BIO-BASED COMPOSITES AS WATER VAPOR BARRIER ON PAPER

Abstract

The application relates to a coated paper comprising a base paper and at least one coating applied directly or indirectly onto the base paper, wherein the coating comprises a) at least one natural wax and/or at least one carboxylic acid component; and b) at least one natural resin; wherein the permeability of the coated paper for at least one gas is reduced compared to the base paper. Furthermore, the application relates to the coating used for producing the coated paper, the production method, and the packaging produced therefrom.

Claims

1. A coated paper comprising a base paper and at least one coating layer applied directly or indirectly onto the base paper, wherein the coating layer comprises a) at least one natural wax and/or at least one carboxylic acid component; and b) at least one natural resin selected from the group consisting of shellac, turpentine, balsam, gum lacquer, colophony, sandarac, mastic, coniferous resin, dammar, gum arabic, and elemi; wherein the permeability of the coated paper for at least one gas is reduced compared to the base paper.

2. A coated paper comprising a base paper and at least one coating layer applied directly or indirectly onto the base paper, wherein the coating layer comprises a) at least one natural wax and/or at least one carboxylic acid component; and b) at least one cellulose derivative as a film-forming agent; wherein the permeability of the coated paper for at least one gas is reduced compared to the base paper.

3. The coated paper according to claim 1, wherein the coating layer further comprises a polymeric stabilizer.

4. The coated paper according to claim 1, wherein the permeability of the coated paper for at least one gas is lower than the permeability of a coated paper with the same base paper and having, respectively, a coating layer of the natural wax or the saturated fatty acid and a coating layer of the natural resin.

5. The coated paper according to claim 1, having a water vapor transmission rate (WVTR) of no more than 50 g.Math.m.sup.2.Math.d.sup.1, preferably no more than 20 g.Math.m.sup.2.Math.d.sup.1, measured at 38 C. and over 90% relative humidity, with a coating weight of 101 g.Math.m.sup.2.

6. The coated paper according to claim 1, wherein the carboxylic acid component is selected from fatty acids, hydroxy fatty acids, or dicarboxylic acids, or esters, amides, or salts thereof.

7. The coated paper according to claim 6, wherein the fatty acids are saturated or unsaturated fatty acids with 12 to 40 carbon atoms, preferably fatty acids with 16 to 18 carbon atoms and 0 or 1 double bond, particularly preferably selected from palmitic acid, margaric acid, stearic acid, wherein the carboxylic acid component is particularly stearic acid or its amide.

8. The coated paper according to claim 1, wherein the natural wax is selected from carnauba wax, candelilla wax, beeswax, Chinese wax, and Japan wax.

9. The coated paper according to claim 2, wherein the polymeric stabilizer is a crosslinked or non-crosslinked stabilizer selected from the group consisting of polyvinyl alcohol, starch, carboxyl group-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol group-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, -isodecyl--hydroxy-poly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymers, acrylic copolymers, and mixtures thereof and mixtures thereof.

10. The coated paper according to claim 2, wherein the coating layer comprises a carboxylic acid component, a natural resin, and optionally a polymeric stabilizer, wherein a) the proportion of the carboxylic acid component, based on the total mass of the coating layer, is in the range of 25 to 75 wt. %, preferably in the range of 30 to 75 wt. %, particularly preferably in the range of 40 to 65 wt. %; b) the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 20 to 60 wt. %, preferably in the range of 25 to 55 wt. %, particularly preferably in the range of 30 to 50 wt. %; and/or b) the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %, preferably in the range of 1 to 15 wt. %, particularly preferably in the range of 2 to 10 wt. %.

11. The coated paper according to claim 2, wherein the coating layer comprises a natural wax, a natural resin, and optionally a polymeric stabilizer, wherein a) the proportion of the natural wax, based on the total mass of the coating layer, is in the range of 40 to 95 wt. %, preferably in the range of 60 to 90 wt. %, particularly preferably in the range of 50 to 85 wt. %, most preferably in the range of 60 to 80 wt. %; b) the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 5 to 60 wt. %, preferably in the range of 10 to 40 wt. %, particularly preferably in the range of 20 to 40 wt. %; and/or b) the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %, preferably in the range of 1 to 15 wt. %, particularly preferably in the range of 2 to 10 wt. %.

12. The coated paper according to claim 1, wherein the coating layer comprises at least one cellulose derivative as a film-forming agent, selected from methylcellulose (MC), ethylcellulose (EC), methylethylcellulose (MEC), hydroxyethylcellulose (HEC), hydroxymethylcellulose (HMC), carboxymethylcellulose (CMC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and hydroxyethylmethylcellulose (HEMC), wherein the coating layer preferably comprises two cellulose derivatives as film-forming agents, wherein the film-forming agents are MC and CMC.

13. The coated paper according to claim 12, wherein the coating layer comprises a carboxylic acid component, two cellulose derivatives as film-forming agents, and at least one polymeric stabilizer, wherein a) the proportion of the carboxylic acid component, based on the total mass of the coating layer, is in the range of 75 to 98 wt. %, preferably in the range of 80 to 95 wt. %, particularly preferably in the range of 85 to 92 wt. %, most preferably in the range of 87 to 90 wt. %; b) the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.2 to 5.0 wt. %, preferably in the range of 0.3 to 2.0 wt. %, particularly preferably in the range of 0.3 to 1.0 wt. %; and/or b) the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %, preferably in the range of 5 to 15 wt. %, particularly preferably in the range of 7 to 13 wt. %.

14. The coated paper according to claim 1, wherein the coating layer comprises a) at least two natural waxes or one natural wax and at least one saturated fatty acid; and b) at least one natural resin.

15. The coated paper according to claim 14, wherein the coating layer comprises two natural waxes, one natural resin, and optionally a polymeric stabilizer, wherein: a) the proportion of the natural waxes, based on the total mass of the coating layer, is in the range of 15 to 60 wt. %, preferably in the range of 25 to 55 wt. %, particularly preferably in the range of 35 to 55 wt. %, most preferably in the range of 40 to 50 wt. %; b) the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 30 to 85 wt. %, preferably in the range of 40 to 70 wt. %, particularly preferably in the range of 45 to 60 wt. %; and/or b) the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %, preferably in the range of 1 to 15 wt. %, particularly preferably in the range of 2 to 10 wt. %.

16. The coated paper according to claim 15, comprising a natural wax, a carboxylic acid component, a natural resin, and optionally a polymeric stabilizer, wherein a) the proportion of the natural wax, based on the total mass of the coating layer, is in the range of 2 to 70 wt. %, preferably in the range of 5 to 35 wt. %, particularly preferably in the range of 5 to 25 wt. %, most preferably in the range of 7 to 20 wt. %; b) the proportion of the carboxylic acid component, based on the total mass of the coating layer, is in the range of 5 to 75 wt. %, preferably in the range of 15 to 70 wt. %, particularly preferably in the range of 25 to 65 wt. %, most preferably in the range of 30 to 40 wt. %; and/or c) the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 5 to 65 wt. %, preferably in the range of 7 to 60 wt. %, particularly preferably in the range of 8 to 55 wt. %; and/or d) the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %, preferably in the range of 1 to 15 wt. %, particularly preferably in the range of 2 to 10 wt. %.

17. The coated paper according to claim 1, wherein the coating layer has a coating weight in the range of 2 to 30 g.Math.m.sup.2, preferably in the range of 5 to 20 g.Math.m.sup.2, particularly preferably in the range of 8 to 15 g.Math.m.sup.2.

18. The coated paper according to claim 1, wherein the coated paper has at least one of the following characteristics: the coated paper is biodegradable, in particular, it has easy biodegradability according to OECD 301; the coated paper is recyclable; and the coated paper can be approved for direct or indirect food contact, in particular according to the guidelines of the European Food Safety Authority.

19. A coating for coating papers, comprising the components as defined in claim 1, and a solvent selected from water, tetrahydrofuran (THF), and ethanol, wherein preferably the solvent is water.

20. A method for producing a coated paper with a base paper and a coating layer, the method comprising the steps of: a) preparing a coating according to claim 19 by melt dispersion, high-pressure dispersion, or spray drying and subsequent mechanical dispersion of the components; b) providing a base paper; c) applying the coating to the base paper, preferably by curtain coating or doctor blade coating; and d) curing the coating to form the coating layer.

