Compostable packaging material

Abstract

The present disclosure relates to a coated paper. The coated paper includes a cellulosic layer and at least two coating layers on one side of the paper. The first coating applied to the paper is a barrier coating that can be made from a plant-or animal-derived component, which is preferably water-soluble or water-dispersible, more preferably water-soluble. In another aspect, the second coating may be a heat sealable coating. The coated paper is particularly suitable for use in the construction of packages.

Description

Background Art

[0001] Most of the flexible packaging materials used in the market for producing non-rigid packaging are made of fossil-based polymers. These materials include, for example, multi-layer films containing polyethylene terephthalate polymers and / or polyethylene polymers. Although these films can provide excellent barrier properties and are heat-sealable, these films are not sustainable and are not environmentally friendly. These films and the packaging made from these films contain disposable plastics that are used only once and then discarded. Although some disposable plastics may eventually enter the recycling process, most of these materials will ultimately be landfilled and degrade at a very slow rate.

[0002] In view of the above, those skilled in the art have attempted to replace fossil-based plastic films with paper materials. For example, paper products are formed from sustainable resources and are biodegradable and compostable. However, when used as a packaging material, paper has various drawbacks and deficiencies. For example, paper may be prone to tearing, is not waterproof, and does not have heat-sealing properties.

[0003] The patent WO 2022 / 243445 entitled "Coated Paper for Use as a Packaging Material" discloses a heat-sealable coated paper that includes a cellulose layer and a coating on at least one side of the cellulose layer, and this patent is incorporated herein by reference. The coating contains wax and a polymer selected from polyester, polysaccharide, polysaccharide ester, polysaccharide ether, or polysaccharide ether ester. Although WO '445 represents a great advancement in the art, further improvements are still needed. In particular, there is a need for a heat-sealable coated paper with enhanced barrier properties. For example, there is a need for a coated paper with a lower moisture permeability and a lower oxygen permeability. Summary of the Invention

[0004] An object of the present invention is to provide a coated paper that is very suitable for use as a packaging material, which not only has excellent barrier properties such as low moisture permeability and low oxygen permeability, but also has excellent heat-sealable properties. In one aspect, the coated paper can be made completely biodegradable and / or compostable, preferably home-compostable. For example, the coated paper can be manufactured to pass the EN 13432:2001 compostability test. In addition to being sustainable and environmentally friendly, the coated paper of the present disclosure also has excellent mechanical properties, is easy to process, and can have excellent barrier properties.

[0005] In one aspect, the coated paper includes a cellulose layer having a first side and an opposite second side. A barrier coating is applied to the first side of the cellulose layer. The barrier coating contains a component derived from a plant or an animal, which is preferably water-soluble or water-dispersible, more preferably water-soluble. A heat-sealable coating is applied on the barrier coating. The heat-sealable coating contains wax.

[0006] The combination of the barrier coating and the heat-sealable coating not only provides heat-sealable properties to the coated paper, but also provides excellent barrier properties. For example, the coated paper can exhibit a moisture vapor transmission rate (MVTR) of less than about 10 g / m 2 / 24 h, preferably less than about 9 g / m 2 / 24 h, more preferably less than about 8 g / m 2 / 24 h, even more preferably less than about 7 g / m 2 / 24 h, even more preferably less than about 6 g / m 2 / 24 h, even more preferably less than about 5 g / m 2 / 24 h, even more preferably less than about 4 g / m 2 / 24 h, even more preferably less than about 3 g / m 2 / 24 h, even more preferably less than about 2 g / m 2 / 24 h, most preferably less than about 1 g / m 2 / 24 h. Coated paper 10 can also exhibit excellent oxygen barrier properties. For example, the coated paper can exhibit an oxygen transmission rate (OTR) of less than about 2 cm 3 / m 2 / 24 h, preferably less than about 1.75 cm 3 / m 2 / 24 h, more preferably less than about 1.5 cm 3 / m 2 / 24 h, even more preferably less than about 1.25 cm 3 / m 2 / 24 h, even more preferably less than about 1 cm 3 / m 2 / 24 h, even more preferably less than about 0.75 cm 3 / m 2 / 24 h, even more preferably less than about 0.5 cm 3 / m 2 / 24 h, most preferably less than about 0.25 cm 3 / m 2 / 24 h.

[0007] The barrier coating applied to the cellulose layer of the present disclosure significantly improves the barrier properties, specifically providing a low oxygen transmission rate, while the heat-sealable coating not only provides heat-sealable properties but also protects the barrier coating from degradation. As described above, the barrier coating comprises a component derived from a plant or an animal, which is optionally water-soluble or water-dispersible and may also be amorphous. In one aspect, the component derived from a plant or an animal can be a milk protein.

[0008] A barrier coating can be applied to the cellulose layer to have a basis weight of at least about 2 g / m 2 , for example, at least about 4 g / m 2 , for example, at least about 6 g / m 2 , for example, at least about 8 g / m 2 , for example, at least about 10 g / m 2 , for example, at least about 12 g / m 2 , for example, at least about 14 g / m 2 , and less than about 25 g / m 2 , for example, less than about 20 g / m 2 , for example, less than about 18 g / m 2 . In addition to containing components derived from plants or animals, the barrier coating can also contain various other components, including polymers and / or fillers. For example, in one aspect, the barrier coating can also contain a polyvinyl alcohol polymer. In another embodiment, the barrier coating can contain cellulose particles, such as nanocrystalline cellulose.

[0009] In one aspect, the wax contained in the heat-sealable coating can be a plant wax. For example, the plant wax can be candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, pea wax, coconut wax, and palm tree wax, or a combination thereof, preferably soybean wax. In one aspect, the heat-sealable coating can also contain a polymer. The polymer can be a polyester, polysaccharide, polysaccharide ester, polysaccharide ether, polysaccharide ether ester, latex polymer, or a combination thereof. In one aspect, the polymer can be a thermoplastic starch. The heat-sealable coating can be applied to the cellulose layer to have a basis weight equal to or greater than about 1 g / m 2 , for example, equal to or greater than about 2 g / m 2 , for example, equal to or greater than about 3 g / m 2 , for example, equal to or greater than about 4 g / m 2 , for example, equal to or greater than about 5 g / m 2 , and generally equal to or less than about 25 g / m 2 , for example, equal to or less than about 20 g / m 2 , for example, equal to or less than about 18 g / m 2 , for example, equal to or less than about 15 g / m 2 , for example, equal to or less than about 12 g / m 2 .

[0010] In one embodiment, the coated paper includes only two layers of coatings, namely, a barrier coating and a heat-sealable coating. Alternatively, a coating for receiving printing can be applied to the second side of the cellulose layer opposite to the barrier coating and the heat-sealable coating. In one aspect, the coated paper is configured such that the product does not contain petroleum-based synthetic polymers, and / or there is no adhesive layer between the barrier coating and the first side of the cellulose layer or between the barrier coating and the heat-sealable coating.

[0011] The cellulose layer can be made of any suitable cellulose fibers. For example, the cellulose layer can be made of wood pulp fibers such as softwood fibers. The cellulose layer can also be made of bast fibers, for example, made of bast pulp fibers. The bast fibers can be hemp fibers or flax fibers, etc. The cellulose layer can also contain hardwood fibers. In one aspect, the cellulose layer can contain only wood pulp fibers or a combination of wood pulp fibers and bast fibers. Generally, the cellulose layer can have a basis weight of about 20 g / m 2 to about 200 g / m 2 , including all values therebetween in 1 g / m 2 increments. For example, the cellulose layer can have a basis weight of about 20 g / m 2 to about 100 g / m 2 , such as about 30 g / m 2 to about 70 g / m 2 . On the other hand, the coated paper product can have a total basis weight of about 25 g / m 2 to about 250 g / m 2 , including all values therebetween in 1 g / m 2 increments. For example, the coated paper product can have a basis weight of about 25 g / m 2 to about 125 g / m 2 , such as about 35 g / m 2 to about 90 g / m 2 , such as about 40 g / m 2 to about 80 g / m 2 .

[0012] The present disclosure also relates to a package formed from the above-mentioned coated paper. In one embodiment, the package is capable of defining a hollow outer shell or an internal volume formed between two layers of coated paper. The coated paper can be heat-sealed together along the edges of the product.

[0013] Other features and aspects of the present disclosure will be discussed in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The complete and enabling disclosure of the present disclosure will be set forth more particularly in the remainder of the specification (including the reference drawings), in which:

[0015] Figure 1 is a cross-sectional view of an embodiment of a coated paper product manufactured in accordance with the present disclosure;

[0016] Figure 2 is a perspective view of an embodiment of a package manufactured in accordance with the present disclosure.

[0017] Reference numerals repeated in this specification and the drawings represent the same or similar features or elements in the present invention.

[0018] Definition

[0019] As used herein, "coating" refers to a film formed on the surface of a cellulose layer. The coating can be a continuous coating or a discontinuous coating. The coating can cover the entire surface of the cellulose layer. In one aspect, after applying one or more coatings to the cellulose layer, no fibers are exposed in the cellulose layer.

[0020] As used herein, "moisture vapor transmission rate" (MVTR) is measured in accordance with DIN EN ISO 15106-3:2005-01 at a relative humidity of 50% and a temperature of 23°C.

[0021] As used herein, "oxygen transmission rate" (OTR) is measured in accordance with DIN EN ISO test 15105-2:2003 at a relative humidity of 50% and a temperature of 23°C.

