Bio-based composites as water vapor barrier layers on paper

Abstract

The present application relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly to 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; wherein the coated paper has a reduced permeability to at least one gas compared to the base paper. The invention also relates to a coating for producing the coated paper, a production method and a packaging produced thereby.

Description

Technical Field

[0001] The present invention relates to coated paper having high barrier properties to gases and moisture for use as packaging material. Background Art

[0002] Packaging accounts for a large proportion of global plastic waste pollution, so there is a push to find alternatives made from biodegradable materials.

[0003] Food packaging is particularly challenging as it requires good barrier properties to oxygen, water vapor and microorganisms. Food packaging materials are often composed of, for example, plastics such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE) and polypropylene (PP) because they have low weight and high mechanical stability in addition to good barrier properties.

[0004] Paper-based packaging materials have many advantages over plastic materials, such as recyclability, recyclability, and compostability. However, their applications are limited due to their generally poor barrier properties and high sensitivity to moisture.

[0005] To improve barrier properties, paper-based packaging materials can be laminated with aluminum or petroleum-based polymers such as PE, EVOH and PVC derivatives. However, these coatings complicate waste sorting and recycling and reduce compostability. Therefore, from an ecological point of view, it is highly desirable to use barrier layers based on natural bio-based polymers or to replace traditional metal- or plastic-based layers.

[0006] Examples of natural polymers tested for packaging applications include chitosan, hemicellulose, microfibrillated cellulose and starch. However, many natural polymers are hydrophilic and films made from these materials are often hygroscopic, causing them to partially lose their barrier properties at high air humidity.

[0007] JP 2006 096981A describes a coating liquid for a substrate (e.g. a film, sheet, paper, fabric or nonwoven) which imparts moisture resistance to the substrate. The main components of the coating liquid are shellac and paraffin. In order to achieve the desired moisture resistance, the coating layer must be subjected to a heat treatment at a temperature of at least 90°C for at least 5 seconds. The water vapor transmission rate should be less than 50 g / (m 2 d) However, paper coated in this way is poorly biodegradable.

[0008] WO 2020 / 152292A1 describes a barrier paper for food packaging. The barrier paper consists of a paper substrate with a pulp fiber mass proportion greater than or equal to 90% and a barrier layer arranged on the front and / or back of the paper substrate. The barrier layer contains a polymer stabilizer, such as polyvinyl alcohol or starch, and at least one wax, such as beeswax and / or at least one vegetable oil, such as olive oil, soybean oil or rapeseed oil. With the barrier paper, it is believed that the water vapor permeability is less than or equal to 150 g / (m2d) according to DIN 53122-1. However, such a value has not been confirmed.

[0009] WO 2020 / 011824 A1 describes a packaging system comprising a first paper layer with granular activated carbon, a first barrier layer composed of a binder and a pigment arranged on the paper layer, and a second barrier layer comprising an acrylate copolymer and a wax arranged on the first barrier layer. With the barrier paper, it is believed that the water vapor transmission rate is less than or equal to 125 g / (m 2 d). However, such a value has not been confirmed here either.

[0010] US 9,902815 B2 and the scientific publication Hult et al., 2013 by the same authors describe a process for esterifying lignin with fatty acids, in particular with a mixture of tall oil fatty acids. The main components of this mixture are unsaturated fatty acids, such as oleic acid, linoleic acid and linolenic acid, which react with lignin to varying degrees of esterification.

[0011] DE 10 2017 108 577 A1 relates to a coating comprising at least one polymer and at least one crystallizable material and a method for producing the same. At the melting temperature of the crystallizable material, the viscosity of the polymer is believed to be no more than 10 12 mPas. This results in superhydrophobic and regenerable layers. However, these layers have very low gas barrier properties. Summary of the invention

[0012] The invention is based in particular on the surprising discovery that the combination of at least one natural wax or carboxylic acid component on the one hand and at least one natural resin on the other hand produces a coating with a high barrier effect against gases and moisture, which coating is biodegradable. The coated paper according to the invention produced with this coating has a sufficient barrier effect for use in the food industry and is biodegradable and recyclable. The coating of the invention can be a binary composition or a ternary composition of a natural resin, a natural wax and a carboxylic acid component. The ternary composition can not only achieve a higher barrier effect in particular, but can also provide the coated paper with additional properties, such as an improved oil resistance.

[0013] Thus, according to a first aspect, the present invention relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly to the base paper, wherein the coating layer comprises:

[0014] a) at least one natural wax and / or at least one carboxylic acid component, and

[0015] b) at least one natural resin;

[0016] Wherein, compared with the base paper, the coated paper has a reduced permeability to at least one gas.

[0017] Surprisingly, similar properties of the barrier effect against gases and moisture can also be achieved for coated papers that do not contain natural resins if a natural wax or carboxylic acid component is applied as a coating to the base paper together with at least one film former, in particular a cellulose derivative. Thus, according to a second aspect, the present invention relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly to the base paper,

[0018] wherein the coating comprises:

[0019] a) at least one natural wax and / or at least one carboxylic acid component, and

[0020] b) at least one film former, in particular a cellulose derivative;

[0021] Therein, the coated paper has a reduced permeability to at least one gas compared to the base paper.

[0022] The barrier effect and biodegradability of the present invention are achieved by a two-component or three-component coating having the above components and a suitable solvent.

[0023] Therefore, according to a third aspect, the present invention relates to a coating for coating paper, comprising the components defined according to the first or second aspect and a solvent selected from water, tetrahydrofuran (THF), ethanol, methanol and ethyl acetate, preferably the solvent is water.

[0024] The substantial barrier effect of the coating in the coated paper is achieved in particular by the method according to the invention for producing coated paper. Thus, according to a fourth aspect, the invention relates to a method for producing coated paper having a base paper and a coating, comprising the following steps:

[0025] a) preparing the coating by mixing the components;

[0026] b) Provide base paper;

[0027] c) applying the coating to base paper, preferably using curtain coating or knife coating; and

[0028] d) curing the coating to form the coating.

[0029] According to a fifth aspect, the present invention relates to a package comprising a coated paper according to the first aspect or the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a graph of the measurement results of the water vapor transmission rate (WVTR) measurement of a dual coating according to the invention of Example 3.1, prepared from candelilla wax and shellac, with a constant applied weight and a varying ratio of shellac to candelilla wax.

[0031] Figure 2 Shown is a graph of the measurement results of a WVTR measurement of a dual coating according to the invention of Example 3.1, which was prepared from candelilla wax and shellac with a constant shellac to candelilla wax ratio and varying application weight.

[0032] Figure 3 Shown is a graph of the results of the WVTR measurement over storage time in Example 3. Paper having a coating consisting of 80% candelilla wax dispersion and 20% shellac was tested after 10, 50, 100, 150, 200 and 250 days of storage. DETAILED DESCRIPTION

[0033] definition

[0034] In the context of the present invention and according to the general understanding in the field of papermaking technology, the term "coating" refers to a coating comprising or consisting of a binder, an additive and optionally a pigment or a matrix pigment, which is applied ("coated") to the surface of paper with the aid of a special coating device to treat or modify the surface of the base paper. Paper made in this way is called "coated paper".

[0035] In the context of the present invention, "coated paper" is understood to mean a base paper comprising one or more layers (ie coatings) applied by coating. The layers as substrate of such coated paper include functional layers and structure-forming layers (eg compensation layers for smoothing the surface).

[0036] According to the invention, the term "coating" is used as a general term for all spreadable coating compositions, preparations and / or solutions used in the paper industry to treat, modify or finish the surface of paper. The term "coating" refers to a coating that is applied and hardened on the base paper.

[0037] "Paper" is a flat material consisting essentially of fibers of plant origin, which is produced by dewatering a fiber suspension on a screen. The resulting fiber web is compacted and dried. Within the scope of the present invention, the flat materials "cardboard" and "plywood" produced in the same way are also covered by paper. A distinction is made between paper, cardboard and plywood only on the basis of the weight per unit area, with plywood having a weight per square meter of more than 600 g / m2. 2 , the square meter weight of the cardboard is greater than 150g / m 2 And less than or equal to 600g / m 2 The square meter weight of the paper is less than or equal to 150g / m 2 .

