Bio-based composites as water vapor barriers on paper

Abstract

This application relates to a coated paper comprising a base paper and at least one coating layer applied indirectly or directly to the base paper. 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, and the coated paper has reduced permeability to at least one gas compared to the base paper. This application also relates to a coating composition used in producing such a coated paper, a production method, and the resulting packaging.

Description

[Technical Field]

[0001] The present invention relates to coated paper that has high barrier properties against gases and moisture and can be used as a packaging material. [Background technology]

[0002] Packaging is a major contributor to global plastic waste pollution, prompting the development of biodegradable alternatives.

[0003] Food packaging, in particular, poses a major challenge because it requires excellent barrier properties against oxygen, water vapor, and microorganisms.Plastics commonly used for food packaging, such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP), not only offer excellent barrier properties but also are lightweight and highly mechanically stable.

[0004] On the other hand, paper-based packaging materials offer many advantages over plastic materials, such as renewable, recyclable and compostable nature, but their use is often limited by their generally poor barrier properties and susceptibility to moisture.

[0005] To improve barrier properties, paper-based packaging materials are sometimes laminated with aluminum or petroleum-derived polymers such as PE, EVOH, and PVC derivatives. However, these coatings complicate waste sorting and recycling, and make composting difficult. Replacing the traditional metal or plastic layers with barrier layers made from natural or bio-based polymers is highly desirable from an environmental perspective.

[0006] Examples of natural polymers that have been tested for packaging applications include chitosan, hemicellulose, microfibrillated cellulose, starch, etc. However, many natural polymers are hydrophilic, and films obtained from them are often hygroscopic, partially degrading their barrier performance under high humidity.

[0007] JP 2006-096981 A discloses a coating solution that provides moisture resistance to substrates such as films, sheets, paper, textiles, and nonwoven fabrics. The main components of the coating solution are shellac and paraffin wax. To achieve the desired moisture resistance, the applied layer must be heat-treated at a temperature of at least 90°C for at least 5 seconds. The water vapor transmission rate is 50 g / (m 2 Although it is intended that the shelf life be less than 10 days, paper coated in this way is not very biodegradable.

[0008] International Application No. 2020 / 152292A1 describes barrier papers for use as food packaging. These barrier papers consist of a paper substrate with a mass ratio of at least 90% cellulose fibers and a barrier layer disposed on the front and / or back surface of the paper substrate. The barrier layer contains a polymeric stabilizer such as polyvinyl alcohol or starch and at least one wax or vegetable oil such as beeswax, olive oil, soybean oil, or rapeseed oil. The barrier paper has a water vapor transmission rate of 150 g / (m²) as measured according to DIN 53122-1. 2 The aim is to keep the figure at or below 100,000 (days), but no substantiated data for these figures has been provided.

[0009] International Application No. 2020 / 011824A1 discloses a packaging system comprising a first paper layer containing particulate activated carbon, a first barrier layer disposed on the first paper layer and containing a binder and a pigment, and a second barrier layer disposed on the first barrier layer and containing an acrylic copolymer and a wax. The barrier paper has a water vapor transmission rate of 125 g / (m2) measured according to DIN 53122-1 at 23°C and 85% humidity. 2 The aim is to keep the number of people taking the drug below 100 (days), but again, no data to support the figures is provided.

[0010] US Patent 9,902,815 B2 and the scientific paper "Hult et al. 2013" by the same authors describe a method for the esterification of lignin with a mixture of fatty acids, in particular tall oil fatty acids, the main components of which are unsaturated fatty acids such as oleic, linoleic and linolenic acids, which are reacted with lignin at various degrees of esterification.

[0011] German patent application 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 point of the crystallizable material, the viscosity of the polymer is at most 10 12 mPa·s. This results in a superhydrophobic and recyclable layer. However, these layers have very limited gas barrier properties. Summary of the Invention

[0012] The present invention is based on the surprising discovery that combining at least one natural wax or carboxylic acid component with at least one natural resin results in a coating that exhibits a high barrier effect against gases and moisture while maintaining biodegradability. Coated papers produced using the coatings of the present invention exhibit barrier properties sufficient for use in the food industry, while also being biodegradable and recyclable. The coatings of the present invention may be two-component or three-component systems consisting of a natural resin, a natural wax, and a carboxylic acid component. Ternary systems, in particular, may exhibit a higher barrier effect and potentially impart additional properties to the coated paper, such as improved oil resistance.

[0013] Thus, according to a first aspect of the present invention, there is provided a coated paper comprising a base paper and at least one coating layer applied directly or indirectly onto the base paper. a) at least one natural wax and / or at least one carboxylic acid component; b) at least one natural resin wherein the coated paper has a reduced permeability to at least one gas compared to the base paper.

[0014] Even more surprisingly, even when natural resins are not used, coated paper having equivalent barrier properties against gases and moisture can be obtained by applying a natural wax or a carboxylic acid component together with at least one film-forming agent, particularly a cellulose derivative, to a base paper as a coating layer. According to a second aspect of the present invention, there is provided coated paper comprising a base paper and at least one coating layer applied directly or indirectly on the base paper. The coating layer is a) at least one natural wax and / or at least one carboxylic acid component; b) at least one film-forming agent, in particular a cellulose derivative wherein the coated paper has a reduced permeability to at least one gas compared to the base paper.

[0015] The barrier effect and biodegradability envisaged in the present invention are achieved by the two-component or three-component coating compositions described above and suitable solvents.

[0016] Thus, in a third aspect of the present invention there is provided a paper coating composition comprising the ingredients defined in the first or second aspect and a solvent (preferably water) selected from water, tetrahydrofuran (THF), ethanol, methanol and ethyl acetate.

[0017] The important barrier properties of the coating layer of the coated paper in the present invention are obtained particularly by the method for producing the coated paper used in the present invention. Thus, in a fourth aspect of the present invention, there is provided a method for producing coated paper having a base paper and a coating layer, the method comprising the steps of: a) mixing the individual components to prepare a coating composition; b) providing a base paper; c) applying the coating composition to the base paper by curtain coating or blade coating; d) A step of curing the coating composition to form a coating layer.

[0018] Furthermore, according to a fifth aspect of the present invention, there is provided a packaging body comprising the coated paper according to the first or second aspect. [Brief explanation of the drawings]

[0019] [Figure 1] 3 shows a graph of the water vapor transmission rate (WVTR) measurements of shellac-coated papers prepared using a two-component coating layer derived from candelilla wax, as shown in Example 3.1, with varying shellac to candelilla wax ratios, with the coating weight held constant. [Figure 2] This graph shows the WVTR measurement results for shellac-coated paper prepared using a two-component coating layer derived from candelilla wax, as shown in Example 3.1, when the coating weight was changed while the ratio of shellac to candelilla wax was kept constant. [Figure 3] Graph showing the WVTR measurement results versus storage time in Example 3. The results are shown for paper coated with a coating consisting of 80% candelilla wax dispersion and 20% shellac, measured 10, 50, 100, 150, 200, and 250 days after storage. Detailed Description of the Invention

[0020] <Definition> In the context of the present invention, and in line with common understanding in the papermaking art, the term "coating composition" refers to a coating agent that contains or consists of binders, additives, and, optionally, pigments and fillers, which is applied to the surface of paper using special coating equipment in order to finish or modify the surface. Paper produced in this way is called "coated paper."