[0022] As used herein, the term "biomass" is broadly understood to cover all kinds of plant and animal materials and materials derived from these materials. As understood herein, "components derived from plants or animals" can be obtained from biomass. As used herein, biomass and components derived from plants or animals do not include petroleum or petroleum-derived products.

[0023] The biomass used in the present invention can include high molecular compounds, examples of which are lignin and polysaccharides such as starch, cellulose, hemicellulose, commonly also referred to as glycans, glycogen, and alginate.

[0024] It should be understood that certain types of biomass can include materials derived from plants and materials derived from animals. By way of example, manure (faeces), urine and sewage sludge may be mentioned. Although the biomass used in the present invention is preferably plant biomass, i.e., the biomass of plants or biomass derived from plants, there may be certain animal biomass therein (i.e., the biomass of animals or biomass derived from animals). For example, the biomass can contain up to 30% of animal biomass. According to a preferred embodiment, the biomass used in the present disclosure is preferably plant biomass, which contains more than 70 weight percent, most preferably more than 90 weight percent of polysaccharides and lignin based on the solid content of the biomass.

[0025] For example, the plant biomass can be agricultural plant materials (such as agricultural waste) or all kinds of wood.

[0026] By way of non-limiting example, biomass examples include crops, agricultural food and waste, feed crop residues, wood (such as wood flour, wood waste, waste wood, sawdust, chips and offcuts), straw (including rice straw), grass, leaves, husks and bagasse. In addition, industrial and municipal waste, including waste paper, can also be exemplified.

[0027] As used herein, the term "biomass" preferably also includes monosaccharides such as glucose, ribose, xylose, arabinose, mannose, galactose, fructose, sorbose, fucose and rhamnose, as well as oligosaccharides. Components derived from plants and animals as used herein also include proteins derived from plants or animals, such as milk proteins.

[0028] As used herein, a "biodegradable" component is a component that can be decomposed by living organisms such as bacteria or fungi. Thus, biodegradable components can be decomposed by the action of microorganisms such as bacteria or fungi in the presence or absence of oxygen. In one aspect, the biodegradable component meets the requirements of at least one of the international industrial standards ISO test 17088, EN test 13432:2001, EN test 14995 and / or ASTM test 6400.

[0029] As used herein, the term "compostable" refers to components that can be decomposed into non-toxic natural elements, including industrially and domestically compostable components. For example, compostable components can degrade at a rate consistent with that of similar organic materials. Compostable components degrade when exposed to microorganisms, humidity and / or heat, thereby producing a final compost product. The coated paper manufactured according to the present disclosure can be made to meet the requirements of the European standard EN test 13432:2001 that defines the requirements for industrially compostable components.

[0030] As used herein, the term "water-soluble" means that the component dissolves well in water, preferably at least 50 g / L, more preferably at least 100 g / L, even more preferably at least 150 g / L, and most preferably at least 250 g / L of the component dissolves in water at 25 °C and 1 bar.

[0031] As used herein, the term "water-dispersible" means that, for example, the particles of the component can be dispersed in water by stirring or homogenization, i.e., evenly and finely distributed in water, such that they preferably have a particle size of no more than 1 μm.

[0032] As used herein, the term "pulp" refers to fibers from natural sources such as woody plants and non-woody plants. Woody plants include, for example, deciduous trees and coniferous trees. Non-woody plants include, for example, cotton, flax, reed grass, milkweed, straw, jute, hemp, and bagasse. Pulp fibers can include hardwood fibers, softwood fibers, and mixtures thereof.

[0033] As used herein, the term "average fiber length" refers to the average length of fibers, fiber bundles, and / or fibrous materials determined by measurement using microscopy techniques. A sample of at least 20 randomly selected fibers is separated from a liquid suspension of the fibers. The fibers are mounted on a prepared microscope slide to suspend the fibers in water. A staining dye is added to the suspended fibers to color the cellulose-containing fibers so that they can be distinguished or separated from synthetic fibers. The slide is placed under a Fisher Stereomaster II microscope - S19642 / S19643 series. Using a scale of 0 - 20 mil, 20 fibers in the sample are measured at 20x linear magnification, and the average length, minimum and maximum lengths, and deviation or coefficient of variation are calculated. In some cases, the average fiber length is calculated as the weighted average length of the fibers (such as fibers, fiber bundles, fibrous materials) determined by a device, such as the Kajjaani Fiber Analyzer model FS-200 available from Kajaani Oy Electronics, Kajaani, Finland. The sample is treated with an impregnating liquid according to standard test procedures to ensure the absence of fiber bundles or debris. Each sample is disintegrated in hot water and diluted to an approximately 0.001% suspension. When tested using the standard Kajjaani fiber analysis test procedure, individual test samples of approximately 50 to 100 ml portions are taken from the diluted suspension. The weighted average fiber length can be an arithmetic mean, length-weighted mean, or weight-weighted mean, and can be represented by the following formula:

[0034]

[0035] Where:

[0036] k = maximum fiber length

[0037] x i = fiber length

[0038] n i = the number of fibers having length x i

[0039] n = the total number of fibers measured. DETAILED DESCRIPTION

[0040] Those of ordinary skill in the art will understand that the discussion herein is merely illustrative of exemplary embodiments and is not intended to limit the broader aspects of the disclosure.

[0041] Generally speaking, the present disclosure relates to a coated paper having excellent barrier and heat-sealing properties. Advantageously, the coated paper of the present disclosure can be entirely composed of sustainable materials. Thus, in one aspect, the coated paper is not only biodegradable and / or compostable, preferably home-compostable, but also very suitable for forming all different types of packaging, especially non-rigid packaging.

[0042] For example, refer to Figure 1 , which shows an embodiment of the coated paper 10 manufactured according to the present disclosure. As shown, the coated paper 10 includes a cellulose layer 12, and at least two different coatings are applied on one side of the cellulose layer 12. In particular, the coated paper 10 includes a barrier coating 14 that can be directly applied to one surface of the cellulose layer 12. A heat-sealable coating 16 is applied on the barrier coating 14 on the same side of the cellulose layer 12.

[0043] As will be described in more detail hereinafter, the barrier coating 14 is formed from components derived from plants or animals, which are preferably water-soluble or water-dispersible, more preferably water-soluble. The barrier coating 14 provides barrier properties to the coated paper 10, especially a low oxygen transmission rate.

[0044] On the other hand, the heat-sealable coating 16 is applied on the barrier coating 14 and protects the barrier coating 14. In particular, the heat-sealable coating 16 can protect the barrier coating 14 from exposure to moisture, which may cause the degradation of the barrier coating 14. In addition, the heat-sealable coating 16 further improves the barrier properties of the entire product, especially provides a low moisture transmission rate. The heat-sealable coating 16 is also heat-sealable, and thus can be used to bond the coated paper to an adjacent coated paper for producing packaging or other articles that require a hollow shell.

[0045] ​The heat-sealable coating 16 can include wax, which is preferably a bio-based wax, and it can exist alone or in combination with other components such as polymers. The polymer combined with the wax can be, for example, a polyester polymer, a polysaccharide, a polysaccharide ester, a polysaccharide ether, a polysaccharide ether ester, a latex polymer, or a combination thereof.

[0046] In one embodiment, the barrier coating 14 and the heat-sealable coating 16 can be applied to one side of the cellulose layer, and a different coating can be applied to the opposite side. For example, a print-receiving coating capable of better receiving prints can be applied to the opposite side of the cellulose layer. For example, the print-receiving coating can be a bio-based polymer layer, which optionally contains filler particles, such as clay particles. In another aspect, the opposite side of the coated paper 10 can include a barrier coating and / or a heat-sealable coating. For example, in one embodiment, each side of the cellulose layer 12 can include a barrier coating 14 disposed adjacent to the surface of the cellulose layer and a heat-sealable coating 16 on each barrier coating.

[0047] As Figure 1 The coated paper 10 shown not only is biodegradable and / or compostable, preferably home-compostable, but also has an excellent balance of properties. For example, the coated paper 10 is flexible and has a Young's modulus well-suited for packaging applications. In addition, the coated paper 10 is strong and tear-resistant. For example, the longitudinal tensile strength of the coated paper can be equal to or greater than about 50 N / 15 mm, preferably equal to or greater than about 55 N / 15 mm, more preferably equal to or greater than about 60 N / 15 mm, still more preferably equal to or greater than about 65 N / 15 mm, still more preferably equal to or greater than about 70 N / 15 mm, most preferably equal to or greater than about 75 N / 15 mm, and generally equal to or less than about 100 N / 15 mm.

[0048] The coated paper 10 can also be configured to have excellent barrier properties. For example, the coated paper 10 can exhibit less than about 10 g / m 2 / 24 hours, preferably less than about 9 g / m 2 / 24 hours, more preferably less than about 8 g / m 2 / 24 hours, still more preferably less than about 7 g / m 2 / 24 hours, still more preferably less than about 6 g / m 2 / 24 hours, still more preferably less than about 5 g / m 2 / 24 hours, still more preferably less than about 4 g / m 2 / 24 hours, still more preferably less than about 3 g / m 2 / 24 hours, still more preferably less than about 2 g / m 2 / 24 hours, most preferably less than about 1 g / m2 / Moisture Vapor Transmission Rate (MVTR) per 24 hours. Coated paper 10 can also exhibit excellent oxygen barrier properties. For example, coated paper 10 can exhibit less than about 2 cm 3 / m 2 / per 24 hours, preferably less than about 1.75 cm 3 / m 2 / per 24 hours, more preferably less than about 1.5 cm 3 / m 2 / per 24 hours, even more preferably less than about 1.25 cm 3 / m 2 / per 24 hours, even more preferably less than about 1 cm 3 / m 2 / per 24 hours, even more preferably less than about 0.75 cm 3 / m 2 / per 24 hours, even more preferably less than about 0.5 cm 3 / m 2 / per 24 hours, most preferably less than about 0.25 cm 3 / m 2 / Oxygen Transmission Rate (OTR) per 24 hours.