[0038] "Water Vapor Transmission Rate", in English "Water Vapor Transmission Rate" and abbreviated "WVTR" is a measurement of the permeability of water vapor through a material. To determine the WVTR value, it is necessary to measure the amount of water that evaporates through an area of ​​one square meter in 24 hours. The WVTR is expressed in grams of water evaporated per square meter per day. Unless otherwise stated, according to the present invention, the WVTR is determined under tropical conditions (38°C, 90% RH) according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96). The term "water vapor transmission rate" is used synonymously with WVTR.

[0039] According to the invention, surfaces having a contact angle with respect to water of 145° or more, preferably 150° or more, are referred to as "superhydrophobic". At such high contact angles, typically only about 2% to 3% of the surface of a water droplet is in contact with the superhydrophobic surface; its wettability is therefore extremely low. In addition, superhydrophobic surfaces are characterized by a sliding angle of less than 10°.

[0040] According to the invention, the "contact angle" of a drop on a surface is understood to mean the angle that the tangent line between the drop base and the surface forms with the horizontal plane. It is measured in degrees and depends on various factors, such as the surface tension of the liquid and the properties of the surface.

[0041] According to the invention, "sliding angle" is understood to mean the angle of inclination of a surface when a droplet rolls off the surface. It is usually used to characterize superhydrophobic surfaces with very high contact angles, where the droplet is approximately spherical. At smaller contact angles, the droplet can also move from the surface, but usually first deforms and then slides on the surface. At a sliding angle of 180°, the droplet does not roll off, but sticks to the coating, even if it hangs downward.

[0042] Coated paper and coatings

[0043] According to a first aspect, the present invention relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly to the base paper, wherein the coating layer comprises:

[0044] a) at least one natural wax and / or at least one carboxylic acid component, and

[0045] b) at least one natural resin;

[0046] Wherein, compared with the base paper, the coated paper has a reduced permeability to at least one gas.

[0047] According to one embodiment of the coated paper, the permeability of the coated paper to at least one gas is lower than the permeability of a coated paper having the same base paper and having a coating layer made of a natural resin and a coating layer made of a natural wax and / or fatty acid component, at the same total applied amount. Due to this effect of the coating of the invention, it is also called a "barrier layer".

[0048] The coating reduces the permeability of the coated paper to at least one gas compared to the base paper. These gases may be oxygen (O2), nitrogen (N2), carbon dioxide (CO2), methane (CH4), hydrogen (H2), water vapor or mixtures thereof, such as air. In particular, the water vapor transmission rate (WVTR) is reduced.

[0049] It is hypothesized that by combining with at least one natural resin, the crystallization of the natural wax and carboxylic acid components on the surface can be limited. This can improve the water vapor barrier because, although the crystal structure creates superhydrophobic properties by forming structures on the surface, it does not form a uniform, closed coating, which is necessary to prevent the penetration of water vapor molecules.

[0050] The surface of the coating is also not super-hydrophobic. The coating has a contact angle of no more than 150° relative to water. The contact angle can be, for example, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140° or 145°. Even above 145°, the surface is still considered to be super-hydrophobic. Therefore, the contact angle is preferably no more than 145°. According to one embodiment, the contact angle is no more than 130°. According to one embodiment, the contact angle is no more than 115°.

[0051] In addition, it is preferred that the coating has a rolling angle of greater than 10° relative to a 4 μL volume of water droplet. The rolling angle can be, for example, 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°, 180°. According to one embodiment, the rolling angle is greater than 20°. According to one embodiment, the rolling angle is greater than 40°. According to one embodiment, the rolling angle is greater than 60°.

[0052] By using the above bio-based raw materials, a reduction in plastic pollution in the environment is achieved by utilizing raw materials with improved recyclability and biodegradability. In addition, as shown in the examples, the use of natural resins can reduce the amount of stabilizers that are usually not easily biodegradable.

[0053] With the coating according to the invention, coated paper with high barrier properties, in particular very low WVTR, can be achieved. According to one embodiment, the coating has a unit weight of 10±1 g·m -2 When WVTR is less than 50g·m -2 ·d -1 .

[0054] The WVTR of the coated paper according to the invention may be, for example, 50 g m -2 ·d -1 48g·m -2 ·d -1 46g·m -2 ·d -1 44g·m -2 ·d -1 42g·m -2 ·d -1 , 40g·m -2 ·d -1 38g m 2 d -1 、36g·m -2 ·d -1 、34g·m -2 ·d -1 、32g·m -2 ·d -1 、30g·m -2 ·d -1 , 28g·m -2 ·d -1 , 26g m 2 d -1 , 24g·m-2 ·d -1 , 22g·m -2 ·d -1 , 20g·m -2 ·d -1 , 18g·m -2 ·d -1 , 16g·m -2 ·d -1 14g m -2 d -1 , 12g·m -2 ·d -1 , 10g·m -2 ·d -1 , 8g·m -2 ·d -1 , 6g·m -2 ·d -1 , 4g·m -2 ·d -1 , 2g·m -2 ·d -1 , 1g·m -2 ·d -1 By selecting appropriate coating ingredients and adjusting the crystallinity, WVTR can be achieved to be no greater than 20g·m -2 ·d -1 , even less than 10 g·m -2 ·d -1 .

[0055] The natural resin is preferably an organic, chemically / thermally crosslinked matrix. According to one embodiment, the natural resin is selected from the group consisting of shellac, rosin, balsam, shellac, rosin, sandarac, frankincense, conifer resin, dammar, gum arabic and elemi. Preferably, the natural resin is shellac.

[0056] Shellac is a resinous substance obtained from the secretions of lac insects (aphids, Aphididae) after feeding on certain plants. Most of it (65-75%) is composed of free and esterified aliphatic and aromatic polyhydroxy acids. The main component is elaeolic acid (up to 32%) and lac acid If only these main components are considered, it is calculated that three or four molecules are linked together in each case (trimers and tetramers). Since the monomers contain several hydroxyl and carboxyl groups, three-dimensional networks can be formed - this is common in thermosetting plastics. Other components are colorants (4-8%), bitter substances and some waxes (shellac wax; reddish-brown, brittle, very hard, wood wax esters, wax acid esters and wax alcohols). Shellac is biodegradable.

[0057] Strictly speaking, rosin is more of a volatile oil. It is obtained by distilling the resins of coniferous trees, mainly pine trees. Rosin consists mainly of terpenes such as α-pinene, β-pinene. It can be used as a solvent and in the production of paints and varnishes. Balsam is an aromatic resin, which is often mixed with essential oils. It is obtained directly from the trunk or branches of the tree, either by incision or by natural secretions. The chemical composition is variable, but usually contains essential oils and resin acids. Balsam is used in particular in perfumery, medicine and cosmetics. Shellac is a resin obtained by cutting the bark of various sumac trees. It is used in the production of varnishes and paints and in the printing industry and consists of complex ester and polyphenolic compounds.

[0058] Rosin is a resin that is a by-product of rosin production, especially distillation of rosin from coniferous resins. It consists mainly of resin acids (e.g. abietic acid) and is used in the electronics industry for soldering, in the music industry for stringed instruments, and in chemistry as an adhesive or binder. Sandar is a resin obtained from various cypress trees, especially by cutting the bark. It is used in the production of varnishes and as incense. Sandar chemically consists mainly of terpenoids. Frankincense is a resin obtained from the Boswellia tree (Pistacia lentiscus), especially by cutting. Frankincense chemically consists of a mixture of resin acids, essential oils and resin alcohols. It is used as a natural additive in the food industry and in cosmetics.

[0059] Conifer resin is a general term for resins produced by coniferous trees such as pine, spruce and fir. It contains terpenes, resin acids and sometimes essential oils. Conifer resins are used in the production of rosin, varnishes and as adhesives. Dammar is a resin obtained from various tropical tree species, especially by cutting the bark. Dammar chemically consists of a mixture of terpenes and resin acids. It is used in paints and as an adhesive.