[0021] In the context of the present invention, the term "coated paper" refers to a base paper that has been coated with one or more coating layers. The layers of such a coated base paper may include functional layers and structure-forming layers (e.g., compensation layers for smoothing the surface).

[0022] In the present invention, the term "coating composition" is used as a general term to refer to any spreadable coating composition, preparation, and / or solution used in the paper industry to treat, modify, or finish paper surfaces. The term "coating layer" refers to the coating composition that has been applied to the base paper, dried, and cured.

[0023] "Paper" means a flat material made mainly of plant-derived fibers and formed by dewatering a fiber suspension on a sieve. The resulting fiber web is compressed and dried to obtain paper. Within the scope of this invention, flat materials such as "karton" and "cardboard" produced by this process are also considered to be included in paper. Paper, paperboard and cardboard are differentiated by their mass per square meter (basis weight). Cardboard has a mass of 600 g / m². 2 and Karton is 150g / m 2 Over 600g / m 2 Below, paper (Papier) is 150g / m 2 It is defined as follows:

[0024] The "Water Vapor Transmission Rate (WVTR)" is an index that indicates how much water vapor passes through a material. To calculate the WVTR value, 2 It measures how much water evaporates per unit of mass, g / m 2·day (grams per square meter per day). Unless otherwise specified in the present invention, WVTR is measured in accordance with DIN 53122-1 / DIN 53122A (related: ISO 2528:1995, ASTM E 96) under so-called tropical conditions of 38°C and 90% relative humidity (RH). The term "water vapor permeability" is used synonymously with WVTR.

[0025] In the present invention, a surface that exhibits a contact angle with water of 145° or greater, preferably 150° or greater, is called "superhydrophobic." When such a high contact angle is exhibited, typically only about 2-3% of the water droplet surface comes into contact with the superhydrophobic surface. In other words, the surface is extremely resistant to wetting. Furthermore, a superhydrophobic surface is characterized by a sliding angle (described below) of less than 10°.

[0026] In the present invention, the term "contact angle" refers to the angle between the base of a liquid droplet placed on a surface and the boundary between the surface and the horizontal. It is measured in degrees (°) and depends on several factors, including the surface tension and surface properties of the liquid.

[0027] In this invention, "sliding angle" refers to the angle at which a droplet rolls off a surface when the surface is tilted beyond a certain angle. This is usually used to describe the characteristics of a superhydrophobic surface, where a droplet maintains an approximately spherical shape as it rolls along the surface. Even when the contact angle is somewhat small, the droplet may still move across the surface, but in this case, the droplet first deforms and then slides along the surface. When the sliding angle is 180°, the droplet will not fall even if it is turned upside down, but will remain attached to the coating layer.

[0028] <Coated paper and coating composition> According to a first aspect of the present invention, there is provided 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 is a) at least one natural wax and / or at least one carboxylic acid component; b) at least one natural resin; and the coated paper has a reduced permeability to at least one gas compared to the base paper.

[0029] In one form of coated paper, when compared at the same total coating weight, the permeability of the coated paper to at least one gas is lower than that of a coated paper having, on the same base paper, a coating layer made only of natural resin and a coating layer made only of natural wax and / or carboxylic acid component. Because of this effect, the coating layer of the present invention is also called a "barrier layer."

[0030] The coating layer reduces the permeability of the coated paper to at least one gas, such as oxygen (O2), nitrogen (N2), carbon dioxide (CO2), methane (CH4), hydrogen (H2), water vapor, or mixtures thereof (such as air), compared to the base paper. In particular, the water vapor transmission rate (WVTR) is reduced.

[0031] This specification suggests that combining at least one natural resin can prevent the natural wax and carboxylic acid components from crystallizing on the surface. While a crystalline structure creates fine irregularities on the surface, making it super-water-repellent, it has the problem of being difficult to form a uniform, continuous coating necessary to prevent gas permeation. Therefore, the idea is that combining it with a resin homogenizes the surface, preventing the permeation of water vapor molecules.

[0032] Therefore, the surface of the coating layer is not superhydrophobic, and the contact angle with water does not exceed 150°. Examples of contact angles include 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, and 145°. Surfaces exceeding 145° are generally considered superhydrophobic, so in the present invention, the contact angle preferably does not exceed 145°. In some embodiments, the contact angle may be 130° or less, or in other embodiments, 115° or less.

[0033] Furthermore, the sliding angle of the coating layer for a 4 μL water droplet is preferably greater than 10°. Examples of the sliding angle include 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°, and 180°. In one embodiment, the sliding angle is greater than 20°, or in another embodiment, greater than 40°, or in another embodiment, greater than 60°.

[0034] The use of these bio-based materials allows for the utilization of highly recyclable and biodegradable materials, reducing plastic pollution in the environment. Furthermore, as exemplified by the use of natural resins, it is possible to reduce the amount of stabilizers used, which are often poorly biodegradable.

[0035] The coated paper obtained by using the coating layer of the present invention exhibits high barrier performance, particularly a very low WVTR. In one embodiment, the coating weight of the coating layer is 10±1 g / m 2 In this case, the WVTR is 50g / (m 2 ·day).

[0036] For example, the WVTR of the coated paper of the present invention is 50, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1 g / (m 2 By appropriately selecting and adjusting the components and crystallinity of the coating composition, it is possible to reduce the WVTR to 20 g / (m 2 ·day) or less, even 10g / (m 2 It is possible to keep it below 1000kJ / day.

[0037] The natural resin is preferably a chemically / thermally crosslinkable organic matrix. In one embodiment, the natural resin is selected from shellac, turpentine, balsam, gummilack, colophonium, sandarak, mastic, resins derived from conifers, dammar, gum arabic, and elemi. A preferred example is shellac.

[0038] Shellac is a resinous substance secreted by the lac scale insect (Kerria lacca), a member of the Kerridae family, after feeding on certain plants. Its main components (65-75%) are free and esterified aliphatic and aromatic polyhydroxy acids, primarily aleuritic acid (up to approximately 32%) and sherolic acid. These monomers contain multiple hydroxyl and carboxyl groups, allowing them to form a three-dimensional network structure similar to thermosetting resins. Other components include pigments (4-8%), bitter components, and trace amounts of wax (shellac wax; a reddish-brown, brittle, and very hard ceryl lignocerate, ceryl cerotinate, and wax alcohols). Shellac is biodegradable.

[0039] Turpentine, strictly speaking, is a volatile oil obtained by distilling resins from coniferous trees, primarily those of the Pinaceae family. Its main components are terpenes, such as α-pinene and β-pinene, and are used as solvents and in the manufacture of paints and varnishes. Balsam is a general term for resins mixed with essential oils, which are extracted directly from tree trunks and branches by cutting into them or from natural secretions. Their chemical composition varies, but they often contain essential oils and resin acids. Balsam is primarily used in perfumery, pharmaceuticals, and cosmetics. Gummilack is a resin obtained by collecting sap from the bark of various lacquer trees and is used in the manufacture of paints, inks, and other products. It is composed of complex esters and polyphenolic compounds.