[0049] Coated paper 10 can also be defined with an outer surface 18 as shown in Figure 1 , which is a heat-sealable surface. For example, surface 18 can be formulated to be non-sticky at room temperature. Surface 18 or the heat-sealable coating 16 can effect heat sealing at a temperature greater than about 100 °C, such as greater than about 110 °C, such as greater than about 120 °C, such as greater than about 130 °C, such as greater than about 140 °C, such as greater than about 150 °C, such as greater than about 160 °C, such as greater than about 170 °C, such as greater than about 180 °C, and less than about 250 °C, such as less than about 230 °C, such as less than about 220 °C, such as less than about 210 °C, such as less than about 200 °C, such as less than about 190 °C, such as less than about 180 °C. Advantageously, the coating exhibits excellent heat-sealability even at a lower basis weight.

[0050] As shown in Figure 1 , the coated paper 10 can be used to form various different packages using different techniques and processes. For illustrative purposes, reference is made to Figure 2 , which shows a package 50 that can be formed in accordance with the present disclosure. Package 50 can be made of, as shown in Figure 1made from the coated paper 10 shown. The package 50 includes a bottom surface 52, side surfaces 54, and a top surface 56. In this embodiment, the package 50 is formed from two opposing layers of coated paper manufactured in accordance with the present invention. Each side of the package can be made from a single sheet or piece of coated paper, or can be formed by folding the coated paper in an overlapping relationship. The heat-sealable coating 16 on the coated paper 10 can be used to seal the edges of the package 50. For example, as Figure 2 shown, the package 50 includes a sealed edge 60 formed by joining adjacent heat-sealable coatings together. For example, the edge can be formed by applying heat and pressure to the heat-sealable coating 16. However, in other embodiments, various other forms of energy can be used to form the sealed edge. For example, ultrasonic energy can also be used.

[0051] As Figure 2 shown, the package 50 can include a hollow enclosure for containing a number of different items. Since the coated paper is made from sustainable, biodegradable, and / or compostable materials, preferably home-compostable materials, the coated paper is well-suited for contact with food. Thus, in one embodiment, the package 50 can be designed to contain food items, such as snacks. The package can also contain a variety of other items, including hardware, consumer goods, and the like.

[0052] In one embodiment, when filling the package 50 as Figure 2 shown, two layers in the coated paper layer can be joined together and sealed at the edges to create a hollow interior with a certain volume. One or more products can then be loaded into the hollow interior, and the remaining sides of the package can be sealed. To seal the package, the open end of the package can be engaged with a sealing device that applies heat and pressure sufficient to activate the heat-sealable coating and form a thermal bond with the opposing heat-sealable coating.

[0053] As described above, the coated paper can include a barrier coating applied directly to one side of the cellulose layer. According to the present disclosure, the barrier coating is capable of significantly improving the barrier properties of the coated paper, particularly providing a low oxygen transmission rate, while being fully biodegradable and / or compostable, preferably home-compostable.

[0054] In one embodiment, the barrier coating is formed from components derived from plants or animals. The components derived from plants or animals used in the present invention do not include petroleum or petroleum derivatives. The components derived from plants or animals used in the barrier coating are preferably water-soluble or water-dispersible, more preferably water-soluble. Since the components derived from plants or animals are water-soluble or water-dispersible, it is easy to apply the components derived from plants or animals to the cellulose layer and dry. In one aspect, the components derived from plants or animals are amorphous.

[0055] Examples of plant- or animal-derived components for barrier coatings include plant- or animal-derived proteins, such as milk proteins, and polysaccharides, such as alginates, cellulose-based materials or modified starches. Suitable cellulose-based materials are nanofibrillated cellulose (NFC), microfibrillated cellulose (MFC), nanocrystalline cellulose (NCC) or microcrystalline cellulose (MCC). In a preferred embodiment, the plant- or animal-derived component is an animal-derived protein, more preferably a milk protein. The milk protein used for the barrier coating may contain a small amount of residual lactic acid.

[0056] In one embodiment, the barrier coating does not contain saccharide fatty acid esters. As referred to herein, saccharide fatty acid esters include fatty acid esters of all saccharides, including monosaccharides, disaccharides and trisaccharides, including those in which the fatty acid moiety can be saturated, unsaturated or a combination thereof.

[0057] The barrier coating may contain only the above-mentioned plant- or animal-derived components, or may additionally contain various other components. For example, the barrier coating may contain biodegradable and / or compostable polymers, and / or biodegradable and / or compostable fillers. For example, in one aspect, the barrier coating may contain a plant- or animal-derived component combined with a polyvinyl alcohol polymer. The polyvinyl alcohol polymer can be synthesized from polyvinyl acetate and can form different products with different molecular weights and hydrolysis levels. Polyvinyl alcohol particularly suitable for inclusion in the barrier coating may have a high hydrolysis level, such as greater than about 90%, such as greater than about 92%, such as greater than about 94%, such as greater than about 96%, such as greater than about 98%. The hydrolysis level can be less than about 100%, such as less than about 99.5%, such as less than about 99%. The viscosity of polyvinyl alcohol can generally be less than about 50 cP, such as less than about 40 cP, such as less than about 35 cP, and generally greater than about 10 cP, such as greater than about 15 cP, such as greater than about 20 cP, such as greater than about 25 cP. The viscosity of polyvinyl alcohol can be determined according to DIN test 53019, especially according to DIN 53019-1:2008-09. The viscosity can be measured using a Brookfield viscometer.

[0058] In one embodiment, the barrier coating consists of components derived from plants or animals, polyvinyl alcohol polymer, and optionally fillers. The polyvinyl alcohol polymer can be as described above. There are no further specifications for the optionally used fillers. For example, in addition to the following cellulose fillers, the fillers can also be inorganic fillers such as kaolinite (kaolin) and / or talc (soapstone). In this embodiment, the barrier coating preferably consists of 10 wt% to 50 wt%, such as 10 wt% to 20 wt% of components derived from plants or animals (preferably milk protein) and the amount of polyvinyl alcohol polymer to make up 100 wt%, that is, the polyvinyl alcohol polymer constitutes the remainder of the barrier coating.

[0059] The presence of polyvinyl alcohol in the barrier coating is optional. However, when present, based on the dry weight of the barrier coating, the content of polyvinyl alcohol can be equal to or greater than about 3 wt%, such as equal to or greater than about 5 wt%, such as equal to or greater than about 8 wt%, such as equal to or greater than about 10 wt%, such as equal to or greater than about 15 wt%, such as equal to or greater than about 20 wt%, such as equal to or greater than about 25 wt%, such as equal to or greater than about 30 wt%, and its content is usually equal to or less than about 60 wt%, such as equal to or less than about 40 wt%, such as equal to or less than about 20 wt%, such as equal to or less than about 10 wt%. In a preferred embodiment, the barrier coating contains milk protein and polyvinyl alcohol polymer. More preferably, based on the total weight of the barrier coating, the barrier coating contains 50 to 80 wt% of milk protein and 20 to 50 wt% of polyvinyl alcohol polymer, even more preferably 55 to 75 wt% of milk protein and 25 to 45 wt% of polyvinyl alcohol polymer, even more preferably 60 to 70 wt% of milk protein and 30 to 40 wt% of polyvinyl alcohol polymer.

[0060] In addition to containing polymers, the barrier coating may also contain fillers, especially biodegradable and / or compostable fillers. For example, in one embodiment, the barrier coating may contain cellulose fillers such as microcrystalline cellulose or nanocrystalline cellulose. Based on the total weight of the barrier coating, the content of the filler (such as cellulose filler) in the barrier coating is generally equal to or less than about 20% by weight, such as equal to or less than about 15% by weight, such as equal to or less than about 10% by weight, such as equal to or less than about 8% by weight, such as equal to or less than about 5% by weight. Based on the total weight of the barrier coating, the content of the filler (such as cellulose filler) in the barrier coating is generally equal to or greater than about 0.1% by weight, such as equal to or greater than about 1% by weight, such as equal to or greater than about 2% by weight, such as equal to or greater than about 5% by weight.

[0061] The barrier coating is mainly formed on the surface of the cellulose layer, but can also impregnate the cellulose layer. For example, the barrier coating can extend to greater than about 3% of the thickness of the cellulose layer, such as greater than about 5%, such as greater than about 10%, such as greater than about 20%, such as greater than about 30%, such as greater than about 40%, such as greater than about 50%, such as greater than about 60%. The amount of extension of the barrier coating in the cellulose layer can be less than about 70% of the thickness of the cellulose layer, such as less than about 50%, such as less than about 30%, such as less than about 20%, such as less than about 10%. The amount by which the barrier coating penetrates the thickness of the cellulose layer depends on many factors, including the viscosity of the barrier coating during application and the porosity of the cellulose layer.