21. A packaging comprising the coated paper according to claim 1.

22. The packaging according to claim 21 for use in food packaging, as an insert for electronic components such as silica gel packets, for medical products such as rapid tests, for detergents and cleaning agents, particularly in powder or tablet form.

Description

FIGURES

[0029] FIG. 1 shows a diagram of the measurement results of the Water Vapor Transmission Rate (WVTR) tests of shellac produced according to the invention with binary coating layers of candelilla wax, with a constant coating weight and a varying ratio of shellac to candelilla wax from Example 3.1.

[0030] FIG. 2 shows a diagram of the measurement results of the WVTR tests of shellac produced according to the invention with binary coating layers of candelilla wax, with a constant ratio of shellac to candelilla wax and a varying coating weight from Example 3.1.

[0031] FIG. 3 3 shows a diagram of the results of the WVTR tests over the storage period from Example 3. The papers with the coating consisting of 80% candelilla wax dispersion and 20% shellac were tested after 10, 50, 100, 150, 200, and 250 days of storage.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

[0032] The term coating in the context of the present invention and in accordance with the general understanding in the field of paper technology refers to coating agents containing or consisting of binders, additives, and optionally pigments or matrix pigments, which are applied (coated) onto the paper surface using special coating devices for surface refinement or modification of a base paper. Papers produced in this way are referred to as coated papers.

[0033] In the context of the present invention, a coated paper is understood to be a base paper that includes one or more layers applied by coating, i.e., coating layers. The layers of such a coated paper substrate can be functional layers and structure-forming layers (such as smoothing layers to level the surface).

[0034] The term coating is used in the invention as a generic term for all coatable coating compounds, preparations, and/or solutions in the paper industry for the treatment, modification, or refinement of a paper surface. A coating layer refers to the coating applied and cured on the base paper.

[0035] Paper is a flat material that essentially consists of fibers of plant origin and is formed by draining a fiber suspension on a screen. The resulting fiber web is compressed and dried. In the context of this invention, the flat materials cardboard and paperboard, which are produced in the same way, are also subsumed under paper. The distinction between paper, cardboard, and paperboard is made solely based on the basis weight, with paperboard having a grammage greater than 600 g/m.sup.2, cardboard having a grammage greater than 150 and less than or equal to 600 g/m.sup.2, and paper having a grammage of less than or equal to 150 g/m.sup.2.

[0036] The Water Vapor Transmission Rate (WVTR) is a measurement of the permeability of materials to water vapor. To determine the WVTR value, the amount of water that evaporates through an area of one square meter within 24 hours is measured. The WVTR is expressed as the amount of evaporated water in grams per square meter per day. Unless otherwise specified, the WVTR according to the invention is determined under tropical conditions (38 C., 90% RH) in accordance with DIN 53122-1/DIN 53122-A (rel.: ISO 2528:1995, ASTM E 96). The term water vapor permeability is used synonymously with WVTR.

[0037] In the context of this invention, superhydrophobic surfaces are defined as surfaces with contact angles of 145 or more with respect to water, preferably 150 or more with respect to water. At such high contact angles, typically only about 2 to 3% of the water droplet surface is in contact with the superhydrophobic surface; thus, it has extremely low wettability. Additionally, superhydrophobic surfaces are characterized by a roll-off angle of less than 10.

[0038] In the context of this invention, the contact angle of a liquid droplet on a surface is understood to be the angle formed by the intersection line between the droplet base and the surface with the horizontal. It is measured in degrees and depends on various factors, such as the surface tension of the liquid and the properties of the surface.

[0039] The roll-off angle is understood in this invention to be the inclination angle of a surface at which a droplet rolls off. It is typically used to characterize superhydrophobic surfaces with a very high contact angle, where the droplet is nearly spherical. At smaller contact angles, a droplet can also move off the surface, but it is usually deformed first and then slides over the surface. At a roll-off angle of 180, the water droplet does not roll off but adheres to the coating layer, even if the droplet is hanging downwards.

Coated Paper and Coating

[0040] The present invention, according to the first aspect, relates to a coated paper, comprising a base paper and at least one coating layer applied directly or indirectly onto the base paper, wherein the coating layer comprises [0041] a) at least one natural wax and/or at least one carboxylic acid component; and [0042] b) at least one natural resin; [0043] wherein the permeability of the coated paper for at least one gas is reduced compared to the base paper.

[0044] According to one embodiment of the coated paper, the permeability of the coated paper for at least one gas at the same total application amount is lower than the permeability of a coated paper with the same base paper and a coating layer of the natural resin and a coating layer of a natural wax and/or a carboxylic acid component.

[0045] Due to this effect of the coating layer according to the invention, it is also referred to as a barrier layer.

[0046] By means of the coating layer, the permeability of the coated paper for at least one gas is reduced compared to the base paper. This may be oxygen (O.sub.2), nitrogen (N.sub.2), carbon dioxide (CO.sub.2), methane (CH.sub.4), hydrogen (H.sub.2), water vapor, or mixtures thereof, such as air. In particular, the water vapor transmission rate (WVTR) is reduced.

[0047] It is assumed that by combining at least one natural resin, the crystallization of the natural waxes and carboxylic acid components on the surface is restricted. As a result, improved water vapor barriers are formed, since crystalline structures, while leading to superhydrophobic properties due to the formation of structures on the surface, do not allow the formation of a homogeneous, closed coating, which is required to prevent the permeation of water vapor molecules.

[0048] The surface of the coating layer is therefore not superhydrophobic. The coating layer has a contact angle with water of not more than 150. The contact angle may, for example, be 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, or 145. Surfaces with a contact angle above 145 are still considered superhydrophobic. Accordingly, the contact angle is preferably not more than 145. According to one embodiment, the contact angle is not more than 130. According to one embodiment, the contact angle is not more than 115.

[0049] Furthermore, the coating layer preferably has a roll-off angle of more than 10 with respect to a water droplet of 4 L. The roll-off angle may, for example, be 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, or 180. According to one embodiment, the roll-off angle is more than 20. According to one embodiment, the roll-off angle is more than 40. According to one embodiment, the roll-off angle is more than 60.

[0050] By using the aforementioned bio-based raw materials, a reduction in plastic pollution in the environment is achieved while utilizing raw materials with improved recyclability and biodegradability. Furthermore, as shown in the examples, the use of natural resin can reduce the amount of stabilizer required, which is often poorly biodegradable.

[0051] With the coating layer according to the invention, a coated paper with a high barrier performance, in particular a very low WVTR, can be achieved. According to one embodiment, the WVTR at a coating weight of 101 g.Math.m.sup.2 is not more than 50 g m.sup.2d.sup.1.

[0052] The WVTR of the coated paper according to the invention may, for example, be 50 g m.sup.2d.sup.1, 48 g.Math.m.sup.2.Math.d.sup.1, 46 g.Math.m.sup.2d.sup.1, 44 g.Math.m.sup.2.Math.d.sup.1, 42 g.Math.m.sup.2.Math.d.sup.1, 40 g.Math.m.sup.2.Math.d.sup.1, 38 g.Math.m.sup.2d.sup.1, 36 g.Math.m.sup.2.Math.d.sup.1, 34 g.Math.m.sup.2.Math.d.sup.1, 32 g.Math.m.sup.2.Math.d.sup.1, 30 g.Math.m.sup.2.Math.d.sup.1, 28 g.Math.m.sup.2.Math.d.sup.1, 26 g.Math.m.sup.2d.sup.1, 24 g.Math.m.sup.2.Math.d.sup.1, 22 g.Math.m.sup.2.Math.d.sup.1, 20 g.Math.m.sup.2d.sup.1, 18 g.Math.m.sup.2.Math.d.sup.1, 16 g.Math.m.sup.2.Math.d.sup.1, 14 g m.sup.2d.sup.1, 12 g.Math.m.sup.2.Math.d.sup.1, 10 g.Math.m.sup.2.Math.d.sup.1, 8 g.Math.m.sup.2.Math.d.sup.1, 6 g.Math.m.sup.2d.sup.1, 4 g.Math.m.sup.2.Math.d.sup.1, 2 g.Math.m.sup.2.Math.d.sup.1, 1 g.Math.m.sup.2.Math.d.sup.1. By selecting suitable components for the coating and adjusting the crystallinity, a WVTR of not more than 2020 g.Math.m.sup.2.Math.d.sup.1, or even not more than 10 g.Math.m.sup.2.Math.d.sup.1, can be achieved.