[0060] Gum arabic is a resin obtained from various acacia trees, especially by cutting the bark. It is chemically a complex polysaccharide, which may also contain proteins. It is used as a thickener in the food industry and as an adhesive in the printing industry. Elemi is a resin extracted from tropical trees of the genus Olive. It chemically consists of a mixture of terpenes, resin acids and essential oils. Elemi is used in the perfume and cosmetics industry.

[0061] Although these resins have different chemical compositions, they have the same physical and chemical properties as shellac and can be used as adhesives, binders, or coatings like shellac.

[0062] Carboxylic acid components that can be used according to the invention are, for example, fatty acids, fatty acid amides, fatty acid esters, fatty acid salts, hydroxy fatty acids, hydroxy fatty acid amides, hydroxy fatty acid esters, hydroxy fatty acid salts, or dicarboxylic acids, and their dicarboxylic acid esters, dicarboxylic acid amides or dicarboxylic acid salts. Examples of dicarboxylic acids that can be used according to the invention are tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid or docosanedioic acid.

[0063] The carboxylic acid component can be a saturated or unsaturated fatty acid with 12 to 40 carbon atoms. Examples of saturated fatty acids are lauric acid, myristic acid, palmitic acid, heptadecanoic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, lacquer wax acid, tetratricoic acid. Examples of unsaturated fatty acids include myristoleic acid, palmitoleic acid, heptadecenoic acid, petroselinic acid, oleic acid (OA), elaidic acid, vaccenic acid, gadoleic acid, gondoic acid, cetyl oleic acid, erucic acid and nervonic acid. Examples of unsaturated fatty acids include linoleic acid (LA), α-linolenic acid (ALA), γ-linolenic acid (GLA), calendula acid, punicic acid, α-eleostearic acid, β-eleostearic acid, octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid (arachidonic acid, EPA), docosadienoic acid, docosatetraenoic acid ( ADA), docosapentaenoic acid, (Clupa(no) ), (DPA-3) Docosahexaenoic acid ( DHA) and tetracosahexanoic acid (nisinic acid).

[0064] 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 bonds. According to one embodiment, the fatty acid is selected from margaric acid, stearic acid, palmitic acid, linoleic acid, α-linolenic acid, γ-linolenic acid. According to one embodiment, the carboxylic acid component is stearic acid or its amide or salt.

[0065] The fatty acid salts of the present invention are complexes of chromium (III) chloride and fatty acids, as well as aluminum salts, calcium salts, sodium salts, potassium salts and ammonium salts. Preferred fatty acid salts are monovalent salts of sodium, potassium or ammonium ions.

[0066] According to one embodiment, it 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. Other examples of fatty acid mixtures are 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 linolenic acid, a mixture of stearic acid, palmitic acid and linolenic acid, a mixture of stearic acid, oleic acid and linolenic acid, a mixture of stearic acid, oleic acid and linolenic acid, a mixture of stearic acid, linoleic acid and linolenic acid. Preferred mixture is a mixture of stearic acid and palmitic acid.

[0067] According to the invention, waxes that can be used include, among others, carnauba wax, candelilla wax, beeswax, Chinese wax and Japan wax. Preferred waxes are carnauba wax or candelilla wax.

[0068] According to one embodiment, the polymer stabilizer is a cross-linked or non-cross-linked stabilizer. The polymer stabilizer prevents the finely distributed coating components from agglomerating. When used in large amounts, the stabilizer can also act as a binder. The polymer stabilizer can be selected from the following group: polyvinyl alcohol, starch, carboxyl-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, α-isodecyl-ω-hydroxy-poly(oxy-1,2-ethylenediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, carboxyl-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, α-isodecyl-ω-hydroxy-poly(oxy-1,2-ethylenediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer and mixtures thereof and mixtures thereof. According to one embodiment, the polymer stabilizer is polyvinyl alcohol. Polyvinyl alcohol is available on the market with different degrees of hydrolysis and viscosities. Preference is given to using polyvinyl alcohols having a viscosity of 2-10 mPas (determined as a 4% aqueous solution at 20° C. in accordance with DIN 53015 / JIS K 6) and a degree of hydrolysis of >80 mol %. Commercially available examples include KURARAY 6-88 and KURARAY 6-98.

[0069] According to one embodiment, the coating comprises a carboxylic acid component, a natural resin and an optional polymer stabilizer. In the composition, the ratio of the carboxylic acid component relative to the total mass of the coating can be 15 to 85% by weight. For example, the ratio of the carboxylic acid component can be 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight or 85% by weight. According to one embodiment, the ratio of the carboxylic acid component is in the range of 25 to 75% by weight. According to one embodiment, the ratio of the carboxylic acid component is in the range of 30 to 75% by weight. According to one embodiment, the ratio of the carboxylic acid component is in the range of 40 to 65% by weight.

[0070] In the binary composition of the coating composed of the carboxylic acid component, the natural resin and the optional polymer stabilizer, the proportion of the natural resin relative to the total mass of the coating can be in the range of 10 to 70% by weight. For example, the proportion of the natural resin can be 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight or 70% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 20 to 60% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 25 to 55% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 30 to 50% by weight.

[0071] In the composition of the coating composed of the carboxylic acid component, the natural resin and the polymer stabilizer, the proportion of the polymer stabilizer relative to the total mass of the coating can be less than 30% by weight. For example, the proportion of the polymer stabilizer can be 0.1% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2.0% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 26% by weight or 28% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 1 to 15% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 2 to 10% by weight.

[0072] According to one embodiment, the binary coating comprises natural wax, natural resin and optional polymer stabilizer. In the composition, the ratio of natural wax relative to the total mass of the coating can be in the range of 15 to 95% weight percent. For example, the ratio of the carboxylic acid component can be 15% weight percent, 20% weight percent, 25% weight percent, 30% weight percent, 35% weight percent, 40% weight percent, 45% weight percent, 50% weight percent, 55% weight percent, 60% weight percent, 65% weight percent, 70% weight percent, 75% weight percent, 80% weight percent, 85% weight percent, 90% weight percent or 95% weight percent. According to one embodiment, the ratio of natural wax is in the range of 30 to 95% weight percent. According to one embodiment, the ratio of natural wax is in the range of 40 to 90% weight percent. According to one embodiment, the ratio of natural wax is in the range of 50 to 85% weight percent. According to one embodiment, the ratio of natural wax is in the range of 60 to 80% weight percent.

[0073] In the composition of the coating of natural wax, natural resin and optional polymer stabilizer, the proportion of natural resin relative to the total mass of the coating can be in the range of 5 to 70% by weight. For example, the proportion of natural resin can be 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight or 70% by weight. According to one embodiment, the proportion of natural resin relative to the total mass of the coating is in the range of 5 to 60% by weight. According to one embodiment, the proportion of natural resin relative to the total mass of the coating is in the range of 10 to 40% by weight. According to one embodiment, the proportion of natural resin relative to the total mass of the coating is in the range of 20 to 40% by weight.

[0074] In the composition of the coating composed of natural wax, natural resin and polymer stabilizer, the proportion of polymer stabilizer relative to the total mass of the coating can be less than 30% by weight. For example, the proportion of polymer stabilizer can be 0.1% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2.0% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 26% by weight or 28% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 1 to 15% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 2 to 10% by weight.

[0075] According to one embodiment, the coating comprises at least one film former. The film former 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), hydroxyethylmethylcellulose (HEMC). According to one embodiment, the coating comprises one, two, three, four, five, six, seven, eight, nine or ten film formers. According to one embodiment, the coating comprises the film formers methylcellulose and carboxymethylcellulose.

[0076] According to one embodiment, the proportion of the film former relative to the total mass of the coating is in the range of 0.2 to 5.0 weight percent. For example, the proportion of the film former can be: 0.2 weight percent, 0.4 weight percent, 0.6 weight percent, 0.8 weight percent, 1.0 weight percent, 1.2 weight percent, 1.4 weight percent, 1.6 weight percent, 1.8 weight percent, 2.0 weight percent, 2.4 weight percent, 2.8 weight percent, 3.0 weight percent, 3.4 weight percent, 3.8 weight percent, 4.0 weight percent, 4.4 weight percent, 4.8 weight percent, 5.0 weight percent. According to one embodiment, the proportion of the film former relative to the total mass of the coating is in the range of 0.3 to 2.0 weight percent. According to one embodiment, the proportion of the film former relative to the total mass of the coating is in the range of 0.3 to 1.0 weight percent.