[0040] Colophonium is a resin obtained as a by-product of the distillation of turpentine, especially from coniferous trees. Its main components are resin acids, such as abietic acid, and it is used in electronics for soldering, in the music industry for stringed instruments, and in the chemical industry as an adhesive or binder.

[0041] Sandarak is a resin obtained primarily from cypress trees, particularly by incising the bark and tapping the sap, and is used in the manufacture of paints and incense. Chemically, it is composed primarily of terpenoids.

[0042] Mastic (Mastix) is a resin obtained primarily by tapping the mastic shrub (Pistacia lentiscus). Chemically, it is a mixture of resin acids, essential oils, and resin alcohols. It is used in the food industry as a natural additive and in cosmetics.

[0043] Coniferous resin is a general term for the resin secreted by coniferous trees such as pine, spruce, and fir, which may contain terpenes, resin acids, and sometimes essential oils. It is used in the production of terpenes and resin acids, as well as in paints and adhesives.

[0044] Dammar is a resin obtained from various tropical trees, particularly by cutting into the bark. Chemically, it is composed of a mixture of terpenes and resin acids and is used as a paint or adhesive.

[0045] Gum arabic (Gummi arabicum) is a resin obtained by tapping the bark of several species of trees, mainly from the Acacia genus. Chemically, it is a complex polysaccharide that may contain proteins. It is used as a thickener in the food industry and as a binder in the printing industry.

[0046] Elemi is a resin obtained from tropical trees belonging to the Canarium genus. Chemically, it is a mixture of terpenes, resin acids, and essential oils. It is used in the perfume and cosmetics industries.

[0047] Although these resins have different chemical compositions, they have similar physicochemical properties to shellac and can be used as binders, adhesives, coating agents, etc.

[0048] Examples of carboxylic acid components that can be used in the present invention include 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, dicarboxylic acids and their dicarboxylic acid esters, dicarboxylic acid amides, dicarboxylic acid salts, etc. Examples of dicarboxylic acids that can be used in the present invention include tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, icosanediic acid, docosanediic acid, etc.

[0049] The carboxylic acid component can be a saturated or unsaturated fatty acid having 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, lignochelic acid, cerotic acid, montanic acid, melissic acid, lacqueric acid, and geddinic acid. Examples of unsaturated fatty acids include myristoleic acid, palmitoleic acid, margaroleic acid, petroselinic acid, oleic acid (OA), elaidic acid, vaccenic acid, gadoleic acid, gondoic acid, cetoleic acid, erucic acid, and nervonic acid. Additional examples include linoleic acid (LA), alpha-linolenic acid (ALA), gamma-linolenic acid (GLA), calendullic acid, punicic acid, alpha-eleostial acid, beta-eleostial acid, stearidonic acid, arachidonic acid, eicosapentaenoic acid (timnodonic acid, EPA), docosadienoic acid, docosatetraenoic acid (adrenic acid, ADA), docosapentaenoic acid (clopanodonic acid), (DPA-3) docosahexaenoic acid (cervonic acid, clopanodonic acid, DHA), and tetracosahexaenoic acid (nisinic acid).

[0050] In one embodiment, the fatty acid used as the carboxylic acid component has 16 to 18 carbon atoms and zero or one double bond. In another embodiment, the fatty acid is selected from margaric acid, stearic acid, palmitic acid, linoleic acid, α-linolenic acid, and γ-linolenic acid. In yet another embodiment, the carboxylic acid component may be stearic acid or its amide or salt.

[0051] The fatty acid salts in the present invention include chromium (III) chloride complexes with fatty acids, aluminum salts, calcium salts, sodium salts, potassium salts, ammonium salts, etc. Preferred fatty acid salts are monovalent salts of sodium, potassium, and ammonium ions.

[0052] In some embodiments, a mixture of fatty acids is used. Examples include mixtures of stearic acid, palmitic acid, oleic acid, linoleic acid, and linolenic acid. Specific examples 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, and a mixture of stearic acid, oleic acid, and linoleic acid. A preferred mixture is a mixture of stearic acid and palmitic acid.

[0053] Waxes that can be used in the present invention include carnauba wax, candelilla wax, beeswax, China wax (Chinese wax), Japan wax (wood wax), etc. Carnauba wax or candelilla wax is preferably used.

[0054] In some embodiments, crosslinked or non-crosslinked polymeric stabilizers are used to prevent agglomeration of the finely dispersed components in the coating composition, and at higher levels, the stabilizer may also function as a binder. Examples of polymer stabilizers include 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, α-isodecyl-ω-hydroxypoly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, 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, α-isodecyl-ω-hydroxypoly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, and mixtures thereof. Among these, polyvinyl alcohol is preferably used in some embodiments. Various types of polyvinyl alcohol with different degrees of hydrolysis and viscosities are commercially available, and preferred are those with a viscosity of 2 to 10 mPa·s measured in a 4% aqueous solution (20°C, DIN 53015 / JIS K 6) and a degree of hydrolysis of 80 mol% or more. Examples of commercially available products include KURARAY POVAL (registered trademark) 6-88 and KURARAY POVAL (registered trademark) 6-98.

[0055] In some embodiments, the coating layer comprises a carboxylic acid component, a natural resin, and, optionally, a polymer stabilizer. The carboxylic acid component may comprise 15 to 85% by weight of the total weight of the coating layer. For example, the carboxylic acid component may comprise 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% by weight. More preferred ranges include 25 to 75%, 30 to 75%, and 40 to 65% by weight.

[0056] In two-component coating layer formulations containing a carboxylic acid component, a natural resin, and optionally a polymeric stabilizer, the proportion of natural resin relative to the total coating layer weight can range from 10 to 70% by weight. For example, the natural resin can account for 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% by weight. More preferred ranges include 20 to 60%, 25 to 55%, or 30 to 50% by weight.

[0057] In two-component coating formulations containing a carboxylic acid component, a natural resin, and a polymeric stabilizer, the polymeric stabilizer may comprise less than 30 wt% of the total coating weight. For example, the polymeric stabilizer may comprise 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 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%. More preferred ranges include less than 20 wt%, 1-15 wt%, and 2-10 wt%.

[0058] In some embodiments, the two-component coating layer comprises a formulation containing natural wax, natural resin, and an optional polymer stabilizer. The proportion of natural wax relative to the total weight of the coating layer can range from 15 to 95% by weight, such as 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% by weight. More preferred ranges include 30 to 95%, 40 to 90%, 50 to 85%, and 60 to 80% by weight.

[0059] In coating layer formulations containing natural wax, natural resin, and optional polymeric stabilizer, the proportion of natural resin relative to the total weight of the coating layer can range from 5 to 70% by weight, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, and 70% by weight. More preferred ranges include 5 to 60%, 10 to 40%, and 20 to 40% by weight.

[0060] In coating layer formulations containing natural waxes, natural resins, and polymer stabilizers, the polymer stabilizer may be less than 30% by weight of the total coating layer mass, such as 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, or 28% by weight. More preferred ranges include less than 20% by weight, 1-15%, and 2-10% by weight.

