Aqueous coating composition

Abstract

The present invention relates to an aqueous coating composition. The aqueous coating composition comprises (a) a polymer A comprising units derived from an alpha-olefin and one or more comonomers selected from the group consisting of methacrylate, acrylate, methacrylic acid, acrylic acid, maleate, maleic acid, maleic anhydride and salts thereof; (b) a polymer B comprising units derived from one or more monomers selected from the group consisting of methacrylate, acrylate, methacrylic acid, acrylic acid, maleate, maleic acid, maleic anhydride and salts thereof; (c) a calcium carbonate-containing material in an amount of from 0.1 wt-% to less than 20 wt-%, based on the total dry weight of the coating composition; and (d) optionally, a wax. Furthermore, the present invention also relates to a process for preparing the aqueous coating composition of the present invention and to a coated article.

Description

Technical Field

[0001] This invention relates to aqueous coating compositions and methods for preparing the same. The invention also relates to articles, such as paper or paperboard, coated with the aqueous coating compositions, which can be used as packaging for beverages and / or food. Background Technology

[0002] Cellulose-based packaging materials such as paper, cardboard, and pallets for beverages or food are becoming increasingly important as alternatives to traditional plastic containers. Paper-based products must meet certain requirements to be used as beverage or food packaging materials and ultimately accepted by industries and customers with such needs. For example, paper-based packaging typically must have certain minimum water and water vapor barrier properties. Certain minimum values ​​in cold and hot water absorption tests (also known as COBB tests) and water vapor transmission rate (WVTR) are required. Additionally, the packaging must be grease-resistant or oil-resistant. Furthermore, paper-based packaging often must be sealable or heat-sealable to form structures such as cups or containers, or to provide lids or other types of seals for such structures.

[0003] Paper or fiber-based substrates typically fail to meet any of the aforementioned requirements of the packaging industry. This is why paper is often laminated or extruded with polymer films, such as PE films, to impart one or more desired functions to the paper. While polymer film lamination enhances the functionality of paper as a packaging material, it often complicates the recyclability of the cellulose components of the packaging. This is primarily due to the relatively high lamination weight of polymer films. Water-based coating compositions offer improved recyclability compared to conventional polymer films. However, coatings prepared from water-based compositions often cannot simultaneously provide a paper substrate with all the desired properties (e.g., barrier properties against hot and cold water and oil; sealing ability; recyclability, etc.) while maintaining processability and cost-effectiveness. For example, some coatings may not be sufficiently resistant to hot tea, coffee, or other hot beverages, limiting their use in applications such as coffee travel mugs.

[0004] Therefore, there is a continued need in the art for an aqueous coating composition that can provide improved performance, particularly improved hot water barrier properties, for cellulose-based substrates used in packaging, while maintaining processability and cost-effectiveness. Summary of the Invention

[0005] One object of the present invention is to provide an improved aqueous coating composition and an improved article coated thereon. Invention Overview

[0007] One aspect of the present invention relates to an aqueous coating composition. The aqueous coating composition comprises...

[0008] (a) Polymer A, comprising units derived from α-olefins and one or more comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0009] (b) Polymer B, comprising units derived from one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts;

[0010] (c) A calcium carbonate-containing material comprising 0.1% to less than 20% by weight of the total dry weight of the coating composition; and

[0011] (d)Optional, wax.

[0012] A key inventive finding of this invention is that the addition of a specific amount of calcium carbonate-containing material (preferably high-purity calcium carbonate) to an aqueous polymer formulation can improve the performance of coatings prepared from such an aqueous coating formulation. Specifically, the addition of this specific amount of calcium carbonate-containing material reduces the hot water absorption of the coated paper product. Therefore, the stability of the coated paper to hot water is increased. Simultaneously, other important parameters of the coated product, such as sealing ability, cold water COBB, and WVTR, are largely maintained. Therefore, the coating compositions of this invention are particularly suitable for paper-based packaging that must resist hot liquids, such as cups for hot drinks or food containers that are heated to prepare food therein.

[0013] It has been further discovered that articles incorporating the coating of the present invention can be processed better in hot air sealing machines compared to similar coatings without calcium carbonate materials. In particular, coated articles according to the present invention exhibit less clogging in coating and sealing machines.

[0014] Another aspect of the present invention relates to a method for preparing the aqueous coating composition of the present invention. The method includes the following steps:

[0015] Provides an aqueous composition I comprising polymer A and optional wax,

[0016] Provides an aqueous composition II comprising polymer B and optional wax.