[0062] The basis weight of the barrier layer can also vary according to specific applications and various factors, including the final application of the coated paper and the basis weight of the cellulose layer. In one aspect, the barrier coating can have a basis weight of about 8 g / m 2 to about 30 g / m 2 , including all values therebetween in 1 g / m 2 increments. For example, the basis weight of the barrier coating can be equal to or greater than about 10 g / m 2 , such as equal to or greater than about 12 g / m 2 , such as equal to or greater than about 14 g / m 2 , such as equal to or greater than about 16 g / m 2 , such as equal to or greater than about 18 g / m 2 , and can be equal to or less than about 25 g / m 2 , such as equal to or less than about 23 g / m 2 , such as equal to or less than about 20 g / m 2 , such as equal to or less than about 18 g / m 2, such as equal to or less than approximately 16 g / m 2 , such as equal to or less than approximately 15 g / m 2 .

[0063] As described above, the barrier coating applied to the cellulose layer is coated with a heat-sealable coating. The heat-sealable coating can be applied directly to the barrier coating and can be included in the coated paper, with no adhesive or bonding layer of any type between the barrier coating and the heat-sealable coating. In fact, the coated paper of the present disclosure can be manufactured without any adhesive layer between any coatings or between the cellulose layer and the coatings.

[0064] The heat-sealable coating generally contains wax. The wax is preferably a bio-based wax, which can be produced from biomass resources, for example. In addition to providing heat-sealable properties, the wax also improves the hydrophobicity, slipperiness, and non-roughness of the coated paper. The heat-sealable coating also enhances surface and barrier properties, especially providing a low moisture transmission rate.

[0065] The wax is preferably a plant wax or an animal wax, more preferably a plant wax.

[0066] Animal waxes generally include wax esters derived from various fatty acids and carboxylic alcohols. Animal waxes can be waxes selected from the group consisting of waxes secreted by insects, spermaceti, and lanolin.

[0067] Insect wax is preferably beeswax. The main component of beeswax is myricyl palmitate, which is an ester of triacontanol and palmitic acid. The melting temperature of beeswax is in the range of 60°C to 65°C. Spermaceti is abundantly present in the head oil of sperm whales. Spermaceti contains cetyl palmitate as the main component. Lanolin is a wax obtained from wool and contains sterol esters.

[0068] Plant waxes are complex mixtures of hydrocarbons, alcohols, aldehydes, ketones, esters, acids, and combinations thereof, which are deposited in the outer layer of epidermal cells. Plant waxes are generally the waterproof components found in the amorphous layer on the outer surface of plants. Plant waxes within the meaning of the present invention also include waxes obtained from vegetable oils or vegetable fats through chemical reactions such as hydrogenation.

[0069] The plant wax is more preferably one or more plant waxes selected from the group consisting of candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, pea wax, coconut wax, and palm tree wax, and even more preferably soybean wax.

[0070] Candelilla wax is mainly obtained from the leaves of the plant Euphorbia antisyphilitica Zuccarini. Unpurified candelilla wax contains approximately 40 - 45 weight percent hydrocarbons, 35 - 45 weight percent waxes, resins and sitosterol esters, 5 - 10 weight percent free waxes and resin acids, 4 - 8 weight percent lactones, and 2 - 8 weight percent free waxes and resin alcohols.

[0071] Carnauba wax is mainly obtained from the carnauba palm tree (Copernicia cerifera Martius), also known as the carnauba wax palm. It is present on both the upper and lower surfaces of the palm leaves. Carnauba wax contains a high proportion of unesterified alcohols, x-hydroxy esters, and hydroxylated cinnamic acid esters. Carnauba wax is one of the hardest plant waxes, having a melting temperature of approximately 80 °C.

[0072] Rice bran wax is another high-melting-point wax found in the husks of rice (Oryza sativa). It is obtained as a by-product of the dewaxing of rice bran oil. The main components of rice bran wax are even-numbered fatty acids and higher alcohol esters. Other components include free fatty acids (palmitic acid), phospholipids, phytosterols, and squalene. The hydrocarbon content of rice bran wax is usually as low as 2 weight percent.

[0073] Sunflower wax is present in the seeds and seed husks of the sunflower (Helianthus annuus). It is obtained by the winterization of sunflower oil. Sunflower wax is a hard, high-melting-point wax mainly composed of long-chain saturated fatty esters.

[0074] Soybean wax can be obtained by the hydrogenation of soybean oil. It is a triglyceride containing a high proportion of stearic acid. It is usually softer than paraffin wax and has a lower melting temperature compared to paraffin wax. Its melting point ranges from approximately 50 °C to approximately 80 °C.

[0075] Sugarcane wax is indigestible and harmless to health. The refined form of sugarcane wax is light yellow. Due to its high melting point of up to 75 °C to 80 °C, it remains stable even when directly exposed to sunlight. Sugarcane wax provides good oil and solvent retention for anionic brightening emulsions.

[0076] The wax used in the present invention is preferably one or more waxes selected from the group consisting of rice bran wax, soybean wax, sugarcane wax, and beeswax, more preferably soybean wax.

[0077] The dropping point of the wax is preferably in the range of 60 °C to 120 °C, more preferably in the range of 60 °C to 110 °C. The dropping point is a characteristic of the wax. To determine the dropping point, the samples can be heated until they change from a solid state to a liquid state. Specifically, the dropping point is the temperature at which the first drop of molten material precipitates from a standard cup with a defined orifice under controlled test conditions in a furnace. In the present invention, the dropping point can be determined according to the procedure described in DIN ISO 2176:1997-05.

[0078] Based on the total weight of the heat-sealable coating, the heat-sealable coating used in the present invention preferably may comprise 10 to 90 weight percent of wax, more preferably 10 to 80 weight percent of wax, still more preferably 10 to 60 weight percent of wax, and most preferably 10 to 40 weight percent of wax. In addition to the wax, the heat-sealable coating may also optionally contain polymers and various other components. The polymers to be used in the heat-sealable coating may be polymers selected from the group consisting of polyesters, polysaccharides, polysaccharide ethers, polysaccharide esters, polysaccharide ether polysaccharide esters, and latex polymers. For example, combining the polymers as described above with wax can improve the heat-sealability of the heat-sealable coating. In addition, the above polymers can completely replace the petroleum-derived heat-sealable polymers used in the past. For example, the above polymers can be produced from biomass. Therefore, the polymers can be sustainable and environmentally friendly, just like bio-based waxes, and exhibit excellent heat-sealability. If home-compostable paper is required, then the heat-sealable coating does not contain latex polymers.

[0079] The polymer is preferably a thermoplastic polymer. If the polymer is a thermoplastic polymer, then the heat-sealability can be further improved.

[0080] The polymer is preferably a thermoplastic polymer having a melting point in the range of 60 °C to 200 °C, more preferably in the range of 100 °C to 180 °C, and most preferably in the range of 110 °C to 180 °C. When the heat-sealable coating of the coated paper of the present disclosure contains a thermoplastic polymer having a melting point in the range of 60 °C to 200 °C, the heat-sealability of the coated paper is improved. When the coating of the coated paper of the present invention contains a thermoplastic polymer in the range of 100 °C to 180 °C, the heat-sealability is further improved.

[0081] In addition, the polymer is preferably a biomass-based polymer, making the coated paper more sustainable and environmentally friendly.

[0082] The polyester may be selected from the group consisting of polyhydroxyalkanoates, polylactic acid, polyglycolic acid, polybutylene succinate, polycaprolactone, polybutylene terephthalate adipate, and polylactic acid-polyethylene glycol.

[0083] Polyhydroxyalkanoates (PHA) are polyesters of hydroxyalkanoic acids. Polyhydroxyalkanoates (PHA) are thermoplastic. They can be homopolyesters or copolyesters, and their properties vary according to their chemical composition (i.e., the hydroxyalkanoic acids contained).

[0084] PHA can be one or more polyesters selected from the group consisting of poly(3-hydroxypropionate), poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanoate), poly(3-hydroxytetradecanoate), poly(3-hydroxypentadecanoate), and poly(3-hydroxyhexadecanoate). PHA can also be a copolyester obtained by copolymerization of two or more hydroxyalkanoic acids. More specifically, PHA copolyesters can be one or more selected from the group of copolyesters consisting of poly(3-hydroxypropionate-co-3-hydroxybutyrate), poly(3-hydroxypropionate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-3-hydroxyhexanoate), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate).

[0085] PHA is preferably one or more polyesters selected from the group consisting of poly(3-hydroxypropionate), poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-3-hydroxyhexanoate), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). PHA is most preferably poly(3-hydroxybutyrate).

[0086] Polybutylene adipate terephthalate is preferably a block copolymer. Poly(lactic acid)-polyethylene glycol is preferably a block copolymer.

[0087] Polysaccharides can be one or more polysaccharides selected from the group consisting of starch, cellulose, arabinoxylan, chitin, and pectin. Polysaccharides are preferably starch or cellulose.

[0088] A plasticizer can be added to the polysaccharide to improve the thermoplasticity of the polysaccharide. Thus, a thermoplastic polysaccharide containing the polysaccharide and the plasticizer is obtained.