[0061] In some embodiments, the coating layer includes at least one film-forming agent, particularly a cellulose derivative. Examples of cellulose derivatives include methyl cellulose (MC), ethyl cellulose (EC), methyl ethyl cellulose (MEC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), and hydroxyethyl methyl cellulose (HEMC). In some embodiments, the coating layer may include 1 to 10 film-forming agents. In other embodiments, the coating layer may include a combination of two film-forming agents, methyl cellulose and carboxymethyl cellulose.

[0062] In some embodiments of the present invention, the proportion of the film-forming agent relative to the total weight of the coating layer is in the range of 0.2 to 5.0 wt%. For example, the content of the film-forming agent may be 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%, 5.0 wt%, and the like. In some embodiments, the proportion of the film-forming agent relative to the total weight of the coating layer may be in the range of 0.3 to 2.0 wt%. In other embodiments, the proportion of the film-forming agent may be in the range of 0.3 to 1.0 wt%.

[0063] It has been surprisingly discovered that by using the film-forming agent used in the present invention, coated paper can be obtained that exhibits the same properties in terms of gas and moisture barrier effect as natural resins, even without using natural resins. Therefore, as a second aspect of the present invention, there is provided coated paper comprising a base paper and at least one coating layer applied directly or indirectly to the base paper. The coating layer comprises: a) at least one natural wax and / or at least one carboxylic acid component; b) at least one film-forming agent (especially a cellulose derivative); wherein the coated paper has reduced permeability to at least one gas compared to the base paper.

[0064] In this case, a film-forming agent is used instead of the natural resin, and otherwise, unless otherwise specified, the coating of the coated paper according to the second aspect has the same properties as the coating of the coated paper according to the first aspect.

[0065] In one embodiment, the coating layer comprises a carboxylic acid component, at least two film-forming agents (especially cellulose derivatives), and at least one polymeric stabilizer.

[0066] In such a composition, the proportion of the carboxylic acid component relative to the total weight of the coating layer can be in the range of 75 to 98 wt%. For example, the carboxylic acid component can be 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%. In one embodiment, the proportion is in the range of 85 to 92 wt%, in another embodiment, in the range of 87 to 90 wt%, and in yet another embodiment, in the range of 40 to 65 wt%.

[0067] In coating formulations containing a carboxylic acid component, two film-forming agents, and optionally a polymeric stabilizer, the film-forming agent content can range from 0.2 to 5.0 wt% of the total coating weight, e.g., 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%, 5.0 wt%, etc. In some embodiments, the film-forming agent content ranges from 0.3 to 2.0 wt%, and in other embodiments, the film-forming agent content ranges from 0.3 to 1.0 wt%.

[0068] In coating layer formulations containing a carboxylic acid component, a natural resin, and a polymeric stabilizer, the polymeric stabilizer can be present in an amount less than 30% by weight of the total coating layer weight. For example, the polymeric stabilizer can be present in an amount of 0.1%, 0.5%, 1%, 1.5%, 2.0%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or the like. A slightly higher proportion of polymeric stabilizer may be advantageous compared to barrier layers containing natural resins. In some embodiments, the amount is less than 20% by weight, in other embodiments, in the range of 5-15% by weight, and in yet other embodiments, in the range of 7-13% by weight.

[0069] In some embodiments of the coated paper according to the first aspect, the coating is a ternary coating, comprising at least two natural waxes or at least one natural wax and one saturated fatty acid, and at least one natural resin. The ternary system provided by the invention allows for further reductions in the proportion of polymeric stabilizers. It also allows for the creation of layers that can be directly overcoated. The tunable coating composition allows for variations in the availability of each component while maintaining the same barrier performance (WVTR). Additionally, these ternary coatings also exhibit oil resistance.

[0070] In some embodiments of the coated paper according to the first aspect, the coating layer may comprise two natural waxes, one natural resin, and, optionally, a polymeric stabilizer. In this formulation, the proportion of natural waxes relative to the total weight of the coating layer may range from 10 to 80% by weight. For example, the carboxylic acid component may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or the like. In some embodiments, the proportion of natural waxes may range from 15 to 60%, 25 to 55%, 35 to 55%, or even 40 to 50% by weight.

[0071] Additionally, in coating layer formulations containing two natural waxes, a natural resin, and optionally a polymeric stabilizer, the proportion of natural resin relative to the total weight of the coating layer can range from 20 to 90% by weight, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc. In some embodiments, the proportion is in the range of 30 to 85%, 40 to 70%, or 45 to 60% by weight.

[0072] In coating formulations containing two natural waxes, a natural resin, and a polymeric stabilizer, the polymeric stabilizer may be present in an amount less than 30% by weight of the total coating weight, such as 0.1%, 0.5%, 1%, 1.5%, 2.0%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, etc. In some embodiments, the polymeric stabilizer is present in an amount less than 20% by weight, in other embodiments, 1-15% by weight, and in yet other embodiments, 2-10% by weight.

[0073] In yet another embodiment, the three-component coating layer comprises a carboxylic acid component, a natural wax, a natural resin, and, optionally, a polymeric stabilizer. In this case, the proportion of the carboxylic acid component relative to the total weight of the coating layer is preferably in the range of 5 to 85% by weight. For example, it may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% by weight. In one embodiment, it is in the range of 55 to 75% by weight, 15 to 70% by weight in another embodiment, 25 to 65% by weight in yet another embodiment, or 30 to 40% by weight in still another embodiment.

[0074] In this formulation, the proportion of the natural wax relative to the total weight of the coating layer may be in the range of 15 to 95% by weight. For example, the amount of the carboxylic acid component may 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, 95% by weight, etc. In one embodiment, the range is preferably 30 to 95% by weight, in another embodiment, 40 to 90% by weight, in yet another embodiment, 50 to 85% by weight, or in still another embodiment, 60 to 80% by weight.

[0075] In coating layers containing a carboxylic acid component, a natural wax, a natural resin, and optionally a polymeric stabilizer, the proportion of the natural resin relative to the total weight of the coating layer can range from 5 to 70% by weight, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc. In one embodiment, the proportion is 20 to 60% by weight, in another embodiment, 25 to 55% by weight, and in yet another embodiment, 30 to 50% by weight.

[0076] In addition, in coating layer formulations containing a carboxylic acid component, natural wax, natural resin, and polymer stabilizer, the proportion of the polymer stabilizer relative to the total weight of the coating layer can be adjusted to less than 30 wt %. For example, the proportion can be 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 %, 28 wt %, etc. In some embodiments, the proportion is less than 20 wt %, in another embodiment, in the range of 1 to 15 wt %, and in yet another embodiment, in the range of 2 to 10 wt %.

[0077] The coating layer of coated paper is 2 to 30 g / m 2 For example, the coating amount can be 2 g / m 2 , 4g / m 2 , 5g / m2 , 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 , 30g / m 2 In one embodiment, the coating amount of the coating layer is 2 to 30 g / m 2 In another embodiment, the amount is in the range of 5 to 20 g / m 2 In another embodiment, the range is 8 to 15 g / m 2 is in the range.