[0077] Even without natural resins, the coated paper according to the invention can achieve surprisingly comparable performance for gas and moisture barrier effects. Therefore, according to a second aspect, the present invention relates to a coated paper comprising a base paper and at least one coating layer applied directly or indirectly to the base paper,

[0078] wherein the coating comprises:

[0079] a) at least one natural wax and / or at least one carboxylic acid component, and

[0080] b) at least one film former, in particular a cellulose derivative;

[0081] Wherein, compared with the base paper, the coated paper has a reduced permeability to at least one gas.

[0082] Thus, a film former is used instead of a natural resin. Apart from this, the coating of the coated paper according to the second aspect has the same features as the coating of the coated paper according to the first aspect, unless otherwise defined.

[0083] According to one embodiment, the coating comprises a carboxylic acid component, at least two film formers, in particular cellulose derivatives, and at least one polymer stabilizer.

[0084] In the composition, the proportion of the carboxylic acid component relative to the total mass of the coating can be in the range of 75 to 98% by weight, for example, the proportion of the carboxylic acid component can be 75% by weight, 76% by weight, 77% by weight, 78% by weight, 79% by weight, 80% by weight, 81% by weight, 83% by weight, 84% by weight, 85% by weight, 86% by weight, 87% by weight, 88% by weight, 89% by weight, 90% by weight, 91% by weight, 93% by weight, 94% by weight, 95% by weight, 96% by weight, 97% by weight or 98% by weight. According to one embodiment, the proportion of the carboxylic acid component is in the range of 85 to 92% by weight. According to one embodiment, the proportion of the carboxylic acid component is in the range of 87 to 90% by weight. According to one embodiment, the proportion of the carboxylic acid component is in the range of 40 to 65% by weight.

[0085] In the composition of the coating composed of the carboxylic acid component, the two film formers and the optional polymer stabilizer, the proportion of the film former relative to the total mass of the coating can be in the range of 0.2 to 5.0 weight percent. For example, the proportion of the film former can be 0.2 weight percent, 0.4 weight percent, 0.6 weight percent, 0.8 weight percent, 1.0 weight percent, 1.2 weight percent, 1.4 weight percent, 1.6 weight percent, 1.8 weight percent, 2.0 weight percent, 2.4 weight percent, 2.8 weight percent, 3.0 weight percent, 3.4 weight percent, 3.8 weight percent, 4.0 weight percent, 4.4 weight percent, 4.8 weight percent, 5.0 weight percent. According to one embodiment, the proportion of the film former relative to the total mass of the coating is in the range of 0.3 to 2.0 weight percent. According to one embodiment, the proportion of the film former relative to the total mass of the coating is in the range of 0.3 to 1.0 weight percent.

[0086] In the composition of the coating composed of the carboxylic acid component, the natural resin and the polymer stabilizer, the proportion of the polymer stabilizer relative to the total mass of the coating can be less than 30% by weight. For example, the proportion of the polymer stabilizer can be 0.1% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2.0% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 26% by weight or 28% by weight. It is advantageous to have a slightly higher proportion of the polymer stabilizer compared to the natural resin barrier layer. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is 5-15% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is 7-13% by weight.

[0087] According to an embodiment of the coated paper of the first aspect, it is a ternary coating, i.e. a coating comprising at least two natural waxes or at least one natural wax and a saturated fatty acid and at least one natural resin. In the ternary system of the present invention, the proportion of polymer stabilizers can be further reduced. In addition, a layer that can be directly applied can also be generated. By changing the composition of the coating, the same barrier properties (WVTR) can be maintained depending on the availability of the various components. Finally, the ternary coating also has oil-proof properties.

[0088] According to an embodiment of the coated paper of the first aspect, the coating comprises two kinds of natural waxes, natural resins and optional polymer stabilizers. In the composition, the ratio of natural wax relative to the total mass of the coating can be in the range of 10 to 80% weight percent. For example, the ratio of the carboxylic acid component can be 10% weight percent, 15% weight percent, 20% weight percent, 25% weight percent, 30% weight percent, 35% weight percent, 40% weight percent, 45% weight percent, 50% weight percent, 55% weight percent, 60% weight percent, 65% weight percent, 70% weight percent, 75% weight percent or 80% weight percent. According to one embodiment, the ratio of natural wax is in the range of 15 to 60% weight percent. According to one embodiment, the ratio of natural wax is in the range of 25 to 55% weight percent. According to one embodiment, the ratio of natural wax is in the range of 35 to 55% weight percent. According to one embodiment, the ratio of natural wax is in the range of 40 to 50% weight percent.

[0089] In the composition of the coating composed of two natural waxes, a natural resin and an optional polymer stabilizer, the proportion of the natural resin relative to the total mass of the coating can be in the range of 20 to 90% by weight. For example, the proportion of the natural resin can be 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight or 90% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 30 to 85% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 40 to 70% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 45 to 60% by weight.

[0090] In the composition of the coating composed of two natural waxes, a natural resin and a polymer stabilizer, the proportion of the polymer stabilizer relative to the total mass of the coating can be less than 30% by weight. For example, the proportion of the polymer stabilizer can be 0.1% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2.0% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 26% by weight or 28% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 1 to 15% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 2 to 10% by weight.

[0091] According to one embodiment, the ternary coating comprises a carboxylic acid component, a natural wax, a natural resin and an optional polymer stabilizer. In the composition, the carboxylic acid component can preferably be in the range of 5 to 85% weight percentage relative to the ratio of the total mass of the coating. For example, the ratio of the carboxylic acid component can be 5% weight percentage, 10% weight percentage, 15% weight percentage, 20% weight percentage, 25% weight percentage, 30% weight percentage, 35% weight percentage, 40% weight percentage, 45% weight percentage, 50% weight percentage, 55% weight percentage, 60% weight percentage, 65% weight percentage, 70% weight percentage, 75% weight percentage, 80% weight percentage or 85% weight percentage. According to one embodiment, the ratio of the carboxylic acid component is in the range of 55 to 75% weight percentage. According to one embodiment, the ratio of the carboxylic acid component is in the range of 15 to 70% weight percentage. According to one embodiment, the ratio of the carboxylic acid component is in the range of 25 to 65% weight percentage. According to one embodiment, the ratio of the carboxylic acid component is in the range of 30 to 40% weight percentage.

[0092] In the composition, the ratio of natural wax to the total mass of the coating can be in the range of 15 to 95% by weight. For example, the ratio of the carboxylic acid component can be 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight or 95% by weight. According to one embodiment, the ratio of natural wax is 30 to 95% by weight. According to one embodiment, the ratio of natural wax is in the range of 40 to 90% by weight. According to one embodiment, the ratio of natural wax is in the range of 50 to 85% by weight. According to one embodiment, the ratio of natural wax is in the range of 60 to 80% by weight.

[0093] In the composition of the coating composed of a carboxylic acid component, a natural wax, a natural resin and an optional polymer stabilizer, the proportion of the natural resin relative to the total mass of the coating can be in the range of 5 to 70% by weight. For example, the proportion of the natural resin can be 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight or 70% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 20 to 60% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 25 to 55% by weight. According to one embodiment, the proportion of the natural resin relative to the total mass of the coating is in the range of 30 to 50% by weight.

[0094] In the composition of the coating composed of the carboxylic acid component, the natural wax, the natural resin and the polymer stabilizer, the proportion of the polymer stabilizer relative to the total mass of the coating can be less than 30% by weight. For example, the proportion of the polymer stabilizer can be 0.1% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2.0% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 26% by weight or 28% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 1 to 15% by weight. According to one embodiment, the proportion of the polymer stabilizer relative to the total mass of the coating is in the range of 2 to 10% by weight.