[0089] The plasticizer can be one or more compounds selected from the group consisting of polyols, diols, esters of polyols, and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids. The plasticizer is preferably a polyol or a diol, and most preferably one or more compounds selected from glycerol, ethylene glycol, and sorbitol. Glycerol can be vegetable glycerol (VG). Vegetable glycerol is glycerol obtained from vegetable oils such as soybean oil, coconut oil, or palm oil.

[0090] The thermoplastic polysaccharide preferably contains at least one of starch and cellulose. In other words, the thermoplastic polysaccharide is preferably thermoplastic starch, thermoplastic cellulose, or a combination thereof, and more preferably thermoplastic starch. The thermoplastic starch preferably contains one or more plasticizers selected from the group consisting of glycerol, ethylene glycol, and sorbitol.

[0091] In one aspect, the thermoplastic polysaccharide is derived from agricultural waste of corn.

[0092] The polymer used in the heat-sealable coating of the present invention can also be a polysaccharide ether, a polysaccharide ester, or a polysaccharide ether ester.

[0093] The polysaccharide ether is preferably a cellulose ether. The polysaccharide ether is more preferably carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl methyl cellulose, and hydroxypropyl methyl cellulose. The polysaccharide ether is most preferably carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose.

[0094] The polysaccharide ester can be a cellulose ester, such as cellulose acetate.

[0095] The polysaccharide ether ester can be a cellulose ether ester, such as hydroxypropyl methyl cellulose acetate succinate and carboxymethyl cellulose acetate butyrate.

[0096] The polymer is most preferably one or more polymers selected from the group consisting of poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), polylactic acid, poly(lactic acid)-polyethylene glycol block copolymer, polybutylene adipate terephthalate, and thermoplastic starch.

[0097] The heat-sealable coating may comprise one or more of the above polymers, and based on the total weight of the heat-sealable coating, the content of the polymer is generally equal to or greater than about 10 weight percent, preferably equal to or greater than about 20 weight percent, more preferably equal to or greater than about 30 weight percent, still more preferably equal to or greater than about 40 weight percent, and most preferably equal to or greater than about 50 weight percent. Based on the total weight of the heat-sealable coating, the amount of one or more polymers as described above present in the heat-sealable coating is generally equal to or less than about 90 weight percent, preferably equal to or less than about 80 weight percent, more preferably equal to or less than about 70 weight percent, and most preferably equal to or less than about 60 weight percent.

[0098] Based on the total weight of the heat-sealable coating, the heat-sealable coating used in the present invention preferably may comprise 10 to 90 weight percent of wax and 10 to 90 weight percent of polymer, more preferably may comprise 10 to 40 weight percent of wax and 60 to 90 weight percent of polymer. Further, based on the total weight of the heat-sealable coating, the paper coated with the heat-sealable coating comprising 10 to 90 weight percent of wax and 10 to 90 weight percent of polymer combines a paper-like appearance and feel and workability and heat-sealability comparable to a plastic film. Based on the total weight of the heat-sealable coating, when the heat-sealable coating comprises 10 - 40 weight percent of wax and 60 to 90 weight percent of polymer, the heat-sealability of the coated paper is further improved. In addition, based on the total weight of the heat-sealable coating, the coated paper with the heat-sealable coating comprising 10 to 40 weight percent of wax and 60 to 90 weight percent of polymer exhibits improved water vapor barrier properties. In a particularly preferred embodiment, based on the total weight of the heat-sealable coating, the heat-sealable coating comprises 20 to 40 weight percent of wax and 60 to 80 weight percent of polymer. In such a coating, an optimal compromise between water vapor barrier properties and heat-sealability is achieved.

[0099] The heat-sealable coating used in the present invention preferably may comprise soybean wax and a thermoplastic polysaccharide, which is preferably derived from agricultural waste of corn.

[0100] The heat-sealable coating used in the present disclosure may comprise one or more additives. The additive may be at least one compound selected from the group consisting of a rheology modifier and a softening agent.

[0101] The rheology modifier is preferably one or more compounds selected from the group consisting of cellulose, starch, or their derivatives. The rheology modifier is preferably water-soluble or water-dispersible. The rheology modifier is more preferably biomass-based and / or biodegradable. The rheology modifier allows the thickening of the emulsion and improves the emulsion stability. Thus, dripping during the application of the coating can be avoided.

[0102] Using a rheology modifier selected from the group consisting of cellulose, starch, and their derivatives improves the emulsion stability of the heat-sealable coating. At the same time, this rheology modifier is sustainable because it is water-soluble or water-dispersible, biomass-based, and biodegradable. Thus, a sustainable and more environmentally friendly heat-sealable coated paper can be obtained, which is suitable for use as a packaging material and has a desired, preferably paper-like appearance and feel.

[0103] The cellulose can be microcrystalline cellulose, preferably powdered microcrystalline cellulose, such as ARBOCEL produced by JRS.

[0104] The cellulose derivative can be a cellulose ether or a cellulose ether ester. The cellulose ether is preferably carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl methyl cellulose, and hydroxypropyl methyl cellulose. The cellulose ether is more preferably carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose. Hydroxyethyl cellulose can be, for example, Cellosize TM QP-100 produced by Dow. The cellulose ether ester can be hydroxypropyl methyl cellulose acetate succinate and carboxymethyl cellulose acetate butyrate.

[0105] The starch derivative can be, for example, phosphorylated distarch phosphate, preferably waxy maize-based distarch phosphate, such as AGENAJEL 20.350 produced by AGRANA.

[0106] Based on the total weight of the heat-sealable coating, the heat-sealable coating can contain 0 to 3 weight percent, more preferably 0.5 to 2 weight percent of the rheology modifier.

[0107] The heat-sealable coating of the present disclosure can also contain a softening agent. The softening agent can be one or more compounds selected from the group consisting of polyols, diols, esters of polyols, and aliphatic esters of mono-, di-, or polycarboxylic acids. The softening agent is preferably a polyol or a diol, and most preferably one or more compounds selected from glycerol, ethylene glycol, and sorbitol. Glycerin can be vegetable glycerol (VG). Vegetable glycerol is glycerol obtained from vegetable oils such as soybean oil, coconut oil, or palm oil.

[0108] The addition of a softening agent further improves the processability of the coating and the heat sealability of the coated paper.

[0109] Glycerol, ethylene glycol, and sorbitol are water-soluble, biodegradable, and can be produced from biomass. Therefore, a coating containing a softening agent selected from the group consisting of glycerol, ethylene glycol, and sorbitol is sustainable and environmentally friendly.

[0110] Based on the total weight of the heat-sealable coating, the heat-sealable coating preferably contains from 0 to 10 weight percent, more preferably from 2 to 7 weight percent of the softening agent.

[0111] In another aspect, the heat-sealable coating may contain a filler. The filler contained in the heat-sealable coating may be an inorganic filler. For reasons of sustainability and environmental protection, the filler is preferably a filler based on a naturally occurring raw material such as clay. The filler is more preferably a clay mineral, most preferably a layered silicate mineral such as kaolinite. The filler may also be a pigment, more preferably a pigment based on a naturally occurring raw material such as clay, preferably a layered silicate mineral such as kaolinite.

[0112] The pigment may have a steep particle size distribution. In the most preferred embodiment, 90 weight percent of the pigment particles have a particle size of less than 5 μm. This particle size distribution results in an improvement in printing and paper gloss. For example, a high brightness coating pigment such as CAPIM DG slurry from Capim Kaolin can be used. The good rheological properties of the pigment particle slurry having the above particle size distribution allow for high-speed application of the filler, such as high-speed blade coating and metered size press application.

[0113] Based on the total weight of the heat-sealable coating, the heat-sealable coating preferably contains from 0 to 20 weight percent, more preferably from 3 to 15 weight percent of the filler.

[0114] In a preferred embodiment, based on the total weight of the heat-sealable coating, the heat-sealable coating comprises 10 to 90 weight percent of a polymer, 10 to 90 weight percent of a wax, 0 to 3 weight percent of a rheology modifier, 0 to 10 weight percent of a plasticizer, and 0 to 20 weight percent of a filler. In a more preferred embodiment, based on the total weight of the heat-sealable coating, the heat-sealable coating comprises 60 to 90 weight percent of a polymer, 10 to 40 weight percent of a wax, 0 to 3 weight percent of a rheology modifier, 0 to 10 weight percent of a plasticizer, and 0 to 20 weight percent of a filler. In an even more preferred embodiment, the heat-sealable coating consists of 60 to 90 weight percent of a polymer, 10 to 40 weight percent of a wax, 0 to 3 weight percent of a rheology modifier, 0 to 10 weight percent of a plasticizer, and 0 to 20 weight percent of a filler. In the most preferred embodiment, the heat-sealable coating consists of 60 to 80 weight percent of a polymer, 20 to 40 weight percent of a wax, 0 to 3 weight percent of a rheology modifier, 0 to 10 weight percent of a plasticizer, and 0 to 20 weight percent of a filler. If a home-compostable paper is desired, then the heat-sealable coating does not contain a latex polymer.

[0115] The basis weight of the heat-sealable coating can vary depending on the specific application and end use of the coated paper. Generally, the basis weight of the heat-sealable coating can be from about 1 g / m 2 to about 25 g / m 2 , including all values in between in 1 g / m 2 increments. For example, the heat-sealable coating can have a basis weight equal to or greater than about 3 g / m 2 , such as equal to or greater than about 4 g / m 2 , such as equal to or greater than about 5 g / m 2 , such as equal to or greater than about 6 g / m 2 , such as equal to or greater than about 7 g / m 2 , such as equal to or greater than about 8 g / m 2 . The basis weight of the heat-sealable coating can be equal to or less than about 25 g / m 2 , such as equal to or less than about 23 g / m 2 , such as equal to or less than about 20 g / m 2 , such as equal to or less than about 18 g / m 2 , such as equal to or less than about 15 g / m 2 , such as equal to or less than about 14 g / m 2 .