[0078] Coated paper according to the first or second aspect of the present invention is biodegradable due to the materials contained in the coating layer. "Biodegradability" refers to the ability of organic compounds to be broken down by living organisms or their enzymes. Ideally, this chemical metabolism proceeds completely, leading to mineralization, but transformation products that are difficult to decompose may remain. The OECD guidelines for the testing of chemicals are widely recognized standards and are used in the approval of chemicals. OECD Test Series 301 (A-F) provides several test methods for determining whether a substance demonstrates rapid and complete biodegradability under aerobic conditions. These tests offer options tailored to the characteristics of substances, such as those that are soluble or sparingly soluble in water, or those that are volatile. Paper referred to herein as "biodegradable" or "biologically degradable" means paper that has an "intrinsic or fundamental degradability" (inharente oder grundsatzliche Abbaubarkeit) of at least 40% when measured according to OECD 301 F or at least 20% when measured according to OECD 302 C (MITI-II test). This corresponds to the OECD 302 C limit set out in the Revised Introduction to the OECD Guidelines for testing of Chemicals, section 3, Part 1, dated 23 March 2006. Paper that exhibits a value of 60% or more in the OECD 301 F test is also referred to in the context of this specification as "rapidly biodegradable."

[0079] In one embodiment of the coated paper according to the first or second aspect of the present invention, the coated paper is "readily biodegradable" according to OECD 301.

[0080] Additionally, coated paper according to the first or second aspect of the present invention is recyclable. "Paper recycling" refers to the process of disintegrating and reprocessing waste paper, used paperboard, and cardboard in an industrial facility to remanufacture new paper or paperboard. In some cases, waste paper is first used to produce intermediate materials such as "recycled paper pulp," which is then used to manufacture new paper. "Deinking," the removal of printing ink from printed waste paper, is a key step in paper recycling. The INGEDE Method 11, for example, is used to assess recyclability. The coated paper of the present invention exhibits a deinkability score of greater than 50 according to the INGEDE Method 11. Preferably, a deinkability score of greater than 70 is obtained.

[0081] By using barrier layer components according to the first or second aspect, the coated paper is suitable for direct or indirect food contact, and in particular has properties that make it suitable for approval according to the guidelines of the European Food Safety Authority (EFSA).

[0082] Any type of paper (paperboard, cardboard, or regular paper) can be used as the base paper for the coated paper according to the first or second aspect. Paper made from pulp derived from hardwood or softwood is particularly preferred. For food packaging applications, low basis weight paper is often required for flexibility and resource conservation. Applying the coating layer of the present invention to such low basis weight paper can significantly improve barrier performance.

[0083] In one embodiment of the coated paper according to the first or second aspect, the basis weight (weight per area) of the base paper is 150 g / m 2 For example, less than 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 , 30g / m 2 In one embodiment, the basis weight is 100 g / m 2 in another embodiment less than 80 g / m 2 and in yet another embodiment, 50 to 80 g / m 2 It may be in the range of.

[0084] The coated paper according to the first or second aspect may include other layers in addition to the barrier layer, and in some embodiments, the coated paper may further comprise an additional layer that is at least one of a coating composition, an ink, a sealing medium, and an adhesive.

[0085] Such additional layers may be located on top of the barrier layer, between the base paper and the barrier layer, or on the opposite side of the barrier layer (on the back side of the base paper).

[0086] When the barrier layer is directly coated onto the base paper, the barrier layer is in direct contact with the base paper. Indirect coating means that there are one or more layers between the barrier layer and the base paper.

[0087] The additional layer may further reduce the permeability of the coated paper to at least one gas compared to the base paper or may form a barrier to liquids and viscous substances such as fats, oils, hydrocarbons, etc.

[0088] Additionally, additional layers may have the following characteristics: a) Contains at least one hydrophobic polymer (polyacrylate, styrene-butadiene copolymer, polyolefin, etc.). b) Contains at least one hydrophilic polymer (such as a polyvinyl alcohol-based polymer). c) At least one inorganic pigment (platelet pigment such as layer silicate, e.g. kaolin). d) at least one inorganic pigment and a binder. e) Contains amorphous and crystalline regions. f) Containing or consisting of fat-soluble substances, paraffins (especially hard paraffins), waxes (especially microcrystalline waxes), waxes derived from vegetable oils and vegetable fats, waxes derived from animal fats and oils, animal waxes, low molecular weight polyolefins, polyterpenes, and mixtures thereof. g) Reduce or prevent the migration of substances such as those listed in f) above, and in particular prevent or reduce the migration of substances from the lower layer into food, particularly food containing fats and oils. h) Containing or consisting of at least one metal (such as aluminum or gold) or metal oxide (such as aluminum oxide) (e.g., a metallized layer). i) It has hot or cold sealable properties. j) containing at least one adhesive. k) comprises or consists of at least one thermoplastic material (especially a hot-sealable material);

[0089] The base paper of the coated paper according to the first or second aspect may be coated on one or both sides, or may be an uncoated base paper.

[0090] In the case of coated base paper, a coating composition containing a binder is applied to the surface, and the coating composition is based on starch, starch derivatives, calcium carbonate (chalk), kaolin, casein, polymer dispersions, etc., which makes the surface of the base paper denser, smoother, and stronger.

[0091] On the other hand, even uncoated base paper can be surface treated to a maximum of 5 g / m 2 It may also contain pigments.

[0092] In food packaging applications, paper may be required to have a certain level of tear strength or breaking strength. In one embodiment, the tensile strength of the coated paper in the machine direction (paper making direction) is 3.0 to 6.0 kN m -1 A specific example of tensile strength is 3.0 kN m -1 , 3.2 kN m -1 , 3.4 kN m -1 , 3.5 kN m -1 , 3.6 kN m -1 , 3.8 kN m -1 , 4.0 kN m -1 , 4.2 kN m -1 , 4.4 kN m -1 , 4.5 kN m -1 , 4.6 kN m -1 , 4.8 kN m -1 , 5.0 kN m -1 , 5.2 kN m -1 , 5.4 kN m -1 , 5.5 kN m -1 , 5.6 kN m -1 , 5.8 kN m -1 , 6.0 kN m -1 In one embodiment, the strength is 3.5 to 5.5 kN m -1 , and in another embodiment, 4.0 to 5.0 kN m -1 is in the range.

[0093] The barrier properties of the present invention are achieved by using a coating layer as defined in the first aspect.

[0094] Thus, in a third aspect of the present invention, there is provided a composition for use in coating paper, comprising the components defined in the first or second aspect and a solvent. Solvents include water, tetrahydrofuran (THF), ethanol, methanol, ethyl acetate, etc., with water being preferred.

[0095] <Manufacturing method> Although a number of manufacturing processes are possible for producing coated paper according to the present invention, the main barrier properties of the coated paper are particularly achieved by the methods shown in the Examples. Thus, as a fourth aspect of the present invention, there is provided a method for producing coated paper, comprising the following steps: a) preparing a coating composition according to the third aspect by mixing the individual components; b) providing a base paper; c) applying a coating composition to the base paper; d) curing the coating composition to form a coating layer that provides a barrier effect.

[0096] In one embodiment, the coating composition is preferably applied by curtain coating or blade coating methods.

[0097] The method of the present invention can be used to control the properties of the coating layer.

[0098] In addition, the curing temperature, curing time, and curing pressure affect the coating layer homogeneity and barrier performance.

[0099] In one embodiment, the curing temperature is in the range of 20 to 300° C. Examples include 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., and 300° C. In one embodiment, the curing temperature is preferably in the range of 100 to 140° C., and in another embodiment, 110 to 130° C.