[0017] Provide materials containing calcium carbonate.

[0018] The aqueous compositions I and II are mixed with the calcium carbonate-containing material.

[0019] Another aspect of the invention relates to a coated article. The coated article comprises a substrate, wherein at least one surface of the substrate comprises a coating prepared from an aqueous coating composition according to the invention.

[0020] Preferred embodiments of the present invention are defined in the dependent claims.

[0021] According to one embodiment of the present invention, the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 50:50 to 99:1, preferably >65:<35 to 99:1, more preferably 70:30 to 99:1, and most preferably 75:25 to 95:5.

[0022] According to one embodiment of the invention, the aqueous coating composition comprises a combination of polymers A and B in an amount of 60-99.9% by weight, preferably 75-99.9% by weight, more preferably 85-95% by weight, based on the total dry weight of the coating composition.

[0023] According to one embodiment of the invention, the aqueous coating composition comprises 0.1-12.5% ​​by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight of the calcium carbonate-containing material based on the total dry weight of the coating composition, and / or the calcium carbonate-containing material has a calcium carbonate content of at least 90% by weight, preferably at least 95% by weight based on the total weight of the calcium carbonate-containing material.

[0024] According to one embodiment of the present invention, the aqueous coating composition comprises:

[0025] (a) 50 to 99, preferably >65 to 95, more preferably 70 to 95 parts by weight of polymer A.

[0026] (b) 1 to 50, preferably 5 to <35, more preferably 5 to 25 parts by weight of polymer B,

[0027] (c) 1 to <20, preferably 1 to 15, more preferably 2 to 9 parts by weight of the calcium carbonate-containing material, and

[0028] (d) Optionally, 1 to 15, preferably 5 to 12, more preferably 7 to 12 parts by weight of wax.

[0029] According to one embodiment of the present invention, polymer A comprises, preferably, a unit derived from, an α-olefin, preferably ethylene, and one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, and their salts.

[0030] According to one embodiment of the present invention, polymer A is a copolymer of ethylene and acrylic acid.

[0031] According to one embodiment of the present invention, polymer A has a comonomer content, preferably an acrylic acid content, of 0.5-25% mol, more preferably 5-25% mol.

[0032] According to one embodiment of the present invention, polymer A has a comonomer content, preferably an acrylic acid content, of 5-30% by weight.

[0033] According to one embodiment of the present invention, polymer B comprises, preferably, a unit derived from one or more, preferably two to four, monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, and their salts.

[0034] According to one embodiment of the present invention, polymer B is a polymer of acrylic acid and one to three C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate monomers.

[0035] According to one embodiment of the present invention, the calcium carbonate-containing material has a median particle size d. 50 The particle size is 0.1-15 micrometers, preferably 0.1-5 micrometers, more preferably 0.1 micrometers to less than 0.8 micrometers, and / or the calcium carbonate-containing material has a top-cut weight particle size d. 98 The micrometer range is 0.5-30 micrometers, preferably 0.5-20 micrometers, and more preferably 0.5 micrometers to less than 4 micrometers.

[0036] According to one embodiment of the invention, the wax is a hydrocarbon wax, preferably paraffin wax.

[0037] According to one embodiment of the present invention, the aqueous coating composition has a solid content of 5-70% by weight, preferably 20-60% by weight, more preferably 30-50% by weight, and / or the aqueous coating composition has a pH value of 7.5-12, preferably 8-11, more preferably 8-9.5.

[0038] According to one embodiment of the present invention, the substrate is a cellulose-based substrate, plastic or metal, preferably a cellulose-based substrate, and more preferably paper, paperboard or cardboard.

[0039] According to one embodiment of the invention, the coated article comprises a pre-coating between at least one surface of the substrate and the coating, wherein the pre-coating comprises at least one mineral (preferably talc and / or calcium carbonate) and a binder.

[0040] For the purposes of this invention, the following terms shall have the following meanings:

[0041] "A polymer comprising units derived from...(a particular monomer)" refers to a polymer obtained by polymerizing at least that particular monomer (such as methacrylate, methacrylic acid, etc.).

[0042] "Methacrylate" refers to an ester of methacrylic acid, and "acrylate" refers to an ester of acrylic acid. "Maleic acid ester" refers to a monoester or diester (preferably a diester) of maleic acid.