[0053] The natural resin is preferably an organic, chemically/thermally crosslinkable matrix. According to one embodiment, the natural resin is selected from shellac, turpentine, balsam, gum lacquer, colophony, sandarac, mastic, coniferous resin, dammar, gum arabic, and elemi. Preferably, the natural resin is shellac.

[0054] Shellac is a resinous substance obtained from the excretions of the lac insect Kerria lacca (plant lice, family Kerridae) after feeding on specific plants. It consists predominantly (65-75%) of free and esterified aliphatic and aromatic polyhydroxy acids. The main components are aleuritic acid (up to 32%) and shellolic acid. Considering only these main components, a calculated structure shows that three to four molecules are linked together (tri- and tetramers). Since the monomers contain multiple hydroxy and carboxyl groups, they can form three-dimensional networks, similar to those found in thermosetting plastics. Further components include dyes (4-8%), bitter substances, and a small amount of wax (shellac wax; reddish-brown, brittle, very hard, ceryllignocerate, cerylcerotinate, and wax alcohols). Shellac is biodegradable.

[0055] Turpentine is, strictly speaking, more of a volatile oil. It is obtained by distilling resin from coniferous trees, mainly pines. Turpentine consists primarily of terpenes such as -pinene and -pinene. It is used as a solvent and in the manufacture of paints and varnishes. Balsam is an aromatic resin, often mixed with essential oils. It is obtained directly from tree trunks or branches through incisions or natural exudation. Its chemical composition varies but typically contains essential oils and resin acids. Balsam is particularly used in perfumery, medicine, and cosmetics. Gum lacquer is a resin obtained by tapping the bark of various lac trees. It is used in the manufacture of varnishes and paints, as well as in the printing industry, and consists of complex ester and polyphenol compounds.

[0056] Colophony is a resin that is a byproduct of turpentine production, particularly during the distillation of turpentine oil from coniferous resin. It consists mainly of resin acids, such as abietic acid, and is used in electronics for soldering, in the music industry for string instruments, and in chemistry as an adhesive or binder. Sandarac is a resin obtained from various species of cypress trees, particularly by tapping the bark. It is used in the manufacture of varnishes and as incense. Chemically, sandarac consists primarily of terpenoids. Mastic is a resin obtained from the mastic shrub (Pistacia lentiscus), particularly through tapping. Chemically, mastic consists of a mixture of resin acids, essential oils, and resin alcohols. It is used in the food industry as a natural additive and in cosmetics.

[0057] Coniferous resin is a general term for resins produced by coniferous trees such as pines, spruces, and firs. It contains terpenes, resin acids, and sometimes essential oils. Coniferous resins are used in the production of turpentine, varnishes, and adhesives. Dammar is a resin obtained from various tropical tree species, particularly through tapping the bark. Chemically, dammar consists of a mixture of terpenes and resin acids. It is used in varnishes and as an adhesive.

[0058] Gum arabic is a resin obtained from various species of acacia trees, particularly through tapping the bark. Chemically, it is a complex polysaccharide that may also contain proteins. Gum arabic is used as a thickening agent in the food industry and as a binder in the printing industry. Elemi is a resin obtained from tropical trees of the genus Canarium. Chemically, it consists of a mixture of terpenes, resin acids, and essential oils. Elemi is used in the perfume and cosmetics industry.

[0059] Despite their different chemical compositions, these resins share physicochemical properties with shellac and can be used in the same way as shellac as binders, adhesives, or coatings.

[0060] Carboxylic acid components suitable for use according to the invention include, for example, fatty acids, fatty acid amides, fatty acid esters, salts of fatty acids, hydroxy fatty acids, hydroxy fatty acid amides, hydroxy fatty acid esters, salts of hydroxy fatty acids, dicarboxylic acids, as well as their dicarboxylic acid esters, dicarboxylic acid amides, or salts of dicarboxylic acids. Examples of dicarboxylic acids suitable for use according to the invention include tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid, and docosanedioic acid

[0061] The carboxylic acid component may be a saturated or unsaturated fatty acid with 12 to 40 carbon atoms. Examples of saturated fatty acids include lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, lacceric acid, and geddic acid. Examples of unsaturated fatty acids include myristoleic acid, palmitoleic acid, margroleic acid, petroselinic acid, oleic acid (OA), elaidic acid, vaccenic acid, gadoleic acid, gondolic acid, cetoleic acid, erucic acid, and nervonic acid. Examples of polyunsaturated fatty acids include linoleic acid (LA), -linolenic acid (ALA), -linolenic acid (GLA), calendic acid, punicic acid, alpha-eleostearic acid, beta-eleostearic acid, stearidonic acid, arachidonic acid, eicosapentaenoic acid (timnodonic acid, EPA), docosadienoic acid, docosatetraenoic acid (adrenic acid, ADA), docosapentaenoic acid (clupanodonic acid, DPA-3), docosahexaenoic acid (cervonic acid, clupanodonic acid, DHA), and tetracosahexaenoic acid (nisinic acid)

[0062] According to one embodiment, the fatty acid used as the carboxylic acid component has 16 to 18 carbon atoms and 0 or 1 carbon-carbon double bond. According to one embodiment, the fatty acid is selected from margaric acid, stearic acid, palmitic acid, linoleic acid, -linolenic acid, and -linolenic acid. According to one embodiment, the carboxylic acid component is stearic acid or its amide or salt.

[0063] Fatty acid salts according to the invention are chromium (III) chloride complexes with fatty acids, as well as aluminum, calcium, sodium, potassium, and ammonium salts. Preferred fatty acid salts are monovalent salts derived from sodium, potassium, or ammonium ions.

[0064] According to one embodiment, the fatty acid component is a fatty acid mixture. According to one embodiment, the fatty acid mixture is a mixture of stearic acid, palmitic acid, oleic acid, linoleic acid, and/or linolenic acid. Further examples of fatty acid mixtures include a mixture of stearic acid and palmitic acid, a mixture of stearic acid, palmitic acid, and oleic acid, a mixture of stearic acid, linoleic acid, and linolenic acid, a mixture of stearic acid, palmitic acid, and linoleic acid, a mixture of stearic acid, palmitic acid, and linolenic acid, a mixture of stearic acid, oleic acid, and linoleic acid, a mixture of stearic acid, oleic acid, and linolenic acid, and a mixture of stearic acid, linoleic acid, and linolenic acid. A preferred mixture is a mixture of stearic acid and palmitic acid.

[0065] Waxes suitable for use according to the invention include, among others, carnauba wax, candelilla wax, beeswax, Chinese wax, and Japan wax. The wax is preferably carnauba wax or candelilla wax.

[0066] According to one embodiment, the polymeric stabilizer is a crosslinked or non-crosslinked stabilizer. The polymeric stabilizer prevents the agglomeration of finely dispersed coating components. The stabilizer may also act as a binder when used in larger amounts. The polymeric stabilizer may be selected from the group consisting of polyvinyl alcohol, starch, carboxyl group-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol group-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, -isodecyl-w-hydroxy-poly(oxy-1,2-ethanediy), styrene-butadiene latex, styrene-acrylate polymers, acrylic copolymers, carboxyl group-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol group-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, -isodecyl-w-hydroxy-poly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymers, acrylic copolymers, and mixtures thereof and mixtures thereof. According to one embodiment, the polymeric stabilizer is polyvinyl alcohol. Polyvinyl alcohol is commercially available in various degrees of hydrolysis and viscosities. Preferably, polyvinyl alcohols with a viscosity of 2-10 mPas (measured as a 4% aqueous solution at 20 C. according to DIN 53015/JIS K 6) and a degree of hydrolysis of >80 mol % are used. Commercially available examples include KURARAY POVAL 6-88 and KURARAY POVAL 6-98.

[0067] According to one embodiment, the coating layer comprises a carboxylic acid component, a natural resin, and optionally a polymeric stabilizer. In this composition, the proportion of the carboxylic acid component, based on the total mass of the coating layer, may be in the range of 15 to 85 wt. %. For example, the carboxylic acid component may be present in an amount of 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, or 85 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 25 to 75 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 30 to 75 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 40 to 65 wt. %.