[0100] In one embodiment, the curing time is in the range of 10 seconds to 15 minutes. Examples include 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, and 15 minutes. In one embodiment, the curing time is in the range of 1 to 3 minutes.

[0101] In one embodiment, the curing pressure is in the range of 0.2 to 3 bar, and in another embodiment, in the range of 0.9 to 1.1 bar.

[0102] <Package> According to a fifth aspect of the present invention, there is provided a packaging body comprising the coated paper according to the first or second aspect.

[0103] By way of example, the packaging may be food packaging, packaging for the containment of electronic components such as silica packs, packaging for medical products such as rapid test kits, packaging for cleaning agents in powder or tablet form, etc.

[0104] The packages of the present invention may also be used to package dried foods, refrigerated foods that require further cooking, large portion-sized foods, or single portion-sized foods sold together.

[0105] Examples of packaging forms include standing pouch packaging, pillow (tube bag) packaging, wrapping paper, etc. In one embodiment, the packaging body is a pillow-shaped bag. [Example]

[0106] Example 1 - Raw materials, coating composition and preparation of barrier paper

[0107] <Support> In all examples, the substrate was CCK paper (Clay Coated Kraft: clay-coated paper, coating weight 5 g / m 2 The CCK paper was made from hardwood and softwood pulp and had a total basis weight of 63 g / m². 2 is.

[0108] <Preparing raw materials> All waxes and carboxylic acid derivatives were prepared as aqueous dispersions, stabilized by the addition of polyvinyl alcohol (approximately 10 wt%, viscosity 69 mPa·s (4% aqueous solution), degree of hydrolysis 86.7–88.7 mol%).

[0109] The solids (dry matter) concentration (TG) of each dispersion was adjusted by adjusting the amount of water added as follows: Candelilla wax (44%), carnauba wax (40%), stearic acid (25%), palmitic acid (25%), stearamide (25%).

[0110] Shellac (Swanlac® ASL 10, deparaffinized and decolorized) was prepared by dissolving in aqueous ammonia (TG=25%). Methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) were used in powder form. Polyethylene glycol (PEG) 400 was used without any pretreatment.

[0111] <Production of Coating Composition> The solids content of the coating compositions ranged from approximately 23 to 40% depending on the system. After mixing the dispersions, no additional water was added. After mixing, the mixture was passed through an 80 μm mesh sieve and degassed using a Hauschild SpeedMixer at 30 mbar and 800 rpm for 4 minutes.

[0112] <Coating on base paper> The coating composition (approximately 3 to 5 mL for DIN A4 size) was applied to the CCK-coated surface of DIN A3 size paper at room temperature using a film applicator (bar coater manufactured by Erichsen). 2 The bar gauge is selected so that the coating weight is the weight of the film after drying.

[0113] After coating, the paper was immediately attached to cardboard with a magnet to prevent curling, and dried in a circulating oven (Memmert, settings: exhaust 50%, fan 50%) at 110°C until the barrier layer was completely formed.

[0114] Example 2 - Barrier performance of single component reference coating composition

[0115] First, a coating composition consisting of a single component (carboxylic acid component [fatty acid and its derivatives], wax, and natural resin [shellac]) was prepared and its water vapor barrier properties were evaluated.

[0116] The following compositions were prepared according to the procedure described in Example 1: Shellac: Dissolved in ethanol (25% by weight) Shellac: Glacial acetic acid solution (25% by weight) Shellac: Dissolved in 5% ammonium carbonate aqueous solution (25% by weight) Candelilla wax dispersion (26% by weight) Carnauba wax dispersion (26% by weight) Palmitic acid dispersion (25% by weight) Stearic acid dispersion (25% by weight) Stearic acid amide dispersion (25% by weight)

[0117] These coating compositions were applied to pretreated base paper in the same manner as in Example 1. The coating amount was 10 g / m 2 The drying time was about 1 to 1.5 minutes at about 110°C.

[0118] The water vapor transmission rate (WVTR) was measured in accordance with DIN 53122-1 / DIN 53122 A (related standards: ISO 2528:1995, ASTM E 96) under "tropical conditions" of 38°C and 90% relative humidity (RH). The results are shown in Table 1.

[0119] [Table 1]

[0120] Shellac-only barrier paper has a WVTR of 200 g / m 2 The water vapor barrier performance exceeded 1000mV / day, indicating low values. On the other hand, barrier papers made from natural waxes and fatty acids / fatty acid derivatives showed significantly reduced WVTR. However, particularly when fatty acids were used, there was a tendency for the coating film to vary in uniformity, resulting in greater variation in WVTR within the surface of the barrier paper.

[0121] Example 3 - Characterization of two-component coating compositions of the present invention

[0122] <3.1 Two-component coating composition consisting of shellac and candelilla wax> [3.1.1. Coating with Raquel] In this test series, the water vapor barrier performance of a two-component coating composition consisting of shellac and candelilla wax was evaluated.

[0123] Following the procedure of Example 1, PVA (viscosity 6-9 mPa·s (4% aqueous solution), degree of hydrolysis 86.7-88.7 mol%) was added to shellac and candelilla wax to prepare dispersions with shellac to candelilla wax ratios of 0:100, 20:80, 40:60, 60:40, 80:20, and 100:0.

[0124] These coating compositions were applied to the base paper in the same manner as in Example 1. The coating amount was 10 g / m 2 is.

[0125] Furthermore, for compositions with a candelilla wax dispersion:shellac ratio of 20:80, the coating amount is 5 to 30 g / m 2 The coating was carried out while changing the temperature within the range of .

[0126] In this example, drying is always performed at a temperature range of 90 to 120°C, and the time is predetermined. The drying time is set as short as possible to ensure complete formation of the barrier layer (a state in which a uniform gloss appears), while avoiding excessive heat treatment (tempering). Tempering refers to the process of uniformly heating and maintaining a material at a temperature below its melting point for several minutes to several hours. Prolonged drying can cause the material to penetrate further into the paper, potentially impairing its barrier performance. In this example, drying was performed at approximately 110°C for 1 to 1.5 minutes.

[0127] The water vapor transmission rate (WVTR) was measured at 38°C and 90% RH (tropical conditions) using the Bechermethod (cup method) in accordance with DIN 53122-1 / DIN 53122 A (related to ISO 2528:1995, ASTM E 96). The results are shown in Figures 1 and 2.

[0128] By mixing shellac and wax dispersion, the film-forming property and drying characteristics when the coating composition was applied to the base paper were improved. Furthermore, at a coating weight of 10 g / m 2 The WVTR was improved compared to single-component coatings. The WVTR was lowest when the shellac to candelilla wax ratio was 1:4 (i.e., 20:80). Also, by blending the wax dispersion with shellac, it is possible to reduce the amount of PVA that is necessarily added during processing.

[0129] The coating weight also had a significant effect on WVTR, with a coating weight of 5 g / m 2 When the WVTR is reduced to about 40 g / m 2 day to 80g / m 2 On the other hand, increasing the coating weight reduces the WVTR to almost 0 g / m 2 It can be reduced to nearly 15g / m 2 It was observed that WVTR tended to be minimized at a coating weight of about 100%.