[0043] In this article, the "particle size" of granular materials is determined by the distribution of their particle size d. x To describe. Here, the value d x This refers to a diameter such that, relative to this diameter, x% of the weight of particles have a diameter less than d. x The diameter. This means, for example, d. 20 The value refers to a particle size in which 20% of the weight of all particles is less than that particle size. d 50 The value is therefore the weight-median particle size, that is, the particle size at which 50% of the weight of all particles is less than this particle size. For the purposes of this invention, unless otherwise specified, this particle size is specifically designated as the weight-median particle size d. 50 (wt). Particle size was determined using Sedigraph from Micromeritics Instrument Corporation. TM The 5120 instrument is used to determine the particle size. The methods and instrumentation are known to those skilled in the art and are commonly used to determine the particle size of fillers and pigments. Measurements can be performed in an aqueous solution of 0.1% by weight of Na₄P₂O₇.

[0044] In this invention, "calcium carbonate-containing material" refers to a mineral or synthetic material having a calcium carbonate content of at least 50% by weight based on the total weight of the calcium carbonate-containing material.

[0045] When referring to a singular noun, the use of indefinite or definite articles such as "a," "an," or "the" includes the plural form of that noun, unless otherwise specifically indicated. When the term "comprising" is used in this specification and claims, it does not exclude other elements.

[0046] For the purposes of this invention, the terms "consisting of" and "essentially consisting of" are considered preferred embodiments of the term "comprising". If a group is defined below as comprising at least a certain number of embodiments, this is also understood to disclose a group that preferably consists only of or substantially consists only of these embodiments.

[0047] Terms such as “obtainable” or “definable” and “obtained” or “defined” are used interchangeably. This means, for example, that unless the context explicitly indicates otherwise, the term “obtainable” does not imply that an embodiment must be obtained through a sequence of steps following the term “obtainable,” although the terms “obtainable” or “defined” always include such limiting understanding as a preferred embodiment.

[0048] Wherever the terms “including” or “having” are used, they are considered equivalent to “comprising” as defined above.

[0049] Detailed description

[0050] The various aspects and embodiments of the invention will be described in more detail below.

[0051] Waterborne coating compositions and their preparation methods

[0052] In one aspect, the present invention relates to an aqueous coating composition. The aqueous coating composition comprises...

[0053] (a) Polymer A, comprising units derived from α-olefins and one or more comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0054] (b) Polymer B, comprising units derived from one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts;

[0055] (c) A calcium carbonate-containing material comprising 0.1% to less than 20% by weight of the total dry weight of the coating composition; and

[0056] (d)Optional, wax.

[0057] Polymer A

[0058] The aqueous coating composition according to the invention comprises polymer A, which contains units derived from α-olefins and one or more (e.g., one to three) comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0059] The α-olefin is preferably a C2-C4 α-olefin, and most preferably ethylene.

[0060] Suitable methacrylates can be alkyl methacrylates, optionally C1-C6 alkyl methacrylates, such as methyl methacrylate or butyl methacrylate.

[0061] Suitable acrylates can be alkyl acrylates, optionally C1-C6 alkyl acrylates, such as methyl acrylate or butyl acrylate.

[0062] Suitable maleic esters may be dialkyl maleate, optionally diC1-C6 alkyl maleate.

[0063] According to a preferred embodiment, polymer A comprises, preferably, units derived from, α-olefins, preferably ethylene, and one or more (e.g., one to three) comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, and their salts.

[0064] Polymer A may have a specific comonomer content. Preferably, polymer A has a comonomer content (methacrylate, acrylate, methacrylic acid, maleate, maleic acid, maleic anhydride and / or acrylic acid) of 0.5-25% mol, more preferably 5-25% mol, more preferably 15-25% mol, for example 15-22% mol.

[0065] In another preferred embodiment, polymer A has a comonomer content (methacrylate, acrylate, methacrylic acid, maleate, maleic acid, maleic anhydride and / or acrylic acid) of 5-25% mol (e.g. 8-22% mol), more preferably 5-15% mol, and even more preferably 5-12% mol, e.g. 8-12% mol.

[0066] Polymer A can exist in a partially or completely neutralized form. In the context of polymers A and B, "neutralization" refers to the neutralization of the carboxylic acid groups of polymer units derived from methacrylic acid and / or acrylic acid by monovalent, divalent, and / or trivalent cations such as basic cations (e.g., Li). + Na + NH4 + Neutralization. According to one embodiment, polymer A exists in a partially neutralized form. According to a preferred embodiment, polymer A exists in a completely neutralized form.