[0068] In the binary composition of the coating layer comprising a carboxylic acid component, a natural resin, and optionally a polymeric stabilizer, the proportion of the natural resin, based on the total mass of the coating layer, may be in the range of 10 to 70 wt. %. For example, the natural resin may be present in an amount of 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, or 70 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 20 to 60 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 25 to 55 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 30 to 50 wt. %.

[0069] In the composition of the coating layer comprising a carboxylic acid component, a natural resin, and a polymeric stabilizer, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, may be below 30 wt. %. For example, the polymeric stabilizer may be present in an amount of 0.1 wt. %, 0.5 wt. %, 1 wt. %, 1.5 wt. %, 2.0 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 12 wt. %, 14 wt. %, 16 wt. %, 18 wt. %, 20 wt. %, 22 wt. %, 24 wt. %, 26 wt. %, or 28 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 1 to 15 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 2 to 10 wt. %.

[0070] According to one embodiment, the binary coating layer comprises a natural wax, a natural resin, and optionally a polymeric stabilizer. In this composition, the proportion of the natural wax, based on the total mass of the coating layer, may be in the range of 15 to 95 wt. %. For example, the natural wax may be present in an amount of 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, 85 wt. %, 90 wt. %, or 95 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 30 to 95 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 40 to 90 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 50 to 85 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 60 to 80 wt. %.

[0071] In the composition of the coating layer comprising natural wax, natural resin, and optionally a polymeric stabilizer, the proportion of the natural resin, based on the total mass of the coating layer, may be in the range of 5 to 70 wt. %. For example, the natural resin may be present in an amount of 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, or 70 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 5 to 60 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 10 to 40 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 20 to 40 wt. %.

[0072] In the composition of the coating layer comprising natural wax, natural resin, and a polymeric stabilizer, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, may be below 30 wt. %. For example, the polymeric stabilizer may be present in an amount of 0.1 wt. %, 0.5 wt. %, 1 wt. %, 1.5 wt. %, 2.0 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 12 wt. %, 14 wt. %, 16 wt. %, 18 wt. %, 20 wt. %, 22 wt. %, 24 wt. %, 26 wt. %, or 28 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 1 to 15 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 2 to 10 wt. %.

[0073] According to one embodiment, the coating layer comprises at least one film-forming agent. The film-forming agent is in particular a cellulose derivative. The cellulose derivative may be selected from methylcellulose (MC), ethylcellulose (EC), methylethylcellulose (MEC), hydroxyethylcellulose (HEC), carboxymethylcellulose (CMC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and hydroxyethylmethylcellulose (HEMC). According to one embodiment, the coating layer comprises one, two, three, four, five, six, seven, eight, nine, or ten film-forming agents. According to one embodiment, the coating layer comprises the film-forming agents methylcellulose and carboxymethylcellulose.

[0074] According to one embodiment, the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.2 to 5.0 wt. %. For example, the film-forming agents may be present in an amount of 0.2 wt. %, 0.4 wt. %, 0.6 wt. %, 0.8 wt. %, 1.0 wt. %, 1.2 wt. %, 1.4 wt. %, 1.6 wt. %, 1.8 wt. %, 2.0 wt. %, 2.4 wt. %, 2.8 wt. %, 3.0 wt. %, 3.4 wt. %, 3.8 wt. %, 4.0 wt. %, 4.4 wt. %, 4.8 wt. %, or 5.0 wt. %. According to one embodiment, the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.3 to 2.0 wt. %. According to one embodiment, the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.3 to 1.0 wt. %.

[0075] With the film-forming agents according to the invention, comparable properties with respect to barrier effects against gases and moisture could surprisingly also be achieved for a coated paper, even when omitting the natural resin. Accordingly, in a second aspect, the invention relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly onto the base paper, wherein the coating layer comprises [0076] a) at least one natural wax and/or at least one carboxylic acid component, and [0077] b) at least one film-forming agent, in particular a cellulose derivative; [0078] wherein the permeability of the coated paper for at least one gas is reduced compared to the base paper.

[0079] The film-forming agent is thus used in place of the natural resin. Apart from this, the coating layer of the coated paper according to the second aspect, unless otherwise defined, has the same features as the coating layer of the coated paper according to the first aspect.

[0080] According to one embodiment, the coating layer comprises a carboxylic acid component, at least two film-forming agents, in particular cellulose derivatives, and at least one polymeric stabilizer.

[0081] In this composition, the proportion of the carboxylic acid component, based on the total mass of the coating layer, may be in the range of 75 to 98 wt. %. For example, the carboxylic acid component may be present in an amount of 75 wt. %, 76 wt. %, 77 wt. %, 78 wt. %, 79 wt. %, 80 wt. %, 81 wt. %, 83 wt. %, 84 wt. %, 85 wt. %, 86 wt. %, 87 wt. %, 88 wt. %, 89 wt. %, 90 wt. %, 91 wt. %, 93 wt. %, 94 wt. %, 95 wt. %, 96 wt. %, 97 wt. %, or 98 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 85 to 92 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 87 to 90 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 40 to 65 wt. %.

[0082] In the composition of the coating layer comprising a carboxylic acid component, two film-forming agents, and optionally a polymeric stabilizer, the proportion of the film-forming agents, based on the total mass of the coating layer, may be in the range of 0.2 to 5.0 wt. %. For example, the film-forming agents may be present in an amount of 0.2 wt. %, 0.4 wt. %, 0.6 wt. %, 0.8 wt. %, 1.0 wt. %, 1.2 wt. %, 1.4 wt. %, 1.6 wt. %, 1.8 wt. %, 2.0 wt. %, 2.4 wt. %, 2.8 wt. %, 3.0 wt. %, 3.4 wt. %, 3.8 wt. %, 4.0 wt. %, 4.4 wt. %, 4.8 wt. %, or 5.0 wt. %. According to one embodiment, the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.3 to 2.0 wt. %. According to one embodiment, the proportion of the film-forming agents, based on the total mass of the coating layer, is in the range of 0.3 to 1.0 wt. %.

[0083] In the composition of the coating layer comprising a carboxylic acid component, a natural resin, and a polymeric stabilizer, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, may be below 30 wt. %. For example, the polymeric stabilizer may be present in an amount of 0.1 wt. %, 0.5 wt. %, 1 wt. %, 1.5 wt. %, 2.0 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 12 wt. %, 14 wt. %, 16 wt. %, 18 wt. %, 20 wt. %, 22 wt. %, 24 wt. %, 26 wt. %, or 28 wt. %. Compared to barrier layers containing natural resin, it is advantageous if the proportion of the polymeric stabilizer is higher. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 5 to 15 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 7 to 13 wt. %.

[0084] According to one embodiment of the coated paper according to the first aspect, the coating layer is a ternary coating layer, meaning a coating layer that comprises at least two natural waxes or at least one natural wax and one saturated fatty acid, and at least one natural resin. In the ternary systems according to the invention, the proportion of the polymeric stabilizer can be further reduced. Furthermore, directly overcoatable layers can be produced. By varying the composition of the coating layer, it is possible to adjust for the availability of individual components while maintaining a constant barrier performance (WVTR). Finally, the temary coating layers also exhibit grease resistance.

[0085] According to one embodiment of the coated paper according to the first aspect, the coating layer comprises two natural waxes, one natural resin, and optionally a polymeric stabilizer. In this composition, the proportion of the natural waxes, based on the total mass of the coating layer, may be in the range of 10 to 80 wt. %. For example, the natural waxes may be present in an amount of 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, or 80 wt. %. According to one embodiment, the proportion of the natural waxes is in the range of 15 to 60 wt. %. According to one embodiment, the proportion of the natural waxes is in the range of 25 to 55 wt. %. According to one embodiment, the proportion of the natural waxes is in the range of 35 to 55 wt. %. According to one embodiment, the proportion of the natural waxes is in the range of 40 to 50 wt. %.

[0086] In the composition of the coating layer comprising two natural waxes, a natural resin, and optionally a polymeric stabilizer, the proportion of the natural resin, based on the total mass of the coating layer, may be in the range of 20 to 90 wt. %. For example, the natural resin may be present in an amount of 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %. 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, 85 wt. %, or 90 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 30 to 85 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 40 to 70 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 45 to 60 wt. %.