[0130] [3.1.2. Coating by curtain coating] By adding known process additives (thickeners, surfactants, etc.), the composition of the present invention, consisting of 80% candelilla wax dispersion and 20% shellac solution, can be applied and dried by curtain coating. The line speed of the coater is at least 200 m / min. The WVTR of the resulting paper is 27.4 ± 2.0 g / m. 2 ·day.

[0131] [3.1.3. Storage stability] The storage stability of the coated paper having a coating film consisting of candelilla wax dispersion and shellac prepared in the previous section 3.1.2 was tested.

[0132] These papers were stored at 23°C and 50% relative humidity for 10, 75, 100, 150, and 200 days, after which their water vapor barrier performance was evaluated. The results are shown in Figure 3.

[0133] <3.2 Two-component coating composition consisting of shellac and stearic acid> This test series evaluated the water vapor barrier performance of a two-component coating composition combining shellac and stearic acid.

[0134] Coating compositions with varying ratios of shellac and stearic acid were prepared according to the procedure of Example 1. The specific compositions are shown in Table 2.

[0135] In preparing the coated paper, the coating composition was applied to the base paper in the same manner as in Example 1, and the dry film weight was 10 g / m 2 The drying was carried out at about 90°C for 2 to 2.5 minutes.

[0136] The WVTR measurements were carried out in accordance with DIN 53122-1 / DIN 53122 A (related to ISO 2528:1995, ASTM E 96) at 38°C and 90% RH. The results are shown in Table 2.

[0137] [Table 2]

[0138] It was confirmed that the two-component coating layer consisting of shellac and stearic acid has improved film-forming and drying properties compared to the single-component coating layer. 2The WVTR for this coating is improved compared to the single-component coating. It is speculated that the addition of shellac inhibits the crystallization of stearic acid on the surface, thereby improving water vapor barrier performance and promoting uniformity of the coating. By varying the composition of the shellac and stearic acid dispersion, the WVTR was minimized when the shellac:stearic acid dispersion ratio was approximately 1:3 (25:75). Furthermore, blending stearic acid with shellac also reduces the amount of PVA required for processing.

[0139] <3.3 Two-component coating composition consisting of shellac and stearic acid amide>

[0140] In this test series, two-component coating compositions consisting of shellac and stearic acid amide were prepared and their water vapor barrier performance (WVTR) was evaluated.

[0141] Coating compositions were prepared by adding PVA (viscosity: 6-9 mPa·s (4% aqueous solution), degree of hydrolysis: 86.7-88.7 mol%) to coating compositions containing varying ratios of shellac and stearic acid amide according to the method of Example 1. The weight ratios of shellac to stearic acid amide dispersion (25% solids) were 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100.

[0142] To prepare coated paper, these coating compositions were applied to base paper in the same manner as in Example 1. The coating amount was 10 g / m 2 It was decided.

[0143] Furthermore, for compositions with a 50:50 ratio of shellac and stearic acid amide dispersion, the coating amount is 1 to 20 g / m 2 was varied within the range of

[0144] In this example, drying was carried out for a specified time at a constant temperature of 130°C. The drying time was set as short as possible until the barrier layer was completely formed (until a uniform gloss was achieved). If drying was carried out for a long time, impregnation into the paper would progress, reducing the barrier performance of the coated paper. In this example, the drying temperature was 130°C and the drying time was approximately 2 to 3 minutes.

[0145] The water vapor transmission rate (WVTR) was measured using the Bechermethode (cup method) in accordance with DIN 53122-1 / DIN 53122 A (related standards: ISO 2528:1995, ASTM E 96) under tropical conditions of 38°C and 90% relative humidity (RH). The results are shown in Tables 3 and 4.

[0146] [Table 3]

[0147] By mixing shellac with stearic acid amide dispersion, film-forming and drying properties are improved when coating on base paper. 2 The two-component coating prepared by this method showed improved WVTR compared to single-component coatings. By varying the ratio of shellac to stearamide, the WVTR was minimized at a shellac:stearamide ratio of 1:1 (50:50). Furthermore, combining stearamide dispersion with shellac reduced the amount of PVA required for processing.

[0148] [Table 4]

[0149] The coating weight has a significant effect on WVTR. 2 When reduced to less than 55g / m, the WVTR is approximately 55g / m 2 day to 90g / m 2 On the other hand, increasing the coating weight increased the WVTR to 40 g / m 2 In this example, the load can be reduced to approximately 20 g / m2 With a coating weight of 36g / m, the WVTR is 36g / m 2 The number of days was reduced to 100.

[0150] Example 4 - Evaluation of a three-component coating composition according to the present invention

[0151] <4.1 Three-component system of candelilla wax, carnauba wax, and shellac>

[0152] In this test series, a three-component coating composition consisting of candelilla wax, carnauba wax, and shellac was prepared and its water vapor barrier performance was evaluated.

[0153] Following the procedure of Example 1, coating compositions were prepared by mixing candelilla wax, carnauba wax, shellac, and PVA (viscosity 6-9 mPa s (4% aqueous solution), degree of hydrolysis 86.7-88.7 mol%) in various proportions. Table 5 shows the compositions.

[0154] This composition was applied to a base paper in the same manner as in Example 1, with a coating weight of 10 g / m 2 Drying was carried out at approximately 110°C for 1 to 2 minutes.

[0155] The WVTR was measured in accordance with DIN 53122-1 / DIN 53122 A (related to ISO 2528:1995, ASTM E 96) under tropical conditions of 38°C and 90% RH. The results are shown in Table 5.

[0156] [Table 5]

[0157] The three-component barrier layer, consisting of shellac, candelilla wax, and carnauba wax, has a coating weight of 10 g / m 2 When WVTR is 20g / m 2 In addition, the three-component coating showed oil resistance as confirmed by the palm kernel fat test (EN ISO 53116).

[0158] <4.2 Three-component system of candelilla wax, stearic acid, and shellac>

[0159] This test series evaluated the water vapor barrier properties of a three-component coating composition consisting of candelilla wax, stearic acid, and shellac.

[0160] Coating compositions were prepared by varying the mixing ratio of candelilla wax, stearic acid, and shellac according to the procedure of Example 1. The mixing ratios are shown in Tables 6 and 7.

[0161] Coated paper was prepared by coating these compositions on base paper in the same manner as in Example 1, with a uniform coating amount of 10 g / m 2 Drying was carried out at 120°C for about 1 to 2 minutes.

[0162] The WVTR was measured in accordance with DIN 53122-1 / DIN 53122 A (related to ISO 2528:1995, ASTM E 96) at 38°C and 90% RH. The results are shown in Tables 6 and 7.

[0163] [Table 6]

[0164] [Table 7]

[0165] A three-component coating layer consisting of shellac, candelilla wax, and stearic acid was applied at a coating weight of 10 g / m 2 The barrier paper formed with this also has a WVTR of 20 g / m 2 In particular, compositions containing high amounts of shellac or stearic acid showed good adhesion when overcoated with water-based barriers (oxygen barriers, sealants, etc.). Furthermore, although shellac alone has a high WVTR and low water vapor barrier properties, in the case of a three-component system, even compositions containing up to 50% shellac showed a WVTR of 20 g / m². 2It was shown that a WVTR of less than 1 day could be achieved.