[0095] The coating weight per unit area of ​​coated paper can be between 2 and 30 g·m -2 For example, the weight per unit area can be 2 g·m -2 , 4g·m -2 , 5g·m -2 , 6g·m -2 , 8g·m -2 , 10g·m -2 , 12g·m -2 , 14g·m -2 , 15g·m -2 , 16g·m -2 , 18g·m -2 , 20g·m -2 , 22g·m -2 , 24g·m -2 , 25g·m -2 , 26g·m -2 , 28g·m -2 or 30 g·m -2 According to one embodiment, the coating has a unit area weight of 2 to 30 g·m -2 According to one embodiment, the coating has a unit area weight of 5 to 20 g·m -2 According to one embodiment, the coating has a unit area weight of 8 to 15 g·m -2 within the range.

[0096] According to the first aspect or the second aspect, the coated paper is biodegradable due to the materials present in these coatings. "Biodegradability" refers to the ability of an organic chemical to be biodegraded, i.e., to be decomposed by a living organism or its enzymes. Ideally, this chemical metabolism would proceed completely until mineralization, but it may also be stopped by degradation of stable transformation products. The OECD's chemical testing guidelines are also widely used for chemical approval. The OECD test series 301 (AF) test demonstrates rapid and complete biodegradation (rapid biodegradability) under aerobic conditions. There are different test methods for well-soluble or poorly soluble and volatile substances. In the sense of the present invention, "biodegradable" or "biodegradable" refers to paper having the following characteristics: having a biodegradability of at least 40% measured according to OECD 301F or a biodegradability of at least 20% measured according to OECD 302C (MITI-II-test), and therefore having inherent or basic degradability. This corresponds to the limit value for OECD 302C according to "Revised Introduction to the OECD Guidelines for testing of Chemicals, Section 3, Part 1, 23 March 2006". From a limit value of at least 60% measured according to OECD 301F, paper is also referred to as readily biodegradable.

[0097] According to an embodiment of the coated paper of the first or second aspect, the coated paper has ready biodegradability according to OECD 301.

[0098] Furthermore, according to the first aspect or the second aspect, the coated paper can be recycled. Paper recycling refers to the dissolution and reprocessing of waste paper, waste board and cardboard in paper mill equipment to produce new paper, cardboard and cardboard therefrom. To a lesser extent, the recycled waste paper is initially used to produce waste paper pulp as semi-paper stock and only subsequently for the production of new paper. Printing ink removal or deinking (from the English ink = "printing ink", "ink") is a key process in paper recycling to remove printing ink from printed waste paper. The assessment of recyclability can be carried out, for example, using the INGEDE method 11. Using the INGEDE method 11, the coated paper according to the present invention achieves a deinkability score of more than 50. The deinkability score is preferably more than 70.

[0099] With the composition of the barrier layer used according to the first aspect or the second aspect, the coated paper can be used for direct or indirect food contact. In particular, it is suitable for approval according to the guidelines of the European Food Safety Authority.

[0100] In principle, all types of paper can be used as base paper for the coated paper according to the first or second aspect, i.e. paperboard, thick paper or plain paper. Paper made of hardwood and softwood pulp is preferably used. Papers with low basis weight are generally suitable for food packaging, since they are flexible and save material. In particular for such papers, the coating according to the invention leads to a significant improvement in the barrier properties.

[0101] According to one embodiment of the coated paper of the first aspect or the second aspect, the weight per unit area of ​​the base paper is less than 150 g. · m -2 The weight per unit area can be, for example, 150 g · m -2 , 145g · m -2 , 140g · m -2 , 135g · m -2 , 130g · m -2 , 125g · m -2 , 120g · m -2 , 115g · m -2 , 110g · m -2 , 105g · m -2 , 100g · m -2 , 95g · m -2 , 90g · m -2 , 85g · m -2 , 80g · m -2 , 75g · m -2 , 70g · m -2 、65g · m -2 、60g · m -2 , 55g · m -2 , 50g · m -2 , 45g · m -2 , 40g · m -2 , 35g · m -2 or 30g · m-2 According to one embodiment, the weight per unit area is less than 100 g · m -2 According to one embodiment, the weight per unit area is less than 80 g · m -2 According to one embodiment, the weight per unit area is 50 to 80 g · m -2 .

[0102] The coated paper according to the first aspect or the second aspect may comprise further layers in addition to the barrier layer. According to one embodiment, the coated paper comprises further layers selected from the group consisting of coatings, inks, sealing media and adhesives.

[0103] The other layer may be disposed on the barrier layer, between the base paper and the barrier layer, or on the side of the base paper opposite to the semi-crystalline coating.

[0104] Thus, the barrier layer can be applied directly to the base paper. In this case, the barrier layer is in direct contact with the base paper. Indirect application means that there is one or more layers between the coating and the base paper.

[0105] The further layers can in particular further reduce the permeability of the coated paper relative to the base paper to at least one gas, or form a barrier to liquids or viscous substances (eg fats, oils, hydrocarbons).

[0106] Other layers may, inter alia:

[0107] a) comprises at least one hydrophobic polymer, for example based on polyacrylates, styrene / butadiene copolymers and / or polyolefins

[0108] b) comprises at least one hydrophilic polymer, for example a hydrophilic polymer based on polyvinyl alcohol

[0109] c) comprises at least one inorganic pigment, for example a platelet-shaped pigment, for example a layered silicate such as kaolin,

[0110] d) comprises at least one inorganic pigment and a binder,

[0111] e) contains amorphous regions and crystalline regions,

[0112] f) contains or consists of a substance selected from the group consisting 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,

[0113] g) reducing or preventing the transfer of substances, in particular hydrophobic substances, such as substances according to point e) above, for example preventing or reducing the transfer of substances from the underlying layer to the food, in particular fat-containing food,

[0114] h) comprises or consists of at least one metal (for example aluminum, gold) and / or metal oxide (for example aluminum oxide), in particular a metallization layer,

[0115] i) at least heat-sealable or cold-sealable,

[0116] j) at least comprising a binder thereof,

[0117] k) comprises or consists of at least one thermoplastic material, in particular as a heat-sealable material.

[0118] The base paper of the coated paper according to the first aspect or the second aspect may be a single-sided or double-sided coated base paper or an uncoated base paper.

[0119] For coated base paper, the surface is coated with a coating containing an adhesive. As a material for applying the adhesive, a coating is used, the main component of which can be starch, starch derivatives, chalk, kaolin, casein or plastic dispersion. This gives the base paper a more sealed, smoother and more stable surface.

[0120] Uncoated base papers can also be surface treated and contain up to 5 g / m 2 of pigment.

[0121] In order to be used as packaging in the food sector, paper requires a certain tear strength or breaking strength. According to one embodiment, the width-dependent breaking force of the coated paper in the fiber direction is between 3.0 and 6.0 kN·m -1 The width-dependent breaking force in the fiber direction can be, for example, 3.0 kN·m -1 、3.2kN·m -1 、3.4kN·m -1 、3.5kN·m -1 、3.6kN·m -1 、3.8kN·m -1 , 4.0kN·m -1 , 4.2kN·m -1 , 4.4kN·m -1 , 4.5kN·m -1 , 4.6kN·m -1 , 4.8kN·m -1 、5.0kN·m -1 , 5.2kN·m -1 、5.4kN·m -1 , 5.5kN·m -1 、5.6kN·m -1 、5.8kN·m -1 、6.0kN·m -1According to one embodiment, the width-dependent breaking force along the fiber direction is between 3.5 and 5.5 kN·m -1 According to one embodiment, the width-dependent breaking force in the fiber direction is between 4.0 and 5.0 kN·m -1 range.

[0122] The barrier effect of the coating according to the invention is achieved by a coating as defined in accordance with the first aspect.

[0123] Therefore, according to a third aspect, the present invention relates to a coating for coating paper, comprising the components defined according to the first or second aspect and a solvent. The solvent is particularly selected from water, tetrahydrofuran (THF), ethanol, methanol and ethyl acetate. The solvent is preferably water.

[0124] Manufacturing method

[0125] Various manufacturing methods can be used to produce coated paper according to the present invention. The basic barrier effect of the coating in the coated paper is achieved in particular by the coated paper production method shown in the examples. Therefore, according to a fourth aspect, the present invention relates to a method for producing coated paper having a base paper and a coating, comprising the following steps:

[0126] a) producing a coating according to one of the third aspects by mixing the individual components;

[0127] b) Provide base paper;

[0128] c) applying the coating to the base paper, and

[0129] d) curing the coating to form a coating with a barrier effect.