[0067] According to a preferred embodiment, polymer A is a polymer of ethylene and acrylic acid, and optionally methacrylic acid. Most preferably, polymer A is a copolymer of ethylene and acrylic acid. The copolymer of ethylene and acrylic acid preferably has an acrylic acid comonomer content of 0.5-30% mol, more preferably 5-25% mol, more preferably 15-25% mol, such as 15-22% mol. For example, the acrylic acid content of the ethylene-acrylic acid copolymer can be about 20% mol. The ethylene-acrylic acid copolymer may have an acrylic acid weight content of 5-30% by weight, preferably 10-25% by weight, more preferably 12-20% by weight.

[0068] The copolymer of ethylene and acrylic acid preferably has an acrylic acid comonomer content of 5-25% mol (e.g., 8-22% mol), more preferably 5-15% mol, and even more preferably 5-12% mol, e.g., 8-12% mol. For example, the acrylic acid content of the ethylene-acrylic acid copolymer can be about 10% mol.

[0069] Suitable ethylene-acrylic acid copolymers have CAS number 9010-77-9.

[0070] Polymer A may be present in the water-based coating composition at a weight content of 55-98% by weight, preferably 60-85% by weight, more preferably 60-80% by weight, or even more preferably 60-70% by weight, based on the total dry weight of the coating composition.

[0071] Polymer B

[0072] The aqueous coating composition according to the invention comprises polymer B, which contains units derived from one or more (e.g., one to five) monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0073] It should be understood that polymer A and polymer B are different polymers, which means that for the purposes of this invention, at least one polymer unit in polymer A is different from one or more polymer units in polymer B.

[0074] Suitable methacrylate monomers include methyl methacrylate, butyl methacrylate, hexyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, sec-butyl methacrylate, cyclohexyl methacrylate, isodecanyl methacrylate, isobornyl methacrylate, tert-butylaminoethyl methacrylate, stearyl methacrylate, glycidyl methacrylate, dicyclopentenyl methacrylate, and phenyl methacrylate. Preferred methacrylate monomers are methyl methacrylate, butyl methacrylate, hexyl methacrylate, isobutyl methacrylate, and isopropyl methacrylate. More preferred methacrylate monomers are butyl methacrylate and methyl methacrylate.

[0075] Suitable acrylate monomers are methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate and isooctyl acrylate, n-decyl acrylate, isodecyl acrylate, tert-butyl acrylate and 2-hydroxyethyl acrylate. Preferred acrylate monomers are methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate and isooctyl acrylate, n-decyl acrylate, isodecyl acrylate, tert-butyl acrylate and 2-hydroxyethyl acrylate. More preferred acrylate monomers are methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate and isooctyl acrylate.

[0076] Suitable maleic esters are dialkyl maleates, optionally di-C1-C6 alkyl maleates.

[0077] Polymer B can be present in a partially or completely neutralized form. According to one embodiment, the first polymer is present in a partially neutralized form. According to a preferred embodiment, the second polymer is present in a completely neutralized form.

[0078] According to one embodiment, polymer B comprises units derived from one or more (e.g., one to five) monomers selected from alkyl methacrylates, alkyl acrylates, methacrylic acid, acrylic acid, dialkyl maleate, maleic acid, maleic anhydride, and their salts. According to one embodiment, polymer B comprises units derived from one or more (e.g., one to five) monomers selected from alkyl methacrylates, alkyl acrylates, methacrylic acid, acrylic acid, and their salts. According to a preferred embodiment, polymer B comprises units derived from one or more, preferably two to four, monomers selected from C1-C6 alkyl methacrylates, C1-C6 alkyl acrylates, methacrylic acid, acrylic acid, di-C1-C6 alkyl maleate, maleic acid, maleic anhydride, and their salts. According to a preferred embodiment, polymer B comprises units derived from one or more, preferably two to four, monomers selected from C1-C6 alkyl methacrylates, C1-C6 alkyl acrylates, methacrylic acid, acrylic acid, and their salts. According to a preferred embodiment, polymer B comprises units derived from one to five, preferably two to four, monomers selected from C1-C6 alkyl methacrylates, C1-C6 alkyl acrylates, methacrylic acid, acrylic acid, and their salts.