[0087] In the composition of the coating layer comprising two natural waxes, a natural resin, and a polymeric stabilizer, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, may be below 30 wt. %. For example, the polymeric stabilizer may be present in an amount of 0.1 wt. %, 0.5 wt. %, 1 wt. %, 1.5 wt. %, 2.0 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 12 wt. %, 14 wt. %, 16 wt. %, 18 wt. %, 20 wt. %, 22 wt. %, 24 wt. %, 26 wt. %, or 28 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 1 to 15 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 2 to 10 wt. %.

[0088] According to one embodiment, the ternary coating layer comprises a carboxylic acid component, a natural wax, a natural resin, and optionally a polymeric stabilizer. In this composition, the proportion of the carboxylic acid component, based on the total mass of the coating layer, is preferably in the range of 5 to 85 wt. %. For example, the carboxylic acid component may be present in an amount of 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, or 85 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 55 to 75 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 15 to 70 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 25 to 65 wt. %. According to one embodiment, the proportion of the carboxylic acid component is in the range of 30 to 40 wt. %.

[0089] In this composition, the proportion of the natural wax, based on the total mass of the coating layer, may be in the range of 15 to 95 wt. %. For example, the carboxylic acid component may be present in an amount of 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, 85 wt. %, 90 wt. %, or 95 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 30 to 95 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 40 to 90 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 50 to 85 wt. %. According to one embodiment, the proportion of the natural wax is in the range of 60 to 80 wt. %.

[0090] In the composition of the coating layer comprising a carboxylic acid component, a natural wax, a natural resin, and optionally a polymeric stabilizer, the proportion of the natural resin, based on the total mass of the coating layer, may be in the range of 5 to 70 wt. %. For example, the natural resin may be present in an amount of 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, or 70 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 20 to 60 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 25 to 55 wt. %. According to one embodiment, the proportion of the natural resin, based on the total mass of the coating layer, is in the range of 30 to 50 wt. %.

[0091] In the composition of the coating layer comprising a carboxylic acid component, a natural wax, a natural resin, and a polymeric stabilizer, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, may be below 30 wt. %. For example, the polymeric stabilizer may be present in an amount of 0.1 wt. %, 0.5 wt. %, 1 wt. %, 1.5 wt. %, 2.0 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 12 wt. %, 14 wt. %, 16 wt. %, 18 wt. %, 20 wt. %, 22 wt. %, 24 wt. %, 26 wt. %, or 28 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is below 20 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 1 to 15 wt. %. According to one embodiment, the proportion of the polymeric stabilizer, based on the total mass of the coating layer, is in the range of 2 to 10 wt. %.

[0092] The coating layer in the coated paper may have a coating weight in the range of 2 to 30 g.Math.m.sup.2. For example, the coating weight may be 2 g.Math.m.sup.2, 4 g.Math.m.sup.2, 5 g.Math.m.sup.2, 6 g.Math.m.sup.2, 8 g.Math.m.sup.2, 10 g.Math.m.sup.2, 12 g m.sup.2, 14 g.Math.m.sup.2, 15 g.Math.m.sup.2, 16 g.Math.m.sup.2, 18 g m.sup.2, 20 g m.sup.2, 22 g.Math.m.sup.2, 24 g.Math.m.sup.2, 25 g.Math.m.sup.2, 26 g.Math.m.sup.2, 28 g.Math.m.sup.2, or 30 g.Math.m.sup.2. According to one embodiment, the coating layer has a coating weight in the range of 2 to 30 g.Math.m.sup.2. According to one embodiment, the coating layer has a coating weight in the range of 5 to 20 g.Math.m.sup.2 According to one embodiment, the coating layer has a coating weight in the range of 8 to 15 g.Math.m.sup.2.

[0093] Due to the materials present in the coating layer, the coated paper according to the first or second aspect is biodegradable. Biodegradability refers to the ability of organic chemicals to be decomposed biologically, i.e., by living organisms or their enzymes. Ideally, this chemical metabolism proceeds completely to mineralization, but it can also stop at degradation-resistant transformation products. The OECD guidelines for testing chemicals, which are also used in the context of chemical approval, are generally recognized. The tests in the OECD test series 301 (A-F) demonstrate rapid and complete biodegradation (ready biodegradability) under aerobic conditions. Different test methods are available for well or poorly soluble as well as volatile substances. Biodegradable or biologically degradable within the meaning of the present invention refers to papers that exhibit biodegradability measured according to OECD 301 F of at least 40% or measured according to OECD 302 C (MITI-II test) of at least 20%, thus exhibiting inherent or basic biodegradability. This corresponds to the limit for OECD 302 C according to the Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3, Part 1, dated 23 Mar. 2006. From a threshold of at least 60% measured according to OECD 301 F, papers are also referred to as rapidly biodegradable.

[0094] According to one embodiment, the coated paper exhibits easy biodegradability according to OECD 301.

[0095] Furthermore, the coated paper according to the first or second aspect is recyclable. Paper recycling refers to the dissolution and processing of waste paper, used cardboard, and paperboard in paper industry facilities with the goal of producing new paper, cardboard, and paperboard. To a lesser extent, waste paper is first converted into recycled paper pulp, which is then used to manufacture new paper. Deinking, the process of removing printing ink from printed waste paper, is a key process in paper recycling. The recyclability evaluation can be carried out using the INGEDE Method 11. The coated paper according to the invention achieves a deinkability score of over 50 using the INGEDE Method 11. Preferably, the deinkability score is over 70.

[0096] With the components used in the barrier layer according to the first or second aspect, the coated paper can be approved for direct or indirect food contact. In particular, it is suitable for approval in accordance with the guidelines of the European Food Safety Authority.

[0097] As the base paper for the coated paper according to the first or second aspect, all types of paper can generally be used, including board, cardboard, or regular paper. Preferably, papers made from hardwood and softwood pulps are used. For food packaging, papers with low grammage are often in demand, as they are flexible and material-efficient. Particularly for such papers, the coating layer according to the invention leads to a significant increase in barrier performance.

[0098] According to one embodiment of the coated paper according to the first or second aspect, the base paper has a basis weight of less than 150 g.Math.m.sup.2. The basis weight may be, for example, 150 g.Math.m.sup.2, 145 g.Math.m.sup.2, 140 g.Math.m.sup.2, 135 g.Math.m.sup.2, 130 g.Math.m.sup.2, 125 g.Math.m.sup.2, 120 g.Math.m.sup.2, 115 g.Math.m.sup.2, 110 g.Math.m.sup.2, 105 g.Math.m.sup.2, 100 g.Math.m.sup.2, 95 g.Math.m.sup.2, 90 g.Math.m.sup.2, 85 g.Math.m.sup.2, 80 g.Math.m.sup.2, 75 g.Math.m.sup.2, 70 g.Math.m.sup.2, 65 g.Math.m.sup.2, 60 g.Math.m.sup.2, 55 g.Math.m.sup.2, 50 g.Math.m.sup.2, 45 g.Math.m.sup.2, 40 g m.sup.2, 35 g.Math.m.sup.2, or 30 g.Math.m.sup.2. According to one embodiment, the basis weight is below 100 g.Math.m.sup.2. According to one embodiment, the basis weight is below 80 g.Math.m.sup.2. According to one embodiment, the basis weight is in the range of 50 to 80 g.Math.m.sup.2.

[0099] The coated paper according to the first or second aspect may contain additional layers in addition to the barrier layer. According to one embodiment, the coated paper comprises an additional layer selected from a coating, an ink, a sealing medium, and an adhesive.

[0100] The additional layer may be arranged on the barrier layer, between the base paper and the barrier layer, or on the side of the base paper opposite the semi-crystalline coating layer.

[0101] The barrier layer may therefore be applied directly onto the base paper. In this case, the barrier layer is in direct contact with the base paper. Indirect application means that one or more layers are present between the coating and the base paper.

[0102] Additional layers can particularly further reduce the permeability of the coated paper for at least one gas compared to the base paper or form barriers for liquids or viscous substances such as fats, oils, or hydrocarbons.