[0130] According to one embodiment, the coating is applied to the base paper, preferably by curtain coating or knife coating.

[0131] The method according to the invention can be used to influence the properties of coatings.

[0132] In addition, curing temperature, curing time and curing pressure all have an impact on uniformity and barrier effect.

[0133] 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., 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.

[0134] According to one embodiment of the method, the curing time is in the scope of 10 seconds to 15 minutes. The curing time can be, for example, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds, 90 seconds, 100 seconds, 110 seconds, 120 seconds, 150 seconds, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes. According to one embodiment of the method, the curing time is 1 to 3 minute.

[0135] According to one embodiment of the method, the curing pressure is 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.

[0136] Package

[0137] According to a fifth aspect, the present invention relates to a package comprising the coated paper according to the first aspect or the second aspect.

[0138] This may be, for example, packaging for food products, for use as accessories for electronic components, such as silica gel packets, for medical products, such as rapid tests, for detergents and cleaning agents, in particular in powder or tablet form.

[0139] Furthermore, it may be a package of dry food, a cold-sale food requiring further processing, a package containing food for more than one person, or a package containing food for one person sold in more than one unit.

[0140] As packaging, for example, a stand-up pouch packaging, a tubular bag packaging or a wrapping paper can be used. According to one embodiment, the packaging is a tubular bag packaging.

[0141] Example

[0142] Example 1 - Raw materials and production of coating and barrier paper

[0143] Carrier material

[0144] In all examples, the carrier material used was clay-coated kraft paper (CCK), i.e. paper made of hardwood and softwood pulp coated with clay (coating weight: 5 g / m 2 ), the total unit area weight is 63g / m 2 .

[0145] Raw material preparation

[0146] All waxes and carboxylic acid derivatives were used in the form of aqueous dispersions which were stabilized by addition of polyvinyl alcohol (approximately 10% by weight; viscosity: 6-9 mPas; 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol %).

[0147] The dry matter content (TG) of the dispersion was adjusted by adding water as follows: candelilla wax (44%), carnauba wax (40%), stearic acid (25%), palmitic acid (25%), stearic acid amide (25%).

[0148] Shellac ( ASL 10, dewaxed and decolorized) was dissolved in ammonia water (TG = 25%).

[0149] Methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) were used as solids.

[0150] Polyethylene glycol (PEG) 400 was used without prior treatment.

[0151] Paint production

[0152] The solids content of the coatings was between 23% and 40%, depending on the system. No additional water was added after mixing the individual component dispersions. The coatings were sieved through a sieve with a mesh size of 80 μm and degassed using a Hauschild SpeedMixer at 30 mbar and 800 rpm for 4 minutes.

[0153] Coated base paper:

[0154] The coating (3-5 mL for DIN A4) was applied to the CCK-coated side of the base paper (DIN A3) at room temperature using a thin film applicator (Erichsen) with a doctor blade. The doctor blade was selected to achieve the desired 10 g / m 2 Coating Weight. The weights per unit area given are based on the dry layer.

[0155] After painting, the paper was attached directly to a commercially available thick paper with the aid of magnets (to prevent curling) and dried at 110° C. in a circulating air oven (Memmert; settings: 50% flap, 50% fan) until the barrier film was fully formed.

[0156] Example 2 - Barrier Effect of Comparative Coating Containing a Single Component

[0157] First, the water vapor barrier effect of coatings made from a single component carboxylic acid component (fatty acids and their derivatives), wax, and a natural resin (shellac) was tested.

[0158] To this end, a coating having the following composition was prepared as described in Example 1:

[0159] Shellac dissolved in ethanol (25% by weight)

[0160] Shellac dissolved in glacial acetic acid (25% by weight)

[0161] Dissolve shellac in 5% by weight ammonium bicarbonate solution (25% by weight),

[0162] Candelilla wax dispersion (26% by weight)

[0163] Carnauba wax dispersion (26% by weight)

[0164] Palmitic acid dispersion (25% by weight)

[0165] Stearic acid dispersion (25% by weight)

[0166] ·Stearic acid amide dispersion (25% by weight)

[0167] To produce coated paper, the coating was applied to the pre-coated base paper as described in Example 1. The coating weight was 10 g / m 2 The drying time is about 1-1.5 minutes at a temperature of about 110°C.

[0168] The water vapor transmission rate (WVTR) was determined under tropical conditions (38° C., 90% RH) according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96). The measurement results are shown in Table 1.

[0169] Table 1: WVTR of comparative barrier paper coatings made from individual components

[0170]

[0171] Barrier papers coated with shellac alone showed only a low water vapor barrier effect, with WVTR values ​​exceeding 200 g / m 2 d. In comparison, the WVTR of barrier papers containing layers of natural wax and fatty acids / fatty acid derivatives is significantly lower. However, especially in the case of coatings containing fatty acids, uneven film formation occurs, which leads to fluctuations in the WVTR of the barrier paper surface.

[0172] Example 3 - Characterization of a two-component coating according to the invention

[0173] 3.1 Two-component coating made from shellac and candelilla wax

[0174] 3.1.1. Application with a scraper

[0175] In this series of experiments, the water vapor barrier effect of a binary coating made of shellac and candelilla wax was tested.

[0176] Coatings with different ratios of shellac and candelilla wax and PVA [6-9 mPas (4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol%)] were prepared as described in Example 1. The ratios of candelilla wax dispersion to shellac in the composition were 0:100, 20:80, 40:60, 60:40, 80:20 and 100:0.

[0177] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was 10 g / m 2 .

[0178] In addition, the ratio of candelilla wax dispersion to shellac is 20:80, and the mixture is added at 5 to 30 g / m 2 The compositions were applied at different coating weights.

[0179] In the examples, drying is carried out at a constant temperature of 90-120° C. for a defined time. The drying time should be selected to be as short as possible, i.e. until the film is fully formed (visually recognizable by a uniform gloss) without further tempering. Tempering is the uniform heating of the material to a temperature below its melting temperature for a longer period of time (several minutes to several hours). Long drying times can result in impregnation, which has a negative impact on the barrier effect of the coated paper. In the present case, the drying time is in each case about 1-1.5 minutes at a temperature of about 110° C.

[0180] The water vapor transmission rate (WVTR) was determined according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96) under tropical conditions (38°C, 90% RH) using the cup method. Figure 1 and Figure 2 shown.

[0181] The results are as follows Figure 1 and Figure 2 shown.

[0182] By mixing shellac and wax dispersion, film formation and drying properties are improved when the coating is applied to carrier paper. In addition, the two-component coating has a significantly improved film-forming and drying performance at a coating weight of 10 g / m2 compared to the one-component coating. 2 The WVTR performance was better in the case of the wax dispersion. For WVTR, by varying the ratio of shellac to wax, the lowest value was determined for a ratio of 1:4 (20:80) of shellac to candelilla wax. By mixing the wax dispersion with shellac, it is also possible to reduce the proportion of PVA, which is process-related.

[0183] Coating weight also has a significant effect on WVTR. When coating weight is reduced to 5 g / m 2 When the WVTR increases from about 40g / m2d to more than 80g / m 2 d. In contrast, when increasing the coating weight, close to 0 g / m 2 d WVTR value. When the coating weight is about 15g / m 2 When , WVTR is the lowest.

[0184] 3.1.2. Application by curtain coating

[0185] By adding process additives known to those skilled in the art (e.g. thickeners and surfactants), the coating of the invention consisting of 80% candelilla wax dispersion and 20% shellac solution can be applied and dried by curtain coating, wherein the coating device is operated at a speed of at least 200 m / min. The WVTR of the resulting paper is 27.4±2.0 g / m 2 d.

[0186] Storage stability

[0187] The storage stability of coated papers produced according to 3.1.2 with a coating consisting of candelilla wax dispersion and shellac was investigated.

[0188] The water vapor barrier effect of the papers was tested after storage for 10, 75, 100, 150 and 200 days at 23° C. and 50% relative air humidity.