[0079] According to one embodiment, polymer B comprises, preferably, a unit derived from one or more, preferably two to four monomers, wherein the monomers are selected from alkyl methacrylates, alkyl acrylates, methacrylic acid, acrylic acid, and their salts. According to a preferred embodiment, polymer B comprises a unit derived from one or more, preferably two to four monomers, wherein the monomers are selected from C1-C6 alkyl methacrylates, C1-C6 alkyl acrylates, methacrylic acid, acrylic acid, and their salts. According to a preferred embodiment, polymer B comprises a unit derived from one to five, preferably two to four, monomers, wherein the monomers are selected from C1-C6 alkyl methacrylates, C1-C6 alkyl acrylates, methacrylic acid, acrylic acid, and their salts.

[0080] According to a preferred embodiment of the invention, polymer B is a polymer of acrylic acid and one to three acrylate and / or methacrylate monomers. According to a preferred embodiment of the invention, polymer B is a polymer of acrylic acid and one to three alkyl acrylate and / or alkyl methacrylate monomers. According to a preferred embodiment of the invention, polymer B is a polymer of acrylic acid and one to three C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate monomers.

[0081] According to a more preferred embodiment, polymer B is a polymer of acrylic acid, butyl acrylate, butyl methacrylate, and methyl methacrylate. A suitable polymer B has CAS number 51981-89-6.

[0082] According to another embodiment, polymer B is an acrylic acid-acrylate copolymer, preferably an acrylic acid-C1-C6 alkyl acrylate copolymer.

[0083] Polymer B may be present in the water-based coating composition at a weight content of 1-30% by weight, preferably 5-25% by weight, more preferably 10-25% by weight, or even more preferably 15-25% by weight, based on the total dry weight of the coating composition.

[0084] Calcium carbonate materials

[0085] The aqueous coating composition according to the present invention comprises a calcium carbonate-containing material.

[0086] The calcium carbonate-containing material can be naturally ground calcium carbonate, precipitated calcium carbonate, or a mixture thereof.

[0087] In one embodiment, the calcium carbonate-containing material is precipitated calcium carbonate. As used herein, "precipitated calcium carbonate" (PCC) is a synthetic material, typically obtained by precipitation following the reaction of carbon dioxide with calcium hydroxide in an aqueous environment, or by precipitating calcium ions and carbonate ions (e.g., CaCl2 and Na2CO3) from solution. Other possible methods for producing PCC include the lime-soda process or the Solvay process, where PCC is a byproduct of ammonia production. Precipitated calcium carbonate exists in three primary crystal forms: calcite, aragonite, and aragonite, and for each of these forms, there are many different polymorphs (crystal inertia). Calcite has a triangular structure with typical crystal inertia such as subtrigonal (S-PCC), orthorhombic (R-PCC), hexagonal prism, axial, colloidal (C-PCC), cubic, and prismatic (P-PCC). Aragonite has an orthorhombic crystal structure, which exhibits typical crystal inertia of paired hexagonal prisms, as well as various classifications including slender prisms, curved leaf-like crystals, steep cones, chisel-shaped crystals, branched trees, and coral or worm-like forms. Spherulite belongs to the hexagonal crystal system. The obtained PCC slurry can be mechanically dehydrated and dried.

[0088] According to one embodiment, the precipitated calcium carbonate is a precipitated calcium carbonate that preferably contains aragonite, aragonite or calcite mineral crystals, or mixtures thereof.

[0089] In a preferred embodiment, the calcium carbonate-containing material is naturally ground calcium carbonate. Preferably, the naturally ground calcium carbonate is selected from chalk, limestone, marble, dolomite, and mixtures thereof. In another preferred embodiment, the naturally ground calcium carbonate is selected from chalk, limestone, or marble. More preferably, the naturally ground calcium carbonate is limestone or marble, and most preferably marble.

[0090] Naturally ground calcium carbonate can be obtained, for example, from natural calcium carbonate minerals (e.g., chalk, limestone, marble, or dolomite) in wet and / or dry pulverization steps (such as crushing and / or grinding). According to one embodiment, the naturally ground calcium carbonate is wet naturally ground calcium carbonate. In another embodiment, the naturally ground calcium carbonate is dry naturally ground calcium carbonate.

