying the change in tan delta value (tan δ at the glass transition temperature (Tg) relative to the first inflection point (Tw) of the tan delta curve with increasing temperature). Barrier materials that maintain their barrier properties after buckling, which may surprisingly also include a metal coating layer, have a tan delta change of more than 0.013.

[0283] Dynamic Mechanical Thermal Analysis (DMTA) also provides the glass transition temperature (Tg), which is the temperature at which the macromolecular polymer chains transition from a solid, rigid state to a mobile state, but before they slide over one another (this is the melting point (Tm)). In order to maintain the barrier after being creased or bent, it is advantageous for the barrier paper to have an elastic state, and therefore a Tg below the operating and use temperature is ideal. In DSC, Tg is as determined by the temperature at which tan delta reaches a maximum. One example has a glass transition temperature Tg=8.4° C., corresponding to a tan delta maximum of 0.099 and a tan delta change of 0.0185.

[0284] [Table 1]

[0285] [Table 2] TIFF2025511990000011.tif116170TIFF2025511990000012.tif112169TIFF2025511990000013.tif100170

Claims

1. at least The original paper and The base paper comprises at least one coating color layer S1 applied directly or indirectly, At least one barrier layer B1 applied directly or indirectly to the coating color layer S1, Coating B2 applied directly or indirectly to the barrier layer B1 and Barrier paper equipped with [a specific feature].

2. The aforementioned colored coating layer S1 has the following characteristics: Water vapor barrier, Oxygen barrier, Mineral oil barrier, Fragrance barrier, Lipid barrier, Buckling resistance of at least one property, Grease resistance, sealing properties Beck smoothness of at least 200 Beck seconds The barrier paper according to claim 1, characterized in having at least one of the following.

3. The barrier paper according to claim 1 or 2, characterized in that the coating color layer S1 contains or consists of at least one water-soluble polymer and / or at least one water-dispersible polymer.

4. The at least one water-soluble polymer and / or the at least one water-dispersible polymer, Polyvinyl alcohol, especially partially saponified or fully saponified polyvinyl alcohol; Polyvinyl alcohol copolymers, particularly partially saponified or fully saponified polyvinyl alcohol copolymers copolymerized with ethylene, polyvinylamine, or acrylic acid derivatives; Modified fully or partially saponified polyvinyl alcohol or copolymers, particularly those modified with acyl, alkyl, acrylamide, silanol, diacetone, acetoacetyl, or itaconic acid; A polymer having an onset temperature of less than 210°C as determined by DSC, wherein the onset temperature is determined by DSC in accordance with DIN EN ISO 11357-1:2010-03 as the intersection of the extrapolated baseline and the inflection point tangent at the onset of the melt or crystallization peak; Acrylic-based polymer; Polyester-based polymer; Nitrocellulose-based polymer; Polyvinyl acetate-based polymer The barrier paper according to claim 3, characterized in that it is selected from the group consisting of the following.

5. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises at least partially saponified polyvinyl alcohol and / or at least partially saponified polyvinyl alcohol copolymer, each having an onset temperature of less than 210°C as determined by DSC.

6. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification of 30% to 95%, an average molecular weight greater than 0 g / mol and less than 100,000 g / mol, and a starting temperature of less than 200°C determined by DSC.

7. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises a partially saponified polyvinyl alcohol having a degree of saponification of more than 95% to 100%, an average molecular weight of more than 70,000 g / mol, and an onset temperature of less than 200°C determined by DSC.

8. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises a partially saponified polyvinyl alcohol copolymer having a degree of saponification of 95% to 100%, an average molecular weight greater than 60,000 g / mol, and an onset temperature of less than 210°C determined by DSC, preferably a partially saponified polyethylene vinyl alcohol.

9. The barrier paper according to claim 3, characterized in that the partially saponified polyvinyl alcohol and / or the partially saponified polyvinyl alcohol copolymer has a viscosity of less than 30 mPas, particularly preferably less than 20 mPas, and most particularly preferably less than 15 mPas, at a dry content of 4%.

10. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and / or the at least one water-dispersible polymer comprises a mixture of the plurality of polymers defined in claim 3.

11. The barrier paper according to claim 1, characterized in that the coating colored layer S1 has a surface tension in the range of 25 to 80 mN / m, particularly 25 to 75 mN / m.

12. The barrier layer B1 is made of metals, particularly Al, Cu, Sn, Zn, Ag, Au, Ti, In, Si, metal alloys, metal oxides, particularly Al ２ O ３ SiO ２ The barrier paper according to claim 1, characterized by containing or consisting of mixed oxides or combinations thereof.

13. The barrier paper according to claim 1, characterized in that the barrier layer B1 is applied by vacuum deposition.

14. The barrier layer B1 has the following characteristics: a) Optical density of 1.5 or more and 6.0 or less, b) The barrier paper according to claim 1, characterized in that it has at least one of a layer thickness of 5 nm or more, preferably 10 nm or more, particularly preferably 15 nm or more, and especially 5 nm to 150 nm.

15. The coating B2 is made of at least one polymer, particularly a) Polyethylene acrylic acid copolymer, b) Polyolefins, c) Polyvinyl alcohol, d) Cellulose nitrate, e) Bio-based polymers, f) Non-biobased polymers, g) Styrene-butadiene latex, h) Acrylates The barrier paper according to claim 1, characterized by comprising or consisting of a polymer selected from the group comprising the above.