[0103] An additional layer may, in particular: [0104] a) comprise at least one hydrophobic polymer, e.g., based on a polyacrylate, a styrene-butadiene copolymer, and/or a polyolefin; [0105] b) comprise at least one hydrophilic polymer, e.g., based on a polyvinyl alcohol; [0106] c) comprise at least one inorganic pigment, e.g., a platelet-shaped pigment, such as a layered silicate like kaolin; [0107] d) comprise at least one inorganic pigment and a binder; [0108] e) comprise amorphous and crystalline regions; [0109] f) contain or consist of substances selected from the group of lipophilic substances, paraffins, in particular hard paraffins, waxes, in particular microcrystalline waxes, waxes based on vegetable oils or fats, waxes based on animal oils or fats, vegetable waxes, animal waxes, low-molecular-weight polyolefins, polyterpenes, and mixtures thereof; [0110] g) reduce or prevent the migration of substances, in particular hydrophobic substances, e.g., substances according to item f), to, for example, prevent or reduce the migration of substances from underlying layers into a food product, in particular a fat-containing food product; [0111] h) comprise or consist of at least one metal, e.g., aluminum, gold, and/or a metal oxide, e.g., aluminum oxide, in particular forming a metallized layer; [0112] i) be at least heat- or cold-sealable; [0113] j) comprise at least one adhesive; [0114] k) comprise or consist of at least one thermoplastic material, in particular as a heat-sealable material.

[0115] The base paper of the coated paper according to the first or second aspect may be a single- or double-sided coated base paper or an uncoated base paper.

[0116] For coated base paper, the surface is refined with a binder-containing coating. The coating material used for the binder application may primarily comprise starch, starch derivatives, chalk, kaolin, casein, or plastic dispersion. This process results in the base paper having a more closed, smoother, and more stable surface.

[0117] However, uncoated base paper may also be surface-treated and contain up to 5 g/m.sup.2 of pigments.

[0118] For use as packaging in the food sector, the paper requires a certain tensile strength or breaking strength. According to one embodiment, the coated paper has a tensile strength in the fiber direction ranging from 3.0 bis 6.0 kN.Math.m.sup.1. The tensile strength in the fiber direction can be, for example, 3.0 kN.Math.m.sup.1, 3.2 kN.Math.m.sup.1, 3.4 kN.Math.m.sup.1, 3.5 kN.Math.m.sup.1, 3.6 kN.Math.m.sup.1, 3.8 kN.Math.m.sup.1, 4.0 kN.Math.m.sup.1, 4.2 kN.Math.m.sup.1, 4.4 kN.Math.m.sup.1, 4.5 kN.Math.m.sup.1, 4.6 kN.Math.m.sup.1, 4.8 kN.Math.m.sup.1, 5.0 kN.Math.m.sup.1, 5.2 kN.Math.m.sup.1, 5.4 kN.Math.m.sup.1, 5.5 kN.Math.m.sup.1, 5.6 kN.Math.m.sup.1, 5.8 kN.Math.m.sup.1, 6.0 kN.Math.m.sup.1. According to one embodiment, the tensile strength in the fiber direction ranges from 3.5 bis 5.5 kN m.sup.1. According to another embodiment, the tensile strength in the fiber direction ranges from 4.0 bis 5.0 kN m.sup.1.

[0119] The barrier performance of the coating layer according to the invention is achieved with a coating layer as defined in the first aspect.

[0120] Consequently, in a third aspect, the invention relates to a coating for coating papers, comprising the components defined according to the first or second aspect, as well as a solvent. Particularly, the solvent is selected from water, tetrahydrofuran (THF), ethanol, methanol, and ethyl acetate. Preferably, the solvent is water.

Manufacturing Process

[0121] Various manufacturing methods can be used for producing the coated paper according to the invention. The essential barrier performance of the coating layer in the coated paper is particularly achieved with the method for producing the coated paper as shown in the examples. Accordingly, in a fourth aspect, the invention relates to a method for producing a coated paper with a base paper and a coating layer, comprising the steps: [0122] a) preparing a coating according to the third aspect by mixing the individual components; [0123] b) providing a base paper; [0124] c) applying the coating onto the base paper; and [0125] d) curing the coating, forming the coating layer with barrier performance.

[0126] According to one embodiment, the application of the coating onto the base paper is preferably carried out by curtain coating or doctor blade coating.

[0127] With the method according to the invention, it is possible to influence the properties of the coating layer.

[0128] Furthermore, the curing temperature, curing time, and curing pressure influence the homogeneity and barrier performance

[0129] According to one embodiment of the method, the curing temperature is in the range of 20 to 300 C. The curing temperature may be 20 C., 40 C., 60 C., 80 C., 90 C., 100 C. 110 C. 120 C., 130 C., 140 C., 150 C., 160 C., 170 C., 180 C., 190 C., 200 C., 220 C., 240 C., 260 C., 280 C., or 300 C. According to one embodiment of the method, the curing temperature is in the range of 100 to 140 C. According to one embodiment of the method, the curing temperature is in the range of 110 to 130 C.

[0130] According to one embodiment of the method, the curing time is in the range of 10 s to 15 min. The curing time may be 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 120 s, 150 s, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min. According to one embodiment of the method, the curing time is in the range of 1 to 3 min.

[0131] According to one embodiment of the method, the curing pressure is in the range of 0.2 bar to 3 bar. According to one embodiment of the method, the curing pressure is in the range of 0.9 bar to 1.1 bar.

Packaging

[0132] In a fifth aspect, the invention relates to packaging comprising the coated paper according to the first or second aspect.

[0133] This may, for example, be packaging for use in food packaging, as an insert for electronic components such as silica gel packets, for medical products such as rapid tests, for detergents and cleaning agents, particularly in powder or tablet form

[0134] Furthermore, it may be packaging for dried food, chilled food requiring further preparation, packaging containing food in portion sizes for more than one person, or packaging with food in portion sizes for a single person where more than one unit is sold.

[0135] Examples of packaging include stand-up pouch packaging, pillow bag packaging, or packaging paper. According to one embodiment, the packaging is a pillow bag packaging.

EXAMPLES

Example 1-Raw Materials and Production of the Coatings and Barrier Papers

Substrate

[0136] In all examples, Clay Coated Kraft (CCK) paper, i.e., a clay-coated paper (coating weight: 5 g/m.sup.2) made from hardwood and softwood pulps with a total basis weight of 63 g/m.sup.2, was used as the substrate.

Preparation of Raw Materials

[0137] All waxes and carboxylic acid derivatives were used as aqueous dispersions, stabilized by the addition of polyvinyl alcohol (approx. 10 wt. %; viscosity: 6-9 mPas; 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol %).

[0138] The dry content (DC) of the dispersions was adjusted by adding water as follows: Candelilla wax (44%), Carnauba wax (40%), Stearic acid (25%), Palmitic acid (25%), Stearamide (25%).

[0139] Shellac (Swanlac ASL 10, deparaffinized and decolorized) was dissolved in ammoniacal water (DC=25%).

[0140] Methylcellulose (MC) and Hydroxypropylmethylcellulose (HPMC) were used as solids.

[0141] Polyethylene glycol (PEG) 400 was used without prior treatment.

Production of the Coatings

[0142] The dry content of the coatings was between 23% and 40%, depending on the system. No additional water was added after mixing the component dispersions. The coatings were sieved through an 80 m mesh screen and degassed using a Hauschild SpeedMixer for 4 min at 30 mbar and 800 rpm.

Coating of the Base Papers

[0143] The coating (3-5 mL per DIN A4 application) was applied with a film applicator using squeegee bars (Erichsen) at room temperature to the CCK-coated side of the base papers (DIN A3). The wire-wound rod was selected to achieve the desired coating weight of 10 g/m.sup.2. The specified coating weight refers to the dry layer.

[0144] After coating, the papers were immediately fixed with magnets on standard cardboard (to prevent curling) and dried in a circulating air oven (Memmert; setting: 50% damper, 50% fan) at 110 C. until the barrier film was fully formed.

Example 2Barrier Performance of Comparative Coatings with a Single Component

[0145] First, coatings composed of individual componentscarboxylic acid components (fatty acids and their derivatives), wax, and natural resin (shellac)were tested for their water vapor barrier performance.