[0091] Naturally ground calcium carbonate can be obtained, for example, from natural calcium carbonate minerals (e.g., chalk, limestone, marble, or dolomite) through wet and / or dry pulverization steps (such as crushing and / or grinding). According to one embodiment, the naturally ground calcium carbonate is naturally wet-ground calcium carbonate. In another embodiment, the naturally ground calcium carbonate is naturally dry-ground calcium carbonate.

[0092] This grinding step can be carried out, for example, with any conventional grinding apparatus under conditions where refinement is primarily achieved by the impact of an auxiliary body, i.e., in one or more of the following: ball mill, rod mill, vibratory mill, crusher, centrifugal impact mill, vertical bead mill, grinder, pin pulverizer, hammer mill, powder mill, shredder, de-clumping machine, knife cutter, or other such equipment known to those skilled in the art. This grinding step can also be carried out under conditions that cause self-grinding to occur and / or by horizontal ball milling and / or other such methods known to those skilled in the art.

[0093] In one embodiment, grinding is carried out in a vertical or horizontal ball mill, preferably in a vertical ball mill. Such vertical and horizontal ball mills typically consist of a cylindrical grinding chamber arranged vertically or horizontally, which includes an axially rapidly rotating agitator shaft equipped with multiple blades and / or stirring discs, as described, for example, in EP0607840 A1.

[0094] It should be noted that the grinding of the calcium carbonate mineral can be carried out using at least one of the grinding methods or apparatuses described above. However, any combination of the aforementioned methods or a series of the aforementioned grinding apparatuses may also be used.

[0095] Following this grinding step, the ground calcium carbonate mineral may optionally be separated into two or more fractions, each with a different particle distribution, using a classification step. The classification step is typically used to separate a feed fraction with a given particle size distribution into coarse and fine fractions. The coarse fraction may undergo another grinding cycle, while the fine fraction may be used as the final product. For this purpose, screening devices and gravity-based devices, such as centrifuges or cyclones (e.g., hydrocyclones), and any combination thereof can be used.

[0096] According to one embodiment, the calcium carbonate-containing material has a calcium carbonate content of at least 75% by weight, preferably at least 90% by weight, and most preferably at least 95% by weight based on the total weight of the calcium carbonate-containing material. According to a preferred embodiment, the calcium carbonate-containing material is naturally ground calcium carbonate (e.g., obtained from marble), having a calcium carbonate content of at least 75% by weight, preferably at least 90% by weight, and most preferably at least 95% by weight based on the total weight of the calcium carbonate-containing material.

[0097] The calcium carbonate-containing material is preferably characterized by a specific particle size. According to one embodiment of the invention, the calcium carbonate-containing material has a median weight particle size d. 50 The micrometer range is 0.1-15 micrometers, preferably 0.1-5 micrometers, and more preferably 0.1-3 micrometers.

[0098] According to one embodiment of the present invention, the calcium carbonate-containing material has a top-cut weight particle size d 98 The micrometer range is 0.5-30 micrometers, preferably 0.5-20 micrometers, and more preferably 0.5-15 micrometers.

[0099] According to a preferred embodiment, the calcium carbonate-containing material has a median particle size d. 50 The particle size is 0.1-15 micrometers, preferably 0.1-5 micrometers, more preferably 0.1-3 micrometers, and even more preferably 0.1-1.5 micrometers, and the top-cut weight particle size d 98 The micrometer range is 0.5-30 micrometers, preferably 0.5-20 micrometers, more preferably 0.5-15 micrometers, and even more preferably 0.5-5 micrometers.

[0100] According to a preferred embodiment, the calcium carbonate is naturally ground calcium carbonate, preferably obtained from marble, having a calcium carbonate content of at least 90% by weight, preferably at least 95% by weight, based on the total weight of the calcium carbonate-containing material, and having a median particle size d. 50 The particle size is 0.1-15 micrometers, preferably 0.1-5 micrometers, more preferably 0.1-3 micrometers, and even more preferably 0.1-1.5 micrometers, and the top-cut weight particle size d 98The micrometer range is 0.5-30 micrometers, preferably 0.5-20 micrometers, more preferably 0.5-15 micrometers, and even more preferably 0.5-5 micrometers.