[0116] The coated paper of the present invention preferably comprises a barrier coating and a heat-sealable coating. The barrier coating comprises only milk protein or a combination of milk protein and polyvinyl alcohol polymer. The heat-sealable coating comprises a vegetable wax, such as soybean wax, and a thermoplastic polysaccharide preferably derived from agricultural waste of corn. More preferably, based on the total weight of the barrier coating, the barrier coating comprises 50 to 80 weight percent of milk protein and 20 to 50 weight percent of polyvinyl alcohol polymer, even more preferably 55 to 75 weight percent of milk protein and 25 to 45 weight percent of polyvinyl alcohol polymer, and even more preferably 60 to 70 weight percent of milk protein and 30 to 40 weight percent of polyvinyl alcohol polymer.

[0117] The basis weight of the barrier coating containing milk protein is preferably 2 to 20 g / m 2 , more preferably 3 to 15 g / m 2 , even more preferably 7 to 12 g / m 2 . The basis weight of the heat-sealable coating containing vegetable wax and a thermoplastic polysaccharide preferably derived from agricultural waste of corn is preferably 2 to 20 g / m 2 , more preferably 3 to 15 g / m 2 , even more preferably 4 to 14 g / m 2 .

[0118] As described above, both the barrier coating and the heat-sealable coating are applied to the cellulose layer. The cellulose layer can be made of various different cellulose fibers, for example. Generally, the cellulose layer can have a basis weight of about 20 g / m 2 to about 200 g / m 2 , including all numerical values of 1 g / m 2 increment therebetween. For example, the cellulose layer can have a basis weight equal to or greater than about 25 g / m 2 , such as equal to or greater than about 30 g / m 2 , such as equal to or greater than about 40 g / m 2 , such as equal to or greater than about 50 g / m 2 , such as equal to or greater than about 60 g / m 2 , such as equal to or greater than about 70 g / m 2 . The basis weight of the cellulose layer is generally equal to or less than about 200 g / m 2 , such as equal to or less than about 120 g / m 2 , such as equal to or less than about 110 g / m 2 , such as equal to or less than about 100 g / m 2 , such as equal to or less than about 90 g / m 2 , such as equal to or less than about 80 g / m 2 , such as equal to or less than about 70 g / m2 , for example, equal to or less than approximately 60 g / m 2 .

[0119] The cellulose layer preferably has a thickness of 35 to 200 μm, more preferably 40 to 160 μm. If the cellulose layer has not been subjected to a step of longitudinal compression to obtain a stretchable cellulose layer, then the thickness of the cellulose layer is further preferably 40 to 70 μm, most preferably 50 to 60 μm. If the cellulose layer has been subjected to a step of longitudinal compression (such as wrinkling), then the cellulose layer preferably has a thickness of 60 to 150 μm, most preferably 60 to 120 μm, after longitudinal compression.

[0120] The basis weight of the coated paper or the entire product can generally be from about 21 g / m 2 to about 250 g / m 2 , including all numerical increments of 1 g / m therebetween. For example, the coated paper can have a basis weight equal to or greater than about 30 g / m 2 , for example, equal to or greater than about 35 g / m 2 , for example, equal to or greater than about 40 g / m 2 , for example, equal to or greater than about 45 g / m 2 , for example, equal to or greater than about 50 g / m 2 , for example, equal to or greater than about 55 g / m 2 , for example, equal to or greater than about 60 g / m 2 , for example, equal to or greater than about 65 g / m 2 , for example, equal to or greater than about 70 g / m 2 The basis weight of the coated paper can generally be equal to or less than about 150 g / m 2 , for example, equal to or less than about 125 g / m 2 , for example, equal to or less than about 100 g / m 2 , for example, equal to or less than about 95 g / m 2 , for example, equal to or less than about 90 g / m 2 , for example, equal to or less than about 85 g / m 2 , for example, equal to or less than about 80 g / m 2 .

[0121] The basis weight of the cellulose layer and the coated paper is determined in accordance with ISO 536:2019-11. The thickness of the cellulose layer and the coated paper can be determined in accordance with EN ISO 534:2012-02 under a compression load of 1.0 bar.

[0122] The cellulose layer can be made from any suitable papermaking fibers. For example, fibers suitable for making the cellulose layer include any natural or synthetic cellulose fibers, including but not limited to non-wood fibers such as cotton, manila hemp, kenaf, Indian grass, flax, reed grass, straw, jute, bagasse, milkweed, and linen fibers. In one aspect, the cellulose layer contains wood or pulp fibers, such as fibers obtained from deciduous and coniferous trees. Such fibers can include softwood fibers, such as northern and southern softwood kraft fibers. Other fibers include hardwood fibers, such as eucalyptus fibers, maple fibers, birch fibers, and poplar fibers.

[0123] Other papermaking fibers that can be used include waste paper or recycled fibers and high-yield fibers. High-yield pulp fibers are papermaking fibers produced by a pulping process with a yield of about 65% or higher, such as about 75% to about 95%. Such pulping processes include bleached chemi-thermomechanical pulp, chemi-thermomechanical pulp, other thermomechanical pulp, high-yield sulfite pulp, and high-yield sulfate pulp.

[0124] In a specific embodiment, the cellulose layer is made only of softwood fibers or a combination of softwood fibers and hardwood fibers.

[0125] The cellulose layer can be extensible. When the cellulose layer is extensible, the coated paper undergoes significant deformation during conversion or end-use applications.

[0126] When the cellulose layer is extensible, the coated paper of the present invention exhibits improved elongation and elasticity, especially in the machine direction. Therefore, the coated paper with an extensible cellulose layer ("extensible coated paper") exhibits mechanical properties comparable to those of plastic films commonly used as packaging materials. Therefore, due to its increased elongation and elasticity, the extensible coated paper is further suitable for use on the same machines used for plastic packaging.

[0127] In addition, it has been found that compressing the cellulose layer in the machine direction can improve the coating adhesion and heat sealability of the coated paper, and such compression can be carried out, for example, by wrinkling.

[0128] High extensibility of the cellulose layer can be produced by compressing the cellulose layer in the machine direction (MD), preferably by compressing a wet or dry paper web in the machine direction (MD).

[0129] Compression in the machine direction can be achieved by subjecting the cellulose layer to a wrinkling step or by using a Clupak device. These processes will be described in more detail below.

[0130] A stretchable coated paper within the meaning of the present invention is a coated paper having a longitudinal tensile strength and a longitudinal elongation at break defined as follows. More specifically, within the meaning of the present invention, the stretchable coated paper has a longitudinal tensile strength of preferably 40 - 120 N / 15 mm, more preferably 60 - 100 N / 15 mm, and has a longitudinal elongation at break of preferably 3.5 - 25.0%, more preferably 4.5 - 15.0%, still more preferably 5.5 - 12.0%, and most preferably 6.0 - 8.0%. In a particularly preferred embodiment, the stretchable coated paper has a longitudinal tensile strength of 60 - 100 N / 15 mm and a longitudinal elongation at break of 6.0 - 8.0%.

[0131] The longitudinal tensile strength of the coated paper is preferably 40 - 120 N / 15 mm, more preferably 60 - 100 N / 15 mm. The transverse tensile strength of the heat-sealable paper is 15 - 70 N / 15 mm, more preferably 20 - 60 N / 15 mm, and most preferably 30 - 50 N / 15 mm.

[0132] The Cobb value of the coated paper measured on the side containing the coating is preferably 1 - 20 g / m 2 and more preferably 1 - 12 g / m 2 and still more preferably 1 - 8 g / m 2 .

[0133] The coated paper preferably has a longitudinal tear resistance of 100 - 1000 mN, more preferably 300 - 800 mN, and still more preferably 500 - 800 mN. The transverse tear resistance is preferably 100 - 1000 mN, more preferably 300 - 800 mN, and still more preferably 500 - 800 mN.

[0134] The coated paper preferably has a longitudinal elongation at break of 3.5 - 25.0%, more preferably 4.5 - 8.0%, and still more preferably 6.0 - 7.0%.

[0135] When the cellulose layer used in the coated paper of the present invention undergoes a longitudinal compression step, the coated paper is further suitable for use on the same machine for plastic packaging because its ductility, elongation, elasticity, and coating adhesion are improved.

[0136] The longitudinal compression can be achieved by subjecting the cellulose layer to a wrinkling step. Wrinkling can be carried out inside the paper machine (wet wrinkling) or outside the paper machine (dry wrinkling).

[0137] More specifically, during creping, the cellulose layer moves on the creping drum and is removed by a doctor blade, reaching the transfer device after passing over the surface of the doctor blade. Creping is controlled by reducing the speed of the transfer device relative to the creping drum, preferably by 10% to 50%. The degree of creping, i.e., the number of folds, can be controlled by adjusting the speed difference between the creping drum and the transfer device. In addition, the microstructure can be controlled by the geometry and angle of the doctor blade. During this process, the dry content of the cellulose layer is preferably in the range of 30 to 50 weight percent, more preferably 35 to 45 weight percent.