16. The coating B2 has the following characteristics: a) Protection of barrier layer B1 against external influences, particularly mechanical or chemical influences. b) Sealing properties, especially high temperature, ultrasonic, and cold sealing properties c) Grease resistance; d) water resistance; e) Moisture resistance, f) printability; g) Additional barrier properties The barrier paper according to claim 1, characterized in having at least one of the following.

17. The barrier paper described above has the following features: a) WVTR of 5 g / m² / d or less at 23°C and 50% relative humidity, b) WVTR (internal flexure) of 5 g / m² / d or less at 23°C and 50% relative humidity, c) WVTR (Wide Ventriloquism) of 5 g / m² / d or less at 23°C and 50% relative humidity. d) WVTR of 15 g / m² / d or less at 38°C and 90% relative humidity, e) WVTR (internal flexure) of 15 g / m² / d or less at 38°C and 90% relative humidity. f) WVTR (Wide Ventriloquism) of 15 g / m² / d or less at 38°C and 90% relative humidity. g) 10 g / m² at 23°C and 50% relative humidity ２ / d or less OTR, h) OTR (internal bending) of 10 g / m² / d or less at 23°C and 50% relative humidity. i) OTR (outer bending) of 10 g / m² / d or less at 23°C and 50% relative humidity, j) Buckling resistance of at least one barrier property, particularly in the regions of internal and / or external bending, k) A residual moisture content of at least 2.5% (w / w), and particularly at least 3.0% (w / w), based on the total weight of the barrier paper. The barrier paper according to claim 1, characterized in having at least one of the following.

18. The barrier paper according to claim 1, characterized in that the coating color layer S1, the barrier coating B1, and the coating B2 are removable in the recycled paper cycle.

19. After reprocessing according to the INGEDE method 11, the following scores are obtained based on the evaluation of print recyclability and deinkability score: a) Brightness Y of up to 35 points, b) Color coefficient a in the CIELAB system with a maximum of 20 points ＊ , c) Dirt stains A in two different size classes, A50 with a maximum of 15 points and A250 with a maximum of 10 points. d) The degree of dye removal (ink removal) of up to 10 points IE, and e) Darkening of the filtrate by up to 10 points ΔY, The barrier paper according to claim 18, characterized in that the total of all points reaches a value in the range of 0 to 100, preferably in the range of 51 to 70, more preferably in the range of 71 to 100, and / or preferably the individual point values ​​are not negative.

20. The barrier paper according to claim 1, wherein a precoat comprising at least one inorganic pigment and a polymer binder is present between the base paper and the coating color layer S1, the inorganic pigment is preferably in the form of small plates and preferably comprises talc, precipitated calcium carbonate, silicate, preferably phyllosilicate or kaolin, and / or the polymer binder comprises a polymer binder based on polyacrylate or styrene-butadiene.

21. The basis weight of the aforementioned colored coating layer S1 and coating B2 is 4 to 20 g / m², based on the final dried product (air-dried). ２ Preferably 4 to 15 g / m ２ The barrier paper according to claim 1, characterized in that it is within the range.

22. The barrier paper according to claim 1, characterized in that it does not contain halogenated organic compounds.

23. The base paper has a basis weight of 20 to 120 g / m ２ , preferably 40 to 100 g / m ２ The barrier paper according to claim 1, characterized in that it has a basis weight of

24. The barrier paper according to claim 1, characterized in that the base paper has a long fiber content of 10 to 80% and a short fiber content of 20 to 90% (w / w), wherein the long fibers are fibers having a fiber length of 2.6 to 4.4 mm and the short fibers are fibers having a fiber length of 0.7 to 2.2 mm.

25. The barrier paper according to claim 1, characterized in that the base paper contains up to 90% recycled fibers.

26. The barrier paper according to claim 1, characterized in that the value of the loss coefficient tan delta, measured as a function of temperature by dynamic mechanical thermal analysis (DMTA) of the barrier paper, passes through a maximum value at temperature Tg and a first inflection point at temperature Tw as the temperature increases.

27. The barrier paper according to claim 26, characterized in that the temperature Tg is lower than the temperature Tw.

28. The barrier paper according to claim 26 or claim 27, characterized in that the difference between the tan delta at temperature Tg and the tan delta at temperature Tw is greater than 0.013, preferably greater than 0.014, and particularly preferably greater than 0.

015.

29. A method for manufacturing barrier paper according to claim 1, A method characterized in that an aqueous suspension containing the starting material for the coating color layer is applied to the base paper, the aqueous coating suspension having a solid content of 5 to 50% by weight, preferably 10 to 30% by weight, and is applied by a curtain coating process, preferably a double curtain coating process, at an operating speed of at least 200 m / min of the coating plant.

30. Use of the barrier paper described in claim 1, or the barrier paper obtained by the method of claim 26, as a packaging material for food, consumer goods, tobacco products, or as a component of packaging materials, particularly corrugated or cardboard-based packaging materials, particularly as a packaging material for food, particularly sausages, cheese, coffee, muesli bars, chocolate, chocolate-containing products, or chips.

31. A package comprising the barrier paper described in claim 1, or a barrier paper obtainable by the method described in claim 29, which is preferably a cold-seal package, a heat-seal package, an ultrasonic-seal package, or more particularly a tubular bag package.

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