[0101] According to one embodiment, the calcium carbonate-containing material has a median particle size d. 50 The particle size is 0.1 micrometers to less than 0.8 micrometers, more preferably 0.1 micrometers to less than 0.5 micrometers, and / or the top-cut weight particle size d. 98 The particle size is from 0.5 micrometers to less than 4 micrometers, preferably 0.5-1.5 micrometers (e.g., 0.5-1.0 micrometers). According to one embodiment, the calcium carbonate-containing material has a median weight particle size d. 50 The particle size is 0.1 micrometers to less than 0.8 micrometers, more preferably 0.1 micrometers to less than 0.5 micrometers, and the top-cut weight particle size d 98 The particle size is 0.5 micrometers to less than 4 micrometers, preferably 0.5-1.5 micrometers (e.g., 0.5-1.0 micrometers). According to a preferred embodiment, the calcium carbonate-containing material has (i) a calcium carbonate content of at least 90% by weight, preferably at least 95% by weight, based on the total weight of the calcium carbonate-containing material, and (ii) a median particle size d. 50 (iii) Top-cut weight particle size d 98 The micron value is 0.5 micrometers to less than 4 micrometers, preferably 0.5-1.5 micrometers (e.g. 0.5-1.0 micrometers), and (iv) is natural ground calcium carbonate, preferably obtained from marble.

[0102] The inventors have surprisingly discovered that the particle size of the calcium carbonate-containing material in the coating composition of the present invention affects the heat-sealing capability of the coated article. The finer the particle size of the material, the lower the temperature at which a very good heat seal can be achieved. The low temperature required to achieve a good heat seal is advantageous in terms of the energy efficiency and processability of heat sealing machines (e.g., hot air heat sealing machines), which typically operate at the upper limit of the possible heat-sealing temperature.

[0103] This calcium carbonate-containing material can also be characterized by its specific surface area. The term "specific surface area" (in m²) is used throughout this document for all materials. 2 The total surface area (in m²) of the material can be determined by the Brunauer-Emmett-Teller (BET) method using nitrogen as the adsorbed gas and by using a Micromeritics ASAP 2460 instrument. This method is well known to those skilled in the art and is defined in ISO 9277:2010. Prior to such measurements, the sample can be filtered in a Brunauer-Emmett-Teller funnel, rinsed with deionized water, and dried in an oven at 110°C for at least 12 hours. 2(Indicated) can be expressed by the specific surface area of ​​the material (in m²) 2 It is obtained by multiplying the mass (in g) by the mass (in g).

[0104] According to one embodiment, the calcium carbonate-containing material has a specific surface area of ​​0.5 m², measured using nitrogen and the BET method. 2 / g to 40m 2 / g, preferably 0.5m 2 / g to 30m 2 / g, more preferably 2m 2 / g to 20m 2 / g, or even more preferably 10-20m 2 / g.

[0105] The calcium carbonate-containing material is present in the aqueous coating composition at a weight content of 0.1% to less than 20% based on the total dry weight of the coating composition. According to a preferred embodiment of the invention, the aqueous coating composition comprises the calcium carbonate-containing material in an amount of 0.1-12.5% ​​by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight (e.g., 3-8% by weight or 5-8% by weight) based on the total dry weight of the coating composition.

[0106] Those skilled in the art know how to determine the "total dry weight" of an aqueous coating composition. A method for determining the "total dry weight" of an aqueous composition is described in the Examples section.

[0107] The inventors have discovered that adding a calcium carbonate-containing material in an amount from 0.1% by weight to less than 20% by weight improves the hot water stability of articles coated with the coating composition of the present invention. When the content of this calcium carbonate-containing material in the composition increases to 20% by weight or higher, the heat-sealing capability of the coated article may decrease to an unacceptable level. For example, a content of this material of less than or equal to 12.5% ​​by weight or less than or equal to 8% by weight results in very good hot water stability of the coating while achieving a relatively low hot air sealing temperature. In this case, excellent sealing capability can even be achieved below 500°C, which is advantageous, for example, in terms of energy efficiency, and in order to not exceed the maximum sealing temperature of certain cup machines.

[0108] Wax (optional)

[0109] The water-based coating composition optionally contains wax.

[0110] The wax can be selected from plant waxes (such as carnauba wax, jojoba oil, candelilla wax, and crown palm wax), animal waxes (such as wool wax, beeswax, or china wax), hydrocarbon waxes, and mixtures thereof.

[0111] Preferably, the wax is a hydrocarbon wax, and most preferably, the wax is paraffin or a polyolefin wax (e.g., polyethylene wax).