[0146] For this purpose, coatings with the following compositions were prepared according to the description in Example 1: [0147] Shellac dissolved in ethanol (25 wt. %) [0148] Shellac dissolved in glacial acetic acid (25 wt. %) [0149] Shellac dissolved in 5 wt. % ammonium bicarbonate solution (25 wt. %) [0150] Candelilla wax dispersion (26 wt. %) [0151] Carnauba wax dispersion (26 wt. %) [0152] Palmitic acid dispersion (25 wt. %) [0153] Stearic acid dispersion (25 wt. %) [0154] Stearamide dispersion (25 wt. %)

[0155] To produce coated papers, the coatings were applied to the pre-coated base paper, as described in Example 1. The coating weight was 10 g/m.sup.2 in each case. The drying time was approximately 1-1.5 minutes at a temperature of approximately 110 C.

[0156] The water vapor transmission rate (WVTR) was determined under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96). The results of this measurement are presented in Table 1.

TABLE-US-00001 TABLE 1 WVTR of Comparative Barrier Papers with Coating Layers Composed of Single Components Coating composition WVTR (g/m.sup.2d) (pre-coated base paper) 990 38 shellac dissolved in ethanol (25 wt. %) 239 2 dissolved in glacial acetic acid (25 wt. %) 242 8 dissolved in 5 wt. % ammonium bicarbonate solution 201 10 (25 wt. %) wax candelilla wax 78 11 carnauba wax 90 2 fatty acid + fatty acid derivatives palmitic acid 68 16 stearic acid 44 0.3 stearamide 71 2.5

[0157] A barrier paper with a coating consisting solely of shellac exhibits only low water vapor barrier performance, as indicated by WVTR values exceeding 200 g/m.sup.2.d. In contrast, the WTR of barrier papers with layers of natural waxes and fatty acids/fatty acid derivatives is significantly lower. However, especially with coatings containing fatty acids, inhomogeneous film formation occurs, leading to fluctuations in WVTR across the surface of the barrier paper.

Example 3Characterization of Binary Coatings According to the Invention

3.1 Binary Coating Composed of Shellac and Candelilla Wax

3.1.1. Application Using a Doctor Blade

[0158] In this test series, binary coatings composed of shellac and candelilla wax were examined for their water vapor barrier performance.

[0159] For this purpose, coatings with different ratios of shellac and candelilla wax, as well as PVA (6-9 mPas viscosity, 4% aqueous solution, degree of hydrolysis: 86.7-88.7 mol %), were prepared according to the description in Example 1. The formulations had a candelilla wax dispersion-to-shellac ratio of 0:100, 20:80, 40:60, 60:40, 80:20, and 100:0.

[0160] To produce coated papers, the coatings were applied to the base paper as described in Example 1. The coating weight was 10 g/m.sup.2.

[0161] Additionally, the formulation with a candelilla wax dispersion-to-shellac ratio of 20:80 was applied with varying coating weights in the range of 5 to 30 g/m.sup.2.

[0162] In the examples, drying was carried out at a constant temperature between 90-120 C. for a defined period. The drying time was kept as short as possible, meaning only until the film was fully formed (visually identified by a uniform gloss), without additional annealing. Annealing refers to the uniform heating of a material below the melting temperature over an extended period (from several minutes to several hours). Prolonged drying results in impregnation, which negatively affects the barrier performance of the coated papers. In this case, the drying time was approximately 1-1.5 minutes at a temperature of about 110 C.

[0163] The water vapor transmission rate (WVTR) was determined using the cup method under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96).

[0164] The results are presented in FIGS. 1 and 2.

[0165] By combining shellac with wax dispersions, the film formation and drying properties during the application of the coating onto the substrate paper were improved. Additionally, the binary coating layers exhibited an enhanced WVTR at a coating weight of 10 g/m.sup.2 compared to single-component layers For WVTR, a minimum value was identified at a shellac-to-Candelilla wax ratio of 1:4 (20:80) by varying the proportions of shellac and wax. Furthermore, mixing the wax dispersion with shellac allows for a reduction in the process-related polyvinyl alcohol (PVA) content.

[0166] The coating weight also had a significant impact on WVTR. When reducing the coating weight to 5 g/m.sup.2, the WVTR increased from approximately 40 g/m.sup.2.d to over 80 g/m.sup.2.d. Conversely, increasing the coating weight made it possible to achieve WVTR values close to 0 g/m.sup.2.d. The minimum WVTR was observed at coating weights of approximately 15 g/m.sup.2.

3.1.2. Application Using Curtain Coating

[0167] By adding process additives known to the skilled person (e.g., thickeners and surfactants), a coating according to the invention composed of 80% candelilla wax dispersion and 20% shellac solution was successfully applied and dried using the curtain coating method at a coating machine operating speed of at least 200 m/min. The resulting coated papers exhibited a WVTR of 27.42.0 g/m.sup.2.d

3.1.3. Storage Stability

[0168] The coated papers produced according to 3.1.2, with a coating layer composed of candelilla wax dispersion and shellac, were examined for storage stability.

[0169] The papers were tested for water vapor barrier performance after 10, 75, 100, 150, and 200 days of storage at 23 C. and 50% relative humidity.

[0170] The results are presented in FIG. 3.

3.2 Binary Coating Composed of Shellac and Stearic Acid

[0171] In this test series, binary coatings composed of shellac and stearic acid were examined for their water vapor barrier performance.

[0172] For this purpose, coatings with different ratios of shellac and stearic acid were prepared according to the description in Example 1. The exact compositions are provided in Table 2.

[0173] To produce coated papers, the coatings were applied to the base paper, as described in Example 1. The coating weight was 10 g/m.sup.2.

[0174] The drying time was approximately 2-2.5 minutes at a temperature of approximately 90 C.

[0175] The WVTR was determined under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96). The results are presented in Table 2.

TABLE-US-00002 TABLE 2 WVTR of Binary Barrier Papers According to the Invention shellac (%):stearic acid dispersion (DC = 25%) WVTR (g/m.sup.2d) 52.1 50:50 55 6 31.8 30:70 46 5 27.2 25:75 15 1 11.1 10:90 35 3

[0176] In the production of binary coating layers composed of shellac and stearic acid, improved film formation and drying properties were observed compared to single-component layers. Additionally, at a coating weight of 10 g/m.sup.2, the binary coating layers exhibited a lower WVTR compared to single-component layers. It is assumed that the incorporation of shellac limits the crystallization of stearic acid on the surface, leading to an improved water vapor barrier and a more homogeneous coating For WVTR, a minimum value was identified at a shellac-to-stearic acid ratio of approximately 1:3 (25:75) by varying the proportions of shellac and stearic acid dispersion. Furthermore, mixing stearic acid with shellac allows for a reduction in process-related polyvinyl alcohol (PVA) content.

3.3 Binary Coating Composed of Shellac and Stearamide

[0177] In this test series, binary coatings composed of shellac and stearamide were examined for their water vapor barrier performance.

[0178] For this purpose, coatings with different ratios of shellac and stearamide, as well as PVA (6-9 mPas in a 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol %), were prepared according to the description in Example 1. The formulations had a shellac-to-stearamide dispersion ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 0:100.

[0179] To produce coated papers, the coatings were applied to the base paper, as described in Example 1. The coating weight was 10 g/m.sup.2.

[0180] Additionally, the formulation with a shellac-to-stearamide dispersion ratio of 50:50 was applied with varying coating weights in the range of 1 to 20 g/m.sup.2.

[0181] In the examples, drying was carried out at a constant temperature of 130 C. for a defined period. The drying time was kept as short as possible, meaning only until the film was fully formed (visually identified by a uniform gloss), without additional annealing. Prolonged drying results in impregnation, which negatively affects the barrier performance of the coated papers. In this case, the drying time was approximately 2-3 minutes at a temperature of about 130 C.

[0182] The water vapor transmission rate (WVTR) was determined using the cup method under tropical conditions (38 C. 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96).

[0183] The results are presented in Tables 3 and 4.

TABLE-US-00003 TABLE 3 WVTR of Barrier Papers According to the Invention With a Binary Coating Composed of Shellac and Stearamide Dispersion in Different Ratios at a Coating Weight of 10 g/m.sup.2 shellac (%):stearamide dispersion (%) (DC = 25%) WVTR.sub.Trop. (g/m.sup.2d) 100:0 249 10 80:20 67 12 70:30 61 9 60:40 57 2 50:50 53 3 40:60 73 4 30:70 90 17 20:80 58 7 0:100 71 3

[0184] By mixing shellac with the stearamide dispersion, the film formation and drying properties during the application of the coating onto the substrate paper were improved. Additionally, the binary coating layers exhibited an enhanced WVTR at a coating weight of 10 g/m.sup.2 compared to single-component layers. For WVTR, a minimum value was identified at a shellac-to-stearamide ratio of 1:1 (50:50) by varying the proportions of shellac and stearamide. Furthermore, mixing the stearamide dispersion with shellac allows for a reduction in the process-related polyvinyl alcohol (PVA) content.