[0138] Longitudinal compression of the cellulose layer can also be achieved by using a Clupak device.

[0139] The Clupak extensible unit includes a drum, a nip bar, the gap between the drum and the nip bar, and a rubber belt (rubber blanket) located in the gap. In the Clupak extensible unit, the rubber blanket must pass through the gap between the dryer cylinder and the nip bar.

[0140] The nip can be regarded as a Venturi section formed by a rotating dryer cylinder and a static nip bar, in which the annular rubber blanket is accelerated. Due to the frictional force between the paper and the rubber, the paper web follows the dimensional changes of the rubber surface in the nip. This is the result of high radial nip pressure and the simultaneous sliding of the paper on the drum surface. The dimensional changes of the rubber surface are caused by bending and the Venturi effect. First, the rubber blanket surface closer to the paper web is stretched by bending over the nip bar and further stretched due to the Venturi effect. Then, the stretched rubber surface comes into contact with the wet paper web. After passing through the center of the nip, the stretched rubber surface begins to rebound due to the deceleration caused by the Venturi effect and the bending of the rubber in the opposite direction. The paper web is compacted in the MD direction while following the contraction of the rubber surface in the second half of the nip, and these conditions in the nip become more pronounced as the width of the nip increases. The final compression level is adjusted by controlling the speed difference of the paper web between the inlet and the outlet of the Clupak nip.

[0141] Using a Clupak unit to longitudinally compress the cellulose layer produces a slightly wrinkled effect in the paper web through the curling of the fibers. The cellulose layer is compressed, so the fibers are pushed closer to each other, causing the cellulose layer to be compressed longitudinally. In this way, a series of very small, usually discontinuous parallel folds are imparted to the cellulose layer. The slightly wrinkled effect is mainly different from creping in that there are more folds imparted, and thus more overlapping folds. It has surprisingly been found that compared to creping using a creping drum, the slightly wrinkled effect not only improves the elongation of the paper substrate but also further increases the adhesion of the subsequently applied coating. In addition, the slightly wrinkled effect improves the heat sealability of the coated paper.

[0142] The cellulose layer that can be used to produce the coated paper of the present invention undergoes a calendering step before coating.

[0143] The coated paper of the present invention can also undergo a calendering step after the coating and drying steps.

[0144] Calendering improves the smoothness and gloss of the coated paper.

[0145] Hereinafter, preferred embodiments of the present invention will be described.

[0146] In one embodiment, the coated paper includes:

[0147] A cellulose layer having a first side and an opposite second side; a barrier coating applied to at least the first side of the cellulose layer, wherein the barrier coating contains milk protein (the amount of the milk protein is preferably 50 to 80 weight percent, more preferably 55 to 75 weight percent, and even more preferably 60 to 70 weight percent relative to the weight of the barrier coating); and

[0148] A heat-sealable coating applied on the barrier coating, the heat-sealable coating containing soy wax and a thermoplastic polysaccharide, the thermoplastic polysaccharide preferably derived from agricultural waste of corn. If a home-compostable paper is desired, then the heat-sealable coating does not contain latex.

[0149] In another embodiment, the coated paper includes:

[0150] A cellulose layer having a first side and an opposite second side; a barrier coating applied to at least the first side of the cellulose layer, wherein the barrier coating contains milk protein (the amount of the milk protein is preferably 50 to 80 weight percent, more preferably 55 to 75 weight percent, and even more preferably 60 to 70 weight percent relative to the weight of the barrier coating) and a polyvinyl alcohol polymer (the amount of the polyvinyl alcohol polymer is preferably 20 - 50 weight percent, more preferably 25 to 45 weight percent, and even more preferably 30 to 40 weight percent relative to the weight of the barrier coating); and a heat-sealable coating applied on the barrier coating, the heat-sealable coating containing soy wax and a thermoplastic polysaccharide, the thermoplastic polysaccharide preferably derived from agricultural waste of corn. If a home-compostable paper is desired, then the heat-sealable coating does not contain latex.

[0151] In the above preferred embodiments, the basis weight is more preferably in the following ranges: 30 to 70 g / m for the cellulose layer 2 , 8 to 20 g / m for the barrier coating 2 , and 4 to 15 g / m for the heat-seal coating 2 .

[0152] In another aspect, the present disclosure relates to a method of manufacturing a coated paper.

[0153] In one aspect, the method according to the present disclosure comprises the steps of: providing a cellulose layer, and applying an aqueous solution or aqueous dispersion (“barrier coating composition”) to one side of the cellulose layer. The aqueous solution or aqueous dispersion contains components derived from plants or animals. The applied aqueous solution or aqueous dispersion is dried to form a barrier coating on the cellulose layer. Then, an aqueous dispersion or emulsion (“heat-sealable coating composition”) is applied on the barrier coating. The aqueous dispersion or emulsion may contain only wax, or a combination of wax and polymer. The aqueous dispersion or emulsion is applied in a manner that covers the barrier coating. Then, the aqueous dispersion or emulsion is dried to form a heat-sealable coating on the barrier coating.

[0154] In one aspect, initially, the cellulose layer can be saturated with an aqueous composition containing components derived from plants or animals, which are preferably water-soluble or water-dispersible, more preferably water-soluble; subsequently, the cellulose layer is coated with an aqueous dispersion or emulsion that forms a heat-sealable coating.

[0155] In another aspect, initially, the cellulose layer can be saturated with at least one compound selected from the group consisting of wax, polyester, polysaccharide, polysaccharide ester, polysaccharide ether, polysaccharide ether ester, glycerol, polyethylene glycol, polyvinyl alcohol, softening agent, and inorganic filler.

[0156] In this specification, the term “saturate” is understood to be synonymous with “impregnate”. The amounts of different saturating components in the heat-sealable paper are 2 - 20 g / m 2 , preferably 3 - 15 g / m 2 , even more preferably 4 - 12 g / m 2 . When the coating is applied only on one side of the cellulose layer, it is preferred to saturate the cellulose layer.

[0157] As described above, the barrier coating and the heat-sealable coating can be applied only on one side of the cellulose layer. Alternatively, each side of the cellulose layer can include a barrier coating and a heat-sealable coating. If a barrier coating is formed on the cellulose layer, then any suitable method or technique can be used to form a heat-sealable coating on the barrier coating, followed by curing and / or drying. For example, the heat-sealable coating composition can be applied to the surface of the barrier coating by spraying, brushing, or roll coating to form a heat-sealable coating. When the heat-sealable coating composition is applied to the surface of the barrier coating, a film-forming process occurs.

[0158] Preferably, a liquid heat-sealable coating composition of lower viscosity is applied to the barrier coating and cured to form a solid, high molecular weight polymer-based adhesive film. A heat-sealable coating can also be formed by coalescence-based film formation. Coalescence-based film formation is carried out with polymer particles dispersed in a liquid phase, preferably with latex polymers, most preferably with an aqueous dispersion polymer selected from the group consisting of polyester, polysaccharide, polysaccharide ester, polysaccharide ether, and polysaccharide ether ester in combination with wax.

[0159] The heat-sealable coating composition can be an aqueous dispersion or emulsion containing wax. The wax is preferably the wax defined in the first aspect of the present invention. In other words, the wax is preferably a bio-based wax, more preferably a plant wax or an animal wax, and even more preferably a plant wax. The wax contained in the heat-sealable coating composition is even more preferably one or more waxes selected from the group consisting of candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, pea wax, coconut wax, palm tree wax, and beeswax, and most preferably soybean wax. The wax preferably has a dropping point in the range of 60°C to 120°C.

[0160] The heat-sealable coating composition is preferably an aqueous emulsion containing wax, more preferably an aqueous emulsion containing wax and an emulsifier.

[0161] An emulsifier is a compound that generally has a polar part and a non-polar part. A surfactant can be used as an emulsifier. The emulsifier is preferably an anionic emulsifier or a non-ionic emulsifier, and more preferably an anionic emulsifier.

[0162] Based on the total weight of the heat-sealable coating composition, the solid content of the heat-sealable coating composition as an aqueous dispersion or emulsion containing wax is preferably 10 - 45 weight percent. The viscosity of the barrier coating composition is preferably 200 to 1600 mPas, and more preferably 500 to 1200 mPas.

[0163] After applying the barrier coating composition and the heat-sealable coating composition, the coating compositions are dried to form a barrier coating and a heat-sealable coating, respectively. In one aspect, the barrier coating composition can be applied and dried, then the heat-sealable coating composition is applied, and then dried. Drying can be carried out by blowing hot dry air onto the coating to raise the coating temperature to the temperature point at which water evaporates from the coated paper, leaving a drier coated paper. During the drying process, the web temperature (i.e., the temperature of the cellulose layer) must be lower than the dropping point of the wax. Therefore, the web temperature during drying is preferably below 120°C. The web temperature of the paper can be determined by non-contact temperature measurement using an infrared non-contact thermometer.

[0164] The cellulose layer can be a wet-laid substrate, which can also be extensible. The cellulose layer is fed into a first coater, where an aqueous composition is applied to one side of the cellulose layer. To form a coating with a desired thickness and / or basis weight on the cellulose layer, a barrier coating can be applied by different coating techniques such as a rod coater, a curtain coater, or an air knife. In this embodiment, the first coating or the barrier coating is subsequently dried.