[0166] Example 5 - Evaluation of inventive coating compositions containing film-forming agents

[0167] 5.1 Changes in film-forming agent composition

[0168] This test series evaluated the effect of film formers in stearic acid based coating compositions.

[0169] A coating composition was prepared using the basic formulation shown in Table 8 by the method described in Example 1.

[0170] [Table 8]

[0171] In this example, coating compositions were prepared using different types of MC and HPMC. The specific differences are as follows: ·HPMC1: (2% aqueous solution, viscosity 3mPa·s, DS=1.9, MS=0.23) ·HPMC2: (2% aqueous solution, viscosity 50mPa·s, DS=1.9, MS=0.23) HPMC3: (2% aqueous solution, viscosity 50 mPa·s, DS=1.8, MS=0.13) MC1: (2% aqueous solution, viscosity 4 mPa·s, DS=1.8) MC2: (2% aqueous solution, viscosity 25 mPa·s, DS=1.8) MC3: (2% aqueous solution, viscosity 400 mPa·s, DS=1.8)

[0172] The coated paper was prepared in accordance with Example 1, with a coating weight of 10 g / m 2 The drying was carried out at 110°C for about 1 to 1.5 minutes.

[0173] The WVTR was measured at 38°C and 90% RH in accordance with DIN 53122-1 / DIN 53122 A (corresponding to ISO 2528:1995, ASTM E 96). The results are shown in Table 9.

[0174] [Table 9]

[0175] These results confirm that the higher the viscosity of the MC and HPMC used, the lower the WVTR of the resulting barrier paper.

[0176] 5.2 Changes in fatty acid composition

[0177] Using the same method as in Section 5.1 above, palmitic acid or a mixture of palmitic acid and stearic acid was used as the fatty acid component instead of stearic acid.

[0178] [Table 10]

[0179] For other preferred embodiments of the device of the invention, reference is made to the general description of this specification and the appended claims to avoid repetition.

[0180] Finally, it is expressly stated that the embodiments described as specific examples in this specification are intended merely to illustrate the claimed technical ideas and are not intended to limit the scope thereof.

Claims

1. A coated paper comprising a base paper and at least one coating layer coated directly or indirectly on the base paper, The coating layer is 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, gummilack, rosin, sandarac, mastic, coniferous resin, damar, gum arabic, and elemi; Including, and a coated paper having reduced permeability to at least one of the coated papers compared to the base paper.

2. A coated paper comprising a base paper and at least one coating layer coated directly or indirectly on the base paper, The coating layer is 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 Including, Furthermore, the coated paper has reduced permeability to at least one type of gas compared to the base paper.

3. 3. The coated paper of claim 1 or 2, wherein the coating further comprises a polymeric stabilizer.

4. 10. The coated paper according to claim 9, which has a lower permeability to at least one type of gas than a coated paper having the same base paper and a coating layer made of natural wax or saturated fatty acid and a coating layer made of natural resin, respectively.

5. The coating amount of the coating layer is 10±1 g / m ２ When the water vapor transmission rate (WVTR) measured at a temperature of 38°C and a humidity of more than 90% is 50 g m －２ ・day －１ Preferably 20 g m or less －２ ・day －１ 10. The coated paper of claim 1, wherein:

6. 10. Coated paper according to any one of the preceding claims, wherein the carboxylic acid component is selected from a fatty acid, a hydroxy fatty acid or a dicarboxylic acid, or an ester, amide or salt thereof.

7. 7. 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 zero or one double bond, more preferably selected from palmitic acid, margaric acid and stearic acid, and in particular the carboxylic acid component is stearic acid or an amide thereof.

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

9. 9. The coated paper of claim 2, wherein the polymer 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, α-isodecyl-ω-hydroxypoly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, 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, α-isodecyl-ω-hydroxypoly(oxy-1,2-ethanediyl), styrene-butadiene latex, styrene-acrylate polymer, acrylic copolymer, and mixtures thereof.

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

11. 10. Coated paper according to any one of claims 2 to 9, wherein the coating layer comprises natural waxes, natural resins, and optionally polymeric stabilizers, and satisfies: a) the proportion of natural waxes is in the range of 40 to 95% by weight, preferably 60 to 90% by weight, more preferably 50 to 85% by weight, and most preferably 60 to 80% by weight, relative to the total weight of the coating layer; b) the proportion of natural resin is in the range of 5 to 60% by weight, preferably 10 to 40% by weight, more preferably 20 to 40% by weight, relative to the total weight of the coating layer; and / or b) The proportion of polymeric stabilizer is less than 20% by weight, preferably in the range of 1 to 15% by weight, more preferably 2 to 10% by weight, relative to the total weight of the coating layer.

12. 12. The coated paper according to claim 1, wherein the coating layer contains, as a film-forming agent, at least one cellulose derivative 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), and hydroxyethyl methyl cellulose (HEMC), and the coating layer preferably contains, as film-forming agents, two types of cellulose derivatives, the film-forming agents being MC and CMC.

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

14. The coating layer a) at least two natural waxes, or one natural wax and at least one saturated fatty acid; b) at least one natural resin; The coated paper of any one of claims 1 and 3 to 9, comprising:

15. the coating layer comprises two natural waxes, one natural resin, and optionally a polymeric stabilizer; a) the proportion of natural waxes is in the range of 15 to 60% by weight, preferably 25 to 55% by weight, more preferably 35 to 55% by weight, and most preferably 40 to 50% by weight, relative to the total weight of the coating layer; b) the proportion of natural resin is in the range of 30 to 85% by weight, preferably 40 to 70% by weight, more preferably 45 to 60% by weight, relative to the total weight of the coating layer; and / or b) the proportion of polymeric stabilizer is less than 20% by weight, preferably in the range of 1 to 15% by weight, more preferably in the range of 2 to 10% by weight, relative to the total weight of the coating layer; The coated paper of claim 14.

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

17. The coating amount of the coating layer is 2 to 30 g / m ２ , preferably 5 to 20 g / m ２ , particularly 8 to 15 g / m ２ 10. The coated paper of claim 9, wherein the thickness of the coated paper is in the range of 100 μm to 100 μm.

18. 10. The coated paper of any one of the preceding claims, wherein the coated paper has at least one of the following properties: The coated paper is biodegradable, in particular readily biodegradable according to OECD 301; The coated paper is recyclable. The coated paper can be approved for direct or indirect contact with food, in particular according to the guidelines of the European Food Safety Authority.

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

20. 1. A method for producing a coated paper having a base paper and a coating layer, the method comprising the steps of: a) preparing the coating composition of claim 19 by melt dispersing, high pressure dispersing, or spray drying the components followed by mechanical dispersion; b) providing a base paper; c) applying the coating material to a base paper, preferably by curtain coating or blade coating; and d) A step of curing the coating material to form a coating layer.

21. A packaging body comprising the coated paper according to any one of claims 1 to 18.

22. 22. The packaging of claim 21 for use in food packaging, for use as inserts for electronic components such as silica gel packs, for use in medical products such as rapid tests, for use in cleaning agents and detergents, in particular for cleaning agents and detergents in powder or tablet form.

Images