[0189] The results are as follows Figure 3 shown.

[0190] 3.2 Binary coating made of shellac and stearic acid

[0191] In this series of experiments, the water vapor barrier effect of a binary coating made of shellac and stearic acid was investigated.

[0192] For this purpose, coatings with different ratios of shellac and stearic acid were prepared as described in Example 1. The exact composition is given in Table 2.

[0193] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was 10 g / m 2 .

[0194] At a temperature of about 90° C., the drying time was in each case about 2 to 2.5 minutes.

[0195] The WVTR was determined according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96) under tropical conditions (38°C, 90% RH).

[0196] Table 2: WVTR of dual barrier papers according to the invention

[0197] Shellac (%): stearic acid dispersion (TG = 25%) <![CDATA[WVTR(g / m 2 d)]]> 52.1 50:50 55±6 31.8 30:70 46±5 27.2 25:75 15±1 11.1 10:90 35±3

[0198] In the production of two-component coatings made of shellac and stearic acid, improved film formation and drying properties were observed compared to single-component coatings. On the other hand, when the coating weight was 10 g / m 2 The two-component coating has an improved WVTR when the ratio of shellac to stearic acid dispersion is 2:3 (25:75). It is assumed that the addition of shellac limits the crystallization of stearic acid on the surface, thus improving the water vapor barrier and the uniformity of the application. For the WVTR, by varying the ratio of shellac to stearic acid dispersion, the lowest value was determined when the ratio of shellac to stearic acid was approximately 1:3 (25:75). By mixing stearic acid with shellac, it is also possible to reduce the proportion of PVA, which is process-related.

[0199] 3.3 Binary coating made of shellac and stearic acid amide

[0200] In this series of experiments the water vapor barrier effect of a binary coating made of shellac and stearic acid amide was investigated.

[0201] For this purpose, coatings with different ratios of shellac and stearic acid amide and PVA (6-9 mPas in 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol %) were prepared as described in Example 1. The ratios of shellac to stearic acid amide dispersion in the compositions were 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 0:100.

[0202] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was 10 g / m 2 .

[0203] In addition, a 50:50 ratio of shellac to stearamide dispersion and 1 to 20 g / m 2 The composition was applied at different coating weights.

[0204] In the examples, drying is carried out at a constant temperature of 130° C. for a defined time. The drying time should be selected to be as short as possible, i.e. until the film is fully formed (visually recognizable by a uniform gloss) without further tempering. Longer drying times can lead to impregnation, which has a negative effect on the barrier effect of the coated paper. In the present case, the drying time is in each case about 2-3 minutes at a temperature of about 130° C.

[0205] The water vapor transmission rate (WVTR) was determined according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96) under tropical conditions (38° C., 90% RH) using the cup method.

[0206] The results are listed in Tables 3 and 4.

[0207] Table 3: WVTR of barrier papers according to the invention having a dual coating of shellac and stearamide dispersion in different proportions at a coating weight of 10 g / m 2

[0208]

[0209]

[0210] By mixing shellac with stearamide dispersion, the film formation and drying properties of the coating are improved when applied to carrier paper. In addition, compared with a single-component coating, the film formation and drying properties of the coating are improved at a coating weight of 10 g / m 2 The two-component coating has an improved WVTR when the ratio of shellac to stearamide is varied. For the WVTR, it was possible to determine the lowest WVTR value at a ratio of 1:1 (50:50). By mixing stearamide dispersion with shellac, it is also possible to reduce the proportion of PVA in a process-related manner.

[0211] Table 4: WVTR as a function of coating weight for barrier papers according to the invention with a dual coating made from 50% shellac and 50% stearamide dispersion,

[0212] <![CDATA[Coating weight (unit: g / m 2 )]]> <![CDATA[WVTR 热带 , unit: g / m 2 d]]> 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

[0213] Coating weight has a significant effect on WVTR. When the application amount is reduced to 7g / m 2 When the WVTR is below 55g / m 2 d increases to more than 90g / m 2 d. In contrast, by increasing the coating weight, less than 40 g / m 2 The coating weight here is about 20 g / m 2 .

[0214] Example 4 - Characterization of ternary coatings according to the invention

[0215] 4.1 Ternary system made of candelilla wax, carnauba wax and shellac

[0216] In this series of experiments, the water vapor barrier effect of a ternary coating made of candelilla wax, carnauba wax, and shellac was investigated.

[0217] Coatings with different proportions of candelilla wax, carnauba wax and shellac and PVA (6-9 mPas, 4% aqueous solution; degree of hydrolysis: 86.7-88.7 mol%) were prepared as described in Example 1. The proportions of the components in the composition are shown in Table 3.

[0218] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was 10 g / m 2 .

[0219] The drying time was about 1-2 minutes at a temperature of about 110°C.

[0220] The water vapor transmission rate (WVTR) was determined under tropical conditions (38° C., 90% RH) according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96).

[0221] Table 5: WVTR of ternary barrier paper according to the present invention

[0222]

[0223] Barrier paper with a ternary layer made of shellac, candelilla wax and carnauba wax at a coating weight of 10 g / m 2 Very low WVTR values, less than 20 g / m 2 d. In addition, oil repellency according to the palm kernel fat test (EN ISO 53116) can be achieved with these ternary layers.

[0224] 4.2 Ternary system prepared from candelilla wax, stearic acid and shellac

[0225] In this series of experiments, the water vapor barrier effect of a ternary coating made of candelilla wax, stearic acid, and shellac was tested.

[0226] To this end, coatings with different ratios of candelilla wax, stearic acid and shellac were prepared as described in Example 1. The proportions of the components in the composition are shown in Tables 4 and 5.

[0227] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was constant at 10 g / m 2 The drying time was in each case about 1 to 2 minutes at a temperature of about 120° C.

[0228] The water vapor transmission rate (WVTR) was determined under tropical conditions (38° C., 90% RH) according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96). The results are listed in Tables 6 and 7.

[0229] Table 6: WVTR of high shellac concentration ternary barrier papers according to the invention

[0230]

[0231]

[0232] Table 7: WVTR of low shellac concentration ternary barrier papers according to the invention

[0233]

[0234] Barrier paper with a three-layer made of shellac, candelilla wax and stearic acid at a coating weight of 10 g / m 2 Very low WVTR values, less than 20 g / m 2 d. In addition, the composition of certain layers, especially those containing a high proportion of shellac and / or stearic acid, allows the coating to have good water-based barrier properties, such as oxygen barriers or sealing media. Although shellac as a single component has poor water vapor barrier properties and high WVTR values, in the ternary system, even with a shellac proportion of 50%, values ​​below 20 g / m 2 d’s WVTR value.

[0235] Example 5: Characterization of coatings containing film formers according to the invention

[0236] 5.1 Changes in film-forming agent composition

[0237] In this series of experiments, the effect of film formers on the water vapor barrier performance of stearic acid coatings was investigated.

[0238] To this end, a coating having the basic composition in Table 8 was prepared as described in Example 1:

[0239] Table 8: Basic composition

[0240]

[0241] The MC and HPMC used have the following differences:

[0242] HPMC1: viscosity (2% aqueous solution) 3 mPas; DS = 1.9; MS = 0.23

[0243] HPMC2: viscosity (2% aqueous solution) 50 mPas; DS = 1.9; MS = 0.23

[0244] HPMC3: viscosity (2% aqueous solution) 50 mPas; DS = 1.8; MS = 0.13

[0245] MC1: Viscosity (2% aqueous solution) 4 mPas; DS = 1.8

[0246] MC2: Viscosity (2% aqueous solution) 25 mPas; DS = 1.8

[0247] MC3: Viscosity (2% aqueous solution) 400 mPas; DS = 1.8

[0248] To produce coated paper, the coating was applied to base paper as described in Example 1. The coating weight was 10 g / m 2 The drying time is about 1-1.5 minutes at a temperature of about 110°C.

[0249] The water vapor transmission rate (WVTR) was determined under tropical conditions (38° C., 90% RH) according to DIN 53122 1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96). The results are shown in Table 9.