[0165] A heat-sealable coating is applied by using any of the above coating techniques. Then the heat-sealable coating is dried in a second drying step.

[0166] The coated paper can be sent from the second drying position to a one nip calender and then to a cooling roll. A winding device is provided at the end.

[0167] Alternatively, a barrier coating can be formed on one side of the cellulose layer by extrusion. Thus, the barrier coating composition is extruded onto one side of the cellulose layer to form a barrier coating.

[0168] Test method:

[0169] The moisture vapor transmission rate (MVTR) can be determined at 50% relative humidity and a temperature of 23 °C in accordance with DIN EN ISO 15106-3:2005-01.

[0170] The "oxygen transmission rate" (OTR) can be determined at 50% relative humidity and a temperature of 23 °C in accordance with DIN EN ISO test 15105-2:2003.

[0171] The tensile strength and elongation at break can be determined in accordance with ISO 1924:2016-08.

[0172] The tear resistance can be measured in accordance with the ISO 1974:2012 standard.

[0173] The basis weight of the cellulose layer and the coated paper can be determined in accordance with ISO 536:2019-11. The basis weight of the barrier coating and the heat-sealable coating can be calculated therefrom.

[0174] The thickness can be determined at a compressive load of 1.0 bar in accordance with EN ISO 534:2012-02.

[0175] The Cobb value can be determined in accordance with ISO 535:2014. The sample is measured after 10 minutes.

[0176] The present disclosure can be better understood with reference to the following examples.

[0177] Embodiment

[0178] Coated paper was manufactured according to the present disclosure and various properties were tested. The coated paper includes a cellulose layer, which includes a wet-laid fiber web made of FSC-certified log pulp fibers (such as softwood fibers), and the fiber web has a basis weight of about 60 g / m 2 . One side of the cellulose layer was coated with a barrier coating composition containing milk protein to form a barrier coating. The barrier coating composition was prepared by mixing milk protein provided as particles with cold water and stirring for 2 hours to obtain a uniform coatable solution. The barrier coating composition has a dry content of 15% milk protein. The barrier coating has a basis weight of about 10 g / m 2 . The coated paper further includes a heat-sealable coating applied on the barrier coating. The heat-sealable coating contains soy wax combined with a thermoplastic polysaccharide, and the thermoplastic polysaccharide is derived from agricultural waste of corn and has a basis weight of about 10 g / m 2 . The following results were obtained:

[0179]

[0180]

[0181] Those of ordinary skill in the art can make these and other modifications and variations to the present invention without departing from the spirit and scope of the present invention as more specifically set forth in the appended claims. Additionally, it should be understood that aspects of various embodiments can be interchanged fully or partially. Moreover, those of ordinary skill in the art should understand that the above description is merely exemplary and not intended to limit the present invention, which is defined only by the appended claims.

[0182] The following items are also part of the present disclosure:

[0183] [Item 1] A method for manufacturing coated paper, comprising:

[0184] providing a cellulose layer;

[0185] applying an aqueous solution or aqueous dispersion of a component derived from a plant or an animal to one side of the cellulose layer;

[0186] drying the applied aqueous solution or aqueous dispersion to form a barrier coating on the cellulose layer, coating a water dispersion or emulsion of a coating composition containing wax on the barrier coating; and drying the water dispersion or emulsion to form a heat-sealable coating on the barrier coating.

[0187] [Item 2] The method according to Item 1, wherein the cellulose layer is subjected to a step of compressing the cellulose layer in the longitudinal direction before coating to provide a stretchable cellulose layer.

[0188] [Item 3] The method as defined in item 2, wherein the cellulose layer is longitudinally compressed by subjecting the cellulose layer to a creping step.

[0189] [Item 4] The method as defined in item 3, wherein, in the step of creping the cellulose layer, the cellulose layer moves on a creping drum and is removed by a doctor blade, passes through the surface of the doctor blade and reaches a transfer device, and the creping is controlled by reducing the speed of the transfer device by 10% to 50% relative to the creping drum.

[0190] [Item 5] The method as defined in item 2, wherein the step of longitudinally compressing the cellulose layer occurs in a Clupak extensible unit, and the Clupak extensible unit includes a drum, a pressure bar, a gap between the drum and the pressure bar, and a rubber belt located in the gap.

[0191] [Item 6] The method as defined in any one of items 1 to 5, wherein the barrier coating and the heat-sealable coating are formed on both sides of the cellulose layer.

[0192] [Item 7] The method as defined in any one of items 1 to 5, wherein the barrier coating and the heat-sealable coating are only formed on one side of the cellulose layer.

[0193] [Item 8] The method as defined in any one of items 1 to 7, wherein at least one side of the cellulose layer is subjected to a saturation step before coating.

[0194] [Item 9] The method as defined in item 8, wherein the cellulose layer is saturated with at least one compound selected from the group consisting of wax, polyester, polysaccharide, polysaccharide ester, polysaccharide ether, polysaccharide ether ester, glycerol, polyethylene glycol, polyvinyl alcohol, softening agent, and inorganic filler.

Claims

1. A coated paper comprising: a cellulose layer having a first side and an opposing second side; a barrier coating applied to at least a first side of the cellulosic layer, wherein the barrier coating comprises a component derived from a plant or animal; and A heat sealable coating is applied over the barrier coating, the heat sealable coating comprising a wax.

2. The coated paper according to claim 1, wherein the plant- or animal-derived component is water-soluble or water-dispersible, preferably water-soluble.

3. A coated paper according to claim 1 or claim 2, wherein the plant or animal derived component is amorphous.

4. A coated paper according to any one of the preceding claims, wherein the vegetable or animal derived component is a milk protein.

5. Coated paper according to any one of the preceding claims, wherein the barrier coating does not comprise fatty acid sugar esters.

6. The coated paper according to any one of the preceding claims, wherein the barrier coating has a g / m 2 and equal to or less than about 25 g / m 2 , for example, equal to or less than about 20 g / m 2 , for example, equal to or less than about 18 g / m 2 The basis weight.

7. Coated paper according to any one of the preceding claims, wherein the barrier coating consists of a component of plant or animal origin and a polyvinyl alcohol polymer and optionally a filler.

8. The coated paper according to claim 7, wherein the barrier coating consists of 10 to 50 weight percent, for example 10 to 20 weight percent, of a component derived from plants or animals and the balance is a polyvinyl alcohol polymer.

9. The coated paper according to any one of claims 1 to 6, wherein the barrier coating further comprises a polyvinyl alcohol polymer and / or nanocrystalline cellulose.

10. The coated paper according to any one of the preceding claims, wherein the coated paper exhibits a viscosity of less than about 10 g / m 2 / 24 hours moisture vapor transmission rate (MVTR) and less than about 2cm 3 / m 2 / 24-hour oxygen transmission rate (OTR).

11. A coated paper according to any one of the preceding claims, wherein the coated paper has been calendered.

12. A coated paper according to any one of the preceding claims, wherein the wax is a vegetable wax.

13. The coated paper according to claim 12, wherein the vegetable wax is one or more vegetable waxes selected from the group consisting of candelilla wax, carnauba wax, rice bran wax, soy wax, sugar cane wax, sunflower wax, pea wax, coconut wax and palm wax, preferably soy wax.

14. The coated paper according to any one of the preceding claims, wherein the heat-sealable coating further comprises a polymer selected from the group consisting of polyesters, polysaccharides, polysaccharide esters, polysaccharide ethers, polysaccharide ether esters and latex polymers.

15. The coated paper according to claim 14, wherein the polymer is thermoplastic starch.

16. Coated paper according to any one of the preceding claims, wherein the coated paper passes the compostability test EN 13432:2001.

17. The coated paper according to any one of the preceding claims, wherein the coated paper is free of petroleum based synthetic polymers.

18. The coated paper according to any one of the preceding claims, wherein the coated paper does not contain any adhesive layer between the barrier coating and the first side of the cellulosic layer or between the barrier coating and the heat-sealable coating.

19. A coated paper according to any one of the preceding claims, wherein the basis weight of the heat sealable coating is about 1 g / m 2 Up to about 25g / m 2 , for example about 3g / m 2 Up to about 20g / m 2 , for example about 4g / m 2 Up to about 15g / m 2 .

20. The coated paper according to any one of the preceding claims, wherein the cellulose layer has a thickness of about 20 g / m 2 Up to about 100g / m 2 , for example about 30g / m 2 Up to about 70g / m 2 The basis weight.

21. The coated paper according to any one of the preceding claims, wherein the cellulosic layer comprises wood pulp fibers, bast fibers or mixtures thereof.

22. The coated paper according to any one of the preceding claims, wherein the coated paper has a thickness of about 25 g / m 2 Up to about 125g / m 2 , for example about 35g / m 2 Up to about 90g / m 2 , for example about 40g / m 2 Up to about 80g / m 2 The basis weight.

23. A package comprising a coated paper as claimed in any preceding claim.

24. A method for making coated paper, comprising: providing a cellulose layer; applying an aqueous solution or dispersion of a plant or animal derived component to one side of the cellulose layer; drying the applied aqueous solution or dispersion to form a barrier coating on the cellulose layer, and applying an aqueous dispersion or emulsion of a coating composition comprising a wax on the barrier coating; and The aqueous dispersion or emulsion is dried to form a heat-sealable coating on top of the barrier coating.

25. The method according to claim 24, wherein the coated paper is a coated paper according to any one of claims 2 to claim 22.

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