TABLE-US-00004 TABLE 4 WVTR of Barrier Papers According to the Invention With a Binary Coating Composed of 50% Shellac and 50% Stearamide Dispersion as a Function of Coating Weight Coating weight in g/m.sup.2 WVTR.sub.Trop. (g/m.sup.2d) 1.3 139 16 2.9 97 3 6.8 92 1 9.4 67 2 12.9 55 5 15.8 42 1 20.3 36 1

[0185] The coating weight has a significant impact on the WVTR. When the coating weight was reduced below 7 g/m.sup.2, the WVTR increased from approximately 55 g/m.sup.2.d to over 90 g/m.sup.2.d. Conversely, increasing the coating weight made it possible to achieve WVTR values below 40 g/m.sup.2.d. In this case, the coating weight was approximately 20 g/m.sup.2.

Example 4Characterization of Ternary Coatings According to the Invention

4.1 Ternary System Composed of Candelilla Wax. Carnauba Wax, and Shellac

[0186] In this test series, ternary coatings composed of candelilla wax, carnauba wax, and shellac were examined for their water vapor barrier performance.

[0187] For this purpose, coatings with different proportions of candelilla wax, carnauba wax, and shellac, as well as PVA (6-9 mPas, 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol %), were prepared according to the description in Example 1. The ratios of the components in the formulations are provided in Table 3.

[0188] To produce coated papers, the coatings were applied to the base paper, as described in Example 1. The coating weight was 10 g/m.sup.2.

[0189] The drying time was approximately 1-2 minutes at a temperature of about 110 C.

[0190] The water vapor transmission rate (WVTR) was determined under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96). The results are presented in Table 5

TABLE-US-00005 TABLE 5 WVTR of Ternary Barrier Papers According to the Invention Composition of the coating (DC = 35%) WVTR.sub.Trop. (g/m2d) Note 50% shellac 16 1 grease-resistant 25% candelilla wax 25% carnauba wax 50% shellac 45 10 38.3% carnauba wax 11.7% candelilla wax

[0191] Barrier papers with temary layers composed of shellac, candelilla wax, and carnauba wax achieve very low WVTR values below 20 g/m.sup.2 d at a coating weight of 10 g/m.sup.2. Additionally, these ternary layers provide grease resistance, as determined by the palm kernel fat test (EN ISO 53116).

4.2 Ternary System Composed of Candelilla Wax, Stearic Acid, and Shellac

[0192] In this test series, ternary coatings composed of candelilla wax, stearic acid, and shellac were examined for their water vapor barrier performance.

[0193] For this purpose, coatings with different proportions of candelilla wax, stearic acid, and shellac were prepared according to the description in Example 1. The ratios of the components in the formulations are provided in Tables 4 and 5.

[0194] To produce coated papers, the coatings were applied to the base paper, as described in Example 1. The coating weight was consistently 10 g/m.sup.2. The drying time was approximately 1-2 minutes at a temperature of about 120 C.

[0195] The water vapor transmission rate (WVTR) was determined under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96). The results are presented in Tables 6 and 7.

TABLE-US-00006 TABLE 6 WVTR of Ternary Barrier Papers According to the Invention With High Concentration of Shellac Composition of the coating WVTR (g/m.sup.2d) 50% shellac 42 1 38.3% candelilla wax 11.7% stearic acid (DC = 32%) 50% shellac 29 12 25% candelilla wax 25% stearic acid (DC = 29%) 50% shellac 29 4 19.2% candelilla wax 30.8% stearic acid (DC = 28%) 50% shellac 46 8 17.8% candelilla wax 32.2% stearic acid (DC = 27%) 50% shellac 10 40 11.6% candelilla wax 38.4% stearic acid (DC = 26%)

TABLE-US-00007 TABLE 7 WVTR of ternary barrier papers according to the invention with high concentration of shellac Composition of the coating WVTR.sub.Trop. (g/m.sup.2d) Note 10% shellac 23 1 67.2% candelilla wax 22.8% stearic acid (DC = 38%) 10% shellac 22 2 45% candelilla wax 45% stearic acid (DC = 33%) 10% shellac 30 3 31.6% candelilla wax 58.4% stearic acid (DC = 31%) 10% shellac 19 4 overcoatability with 22.7% candelilla wax aqueous dispersions 67.3% stearic acid (DC = 29%) 10% shellac 43 9 overcoatability with 25% candelilla wax aqueous dispersions 65% stearic acid (DC = 30%)

[0196] Barrier papers with ternary layers composed of shellac, candelilla wax, and stearic acid achieve very low WVTR values below 20 g/m.sup.2.Math.d at a coating weight of 10 g/m.sup.2. Additionally, certain layer compositions, particularly those with a high proportion of shellac and/or stearic acid, result in good recoatability of the coating layer with water-based barriers, such as oxygen barriers or sealing media. Although shellac as a single component exhibits poor water vapor barrier properties with high WVTR values, the ternary system enabled WVTR values below 20 g/m.sup.2.Math.d, even with a 50% shellac content.

Example 5Characterization of Coatings According to the Invention with Film-Forming Agents

5.1 Variation of Film-Forming Agent Composition

[0197] In this test series, the influence of film-forming agents on the water vapor barrier performance of stearic acid coatings was investigated.

[0198] For this purpose, coatings were prepared with the base composition according to Table 8, following the description in Example 1.

TABLE-US-00008 TABLE 8 Base Composition Weigh-in (g) Composition (oven-dry %) 0.06 g MC 0.4% Methylcellulose (MC) 0.026 g HPMC 0.17% Hydroxypropylmethylcellulose (HPMC) 60 g SA = 88.2% stearic acid (25 wt. %) 89% stearic acid/11% PVA 10.9% PVA (dispersion with DC = 25) 0.05 g PEG400 0.33% PEG400

[0199] The MC and HPMC used differ as follows: [0200] HPMC1: Viscosity (2% aq.) 3 mPas: DS=1.9; MS=0.23 [0201] HPMC2: Viscosity (2% aq.) 50 mPas; DS=1.9; MS=0.23 [0202] HPMC3: Viscosity (2% aq.) 50 mPas; DS=1.8; MS=0.13 [0203] MC1: Viscosity (2% aq.) 4 mPas; DS=1.8 [0204] MC2: Viscosity (2% aq.) 25 mPas; DS=1.8 [0205] MC3: Viscosity (2% aq.) 400 mPas; DS=1.8

[0206] To produce coated papers, the coatings were applied to the base paper, as described in Example 1. The coating weight was 10 g/m.sup.2. The drying time was approximately 1-1.5 minutes at a temperature of about 110 C.

[0207] The water vapor transmission rate (WTR) was determined under tropical conditions (38 C., 90% RH) according to DIN 53122-1/DIN 53122 A (rel.: ISO 2528:1995, ASTM E 96).

TABLE-US-00009 TABLE 9 Influence of Film-Forming Agents on WVTR WVTR-values in g/m.sup.2d MC1 MC2 MC3 HPMC1 31 5 53 9 57 16 HPMC2 14 1 36 14 50 7 HPMC3 20 5 13 2 11 1

[0208] It was observed that the WVTR of the barrier papers decreases as the viscosity of the MC and HPMC used increases.

5.2 Variation of the Fatty Acid Component

[0209] The experiment corresponds to the one described in 5.1. However, instead of stearic acid, palmitic acid or mixtures of both fatty acids were used.

TABLE-US-00010 TABLE 10 Coating Compositions WVTR-values in g/m.sup.2d palmitic acid 33 23 50:50 palmitic 16 2 acid:stearic acid 33:66 palmitic 22 6 acid:stearic acid stearic acid 11 1

[0210] For further advantageous embodiments of the inventive device, reference is made to the general part of the description and the appended claims to avoid repetition.

[0211] Finally, it should be expressly pointed out that the embodiments of the inventive device described above serve merely to discuss the claimed teaching but do not limit the invention to these embodiments.