[0250] Table 9: Effect of film formers on WVTR

[0251] <![CDATA[WVTR value, unit: g / m 2 d]]> MC1 MC2 MC3 HPMC1 31±5 53±9 57±16 HPMC2 14±1 36±14 50±7 HPMC3 20±5 13±2 11±1

[0252] The results showed that the WVTR of barrier paper decreased with the increase of the viscosity of MC and HPMC used.

[0253] 5.2 Changes in fatty acid composition

[0254] The experiment corresponds to that described in 5.1. Instead of stearic acid, palmitic acid or a mixture of these two fatty acids was used.

[0255] Table 10: Coating composition

[0256]

[0257]

[0258] With regard to further advantageous embodiments of the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetitions.

[0259] Finally, it should be clearly pointed out that the working embodiments described above for the product according to the present invention are only used to explain the teachings claimed for protection, but do not constitute limitations thereto.

Claims

1. A coated paper comprising a base paper and at least one coating layer applied directly or indirectly to 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 selected from the group consisting of shellac, rosin, balsam, lac, rosin, sandarac, frankincense, conifer resin, dammar, gum arabic and elemi; in, The coated paper has a reduced permeability to at least one gas compared to the base paper.

2. A coated paper comprising a base paper and at least one coating layer applied directly or indirectly to 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 cellulose derivative as film former; in, The coated paper has a reduced permeability to at least one gas compared to the base paper.

3. The coated paper according to claim 1 or 2, wherein the coating further comprises a polymer stabilizer.

4. Coated paper according to any of the preceding claims, wherein the permeability of the coated paper to at least one gas is lower than the permeability of a coated paper having the same base paper and having respectively a coating layer made of a natural wax or a saturated fatty acid and a coating layer made of a natural resin.

5. The coated paper according to any one of the preceding claims, having a coating weight per unit area of ​​10±1 g·m at 38°C, over 90% air humidity and 10±1 g·m -2 The measured value is not more than 50g·m -2 ·d -1 , preferably not more than 20g·m -2 ·d -1 Water vapor transmission rate (WVTR).

6. A coated paper according to any one of the preceding claims, wherein the carboxylic acid component is selected from fatty acids, hydroxy fatty acids or dicarboxylic acids or their esters, amides or salts.

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

8. Coated paper according to any one of the preceding claims, wherein the natural wax is selected from carnauba wax, candelilla wax, beeswax, China wax and Japan wax.

9. The coated paper according to any one of claims 2 to 8, wherein the polymer stabilizer is a cross-linked or uncross-linked stabilizer selected from the following group: polyvinyl alcohol, starch, carboxyl-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, α-isodecyl-ω-hydroxy-poly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, carboxyl-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, silanol-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyethylene glycol, unmodified polyethylene glycol, α-isodecyl-ω-hydroxy-poly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer and mixtures thereof and mixtures thereof.

10. The coated paper according to any one of claims 2 to 9, wherein the coating comprises a carboxylic acid component, a natural resin and optionally a polymer stabilizer, wherein: a) the proportion of the carboxylic acid component relative to the total mass of the coating is in the range of 25 to 75% by weight, preferably in the range of 30 to 75% by weight, particularly preferably in the range of 40 to 65% by weight, b) the proportion of natural resin relative to the total mass of the coating is in the range of 20 to 60% by weight, preferably in the range of 25 to 55% by weight, particularly preferably in the range of 30 to 50% by weight, and / or b) The proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight, preferably in the range of 1 to 15% by weight, particularly preferably in the range of 2 to 10% by weight.

11. A coated paper according to any one of claims 2 to 9, wherein the coating comprises a natural wax, a natural resin and optionally a polymer stabilizer, wherein: a) the proportion of the natural wax relative to the total mass of the coating is in the range of 40 to 95% by weight, preferably in the range of 60 to 90% by weight, particularly preferably in the range of 50 to 85% by weight, very particularly preferably in the range of 60 to 80% by weight; b) the proportion of natural resin relative to the total mass of the coating is in the range of 5 to 60% by weight, preferably in the range of 10 to 40% by weight, particularly preferably in the range of 20 to 40% by weight, and / or b) The proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight, preferably in the range of 1 to 15% by weight, particularly preferably in the range of 2 to 10% by weight.

12. Coated paper according to any one of claims 1 to 11, wherein the coating comprises at least one cellulose derivative as film former selected from methyl cellulose (MC), ethyl cellulose (EC), methyl ethyl cellulose (MEC), hydroxyethyl cellulose (HEC), hydroxymethyl cellulose (HMC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), wherein the coating preferably comprises two cellulose derivatives as film formers, wherein the film formers are MC and CMC.

13. The coated paper according to claim 12, wherein the coating comprises a carboxylic acid component, two cellulose derivatives as film formers and at least one polymer stabilizer, wherein: a) the proportion of the carboxylic acid component relative to the total mass of the coating is in the range of 75 to 98% by weight, preferably in the range of 80 to 95% by weight, particularly preferably in the range of 85 to 92% by weight, very particularly preferably in the range of 87 to 90% by weight; b) the proportion of film former relative to the total mass of the coating is in the range of 0.2 to 5.0% by weight, preferably in the range of 0.3 to 2.0% by weight, particularly preferably in the range of 0.3 to 1.0% by weight, very particularly preferably; and / or b) The proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight, preferably in the range of 5 to 15% by weight, particularly preferably in the range of 7 to 13% by weight.

14. A coated paper according to any one of claims 1 and 3 to 9, wherein the coating comprises: a) at least two natural waxes or a 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 comprises two natural waxes, a natural resin and optionally a polymer stabilizer, wherein: a) the proportion of the natural wax, relative to the total mass of the coating, is in the range of 15 to 60% by weight, preferably in the range of 25 to 55% by weight, particularly preferably in the range of 35 to 55% by weight, very particularly preferably in the range of 40 to 50% by weight; b) the proportion of natural resin relative to the total mass of the coating is in the range of 30 to 85% by weight, preferably in the range of 40 to 70% by weight, particularly preferably in the range of 45 to 60% by weight; and / or b) The proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight, preferably in the range of 1 to 15% by weight, particularly preferably in the range of 2 to 10% by weight.

16. The coated paper according to claim 15, comprising a natural wax, a carboxylic acid component, a natural resin and optionally a polymer stabilizer, wherein: a) the proportion of the natural wax, relative to the total mass of the coating, is in the range of 2 to 70% by weight, preferably in the range of 5 to 35% by weight, particularly preferably in the range of 5 to 25% by weight, very particularly preferably in the range of 7 to 20% by weight; b) the proportion of the carboxylic acid component relative to the total mass of the coating is in the range of 5 to 75% by weight, preferably in the range of 15 to 70% by weight, particularly preferably in the range of 25 to 65% by weight, very particularly preferably in the range of 30 to 40% by weight; and / or c) the proportion of natural resin relative to the total mass of the coating is in the range of 5 to 65% by weight, preferably in the range of 7 to 60% by weight, particularly preferably in the range of 8 to 55% by weight; and / or d) The proportion of the polymer stabilizer relative to the total mass of the coating is less than 20% by weight, preferably in the range of 1 to 15% by weight, particularly preferably in the range of 2 to 10% by weight.

17. A coated paper according to any one of the preceding claims, wherein The coating has a unit area weight of 2 to 30 g·m -2 The range is preferably between 5 and 20 g·m -2 In the range of 8 to 15 g·m -2 within the range.

18. The coated paper according to any one of the preceding claims, wherein the coated paper has at least one of the following features: The coated paper is biodegradable, in particular it has ready biodegradability according to OECD 301; The coated paper is capable of being recycled; and The coated paper is capable of being approved for direct or indirect contact with food, in particular according to European Food Safety Authority guidelines.

19. A coating for coating paper comprising a component as defined in any one of claims 1 to 16 and a solvent selected from water, tetrahydrofuran (THF) and ethanol, wherein the solvent is preferably water.

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

21. A package comprising a coated paper according to any one of claims 1 to 18.

22. A package according to claim 21 for food products; as an accessory for electronic components, such as a silica gel pack; for medical products, such as rapid tests; for detergents and cleaning agents, in particular in powder or tablet form.

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