[0112] Most preferably, the wax is paraffin. As used in this invention, "paraffin" refers to a compound derived from petroleum, coal, or shale oil, composed of a mixture of hydrocarbons (preferably containing 20-40 carbon atoms), solid at 25°C, and beginning to melt at a temperature ranging from 40-90°C, preferably 60-80°C. A suitable paraffin is that with CAS number 8002-74-2.

[0113] The wax may be present in the water-based coating composition at a weight content of 0.1-15% by weight, preferably 1-15% by weight, more preferably 1-11% by weight, even more preferably 3-11% by weight, even more preferably 5-11% by weight, and even more preferably 7-11% by weight, based on the total dry weight of the coating composition.

[0114] Additives (optional)

[0115] The aqueous coating composition according to the invention optionally includes one or more additives selected from acids, bases, rheology modifiers, viscosity enhancers, defoamers, biocides, tension surface modifiers, and dispersants.

[0116] The one or more additives may be present in the water-based coating composition at a weight content of 0.01-5.0% by weight, preferably 0.01-4.0% by weight, more preferably 0.1-4.0% by weight, based on the total dry weight of the composition.

[0117] The list of additives provided here is not exhaustive. Those skilled in the art may select and add additional additives if necessary.

[0118] Coating composition

[0119] In one aspect, the present invention relates to an aqueous coating composition comprising...

[0120] (a) Polymer A, comprising units derived from α-olefins and one or more comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0121] (b) Polymer B, comprising units derived from one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts;

[0122] (c) A calcium carbonate-containing material comprising 0.1% to less than 20% by weight of the total dry weight of the coating composition; and

[0123] (d)Optional, wax.

[0124] For preferred embodiments of polymer A, polymer B, the calcium carbonate-containing material, optional wax, and optional additives, please refer to the sections above.

[0125] The statement “the waterborne coating composition comprises (c) a calcium carbonate-containing material in an amount of 0.1% by weight to less than 20% by weight based on the total dry weight of the coating composition” should be understood as: the waterborne coating composition comprises a calcium carbonate-containing material, wherein the calcium carbonate-containing material is present in the waterborne coating composition in an amount of 0.1% by weight to less than 20% by weight based on the total dry weight of the coating composition.

[0126] The coating composition of the present invention contains water. In addition to water, the aqueous coating composition may also contain one or more other fluid media, such as organic solvents. However, preferably, the coating composition contains only water as a liquid medium.

[0127] The aqueous coating composition typically comprises polymer A and polymer B in a specific weight ratio relative to each other. According to a preferred embodiment of the invention, the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 50:50 to 99:1 (e.g., >50:<50 to 99:1), preferably >65:<35 to 99:1, more preferably 70:30 to 99:1, and most preferably 75:25 to 95:5.

[0128] The inventors have discovered that using a specific weight ratio of polymer A to polymer B can further improve the hot water stability of coated products (reduce the COBB value of hot water).

[0129] Furthermore, the aqueous coating composition typically contains a specific combined amount of polymer A and polymer B. According to a preferred embodiment of the invention, the aqueous coating composition contains a combined amount of polymer A and polymer B of 60-99.9% by weight, preferably 75-99.9% by weight, more preferably 85-95% by weight, and even more preferably 90-95% by weight, based on the total dry weight of the coating composition.

[0130] This aqueous coating composition typically comprises mandatory and optional components in specific weight amounts based on the total dry weight of the coating composition. Those skilled in the art will readily select the specific weight amounts of the mandatory and optional components such that they add up to 100% by weight. Preferably, the indicated weight amounts of the mandatory and optional components are selected to add up to 100% by weight.

[0131] According to a preferred embodiment of the invention, the aqueous coating composition comprises, based on the total weight of the coating composition:

[0132] (a) Polymer A comprising 55-98% by weight, preferably 60-85% by weight, more preferably 60-80% by weight, and even more preferably 60-70% by weight.

[0133] (b) 1-30% by weight, preferably 5-25% by weight, more preferably 10-25% by weight, and even more preferably 15-25% by weight of polymer B,

[0134] (c) 0.5% by weight to less than 20% by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight, and even more preferably 5-8% by weight of calcium carbonate-containing materials, and

[0135] (d) Optionally, 0.1-15% by weight, preferably 1-11% by weight, more preferably 7-11% by weight of wax.

[0136] According to a preferred embodiment of the invention, the aqueous coating composition comprises, based on the total weight of the coating composition:

[0137] (a) Polymer A comprising 55-98% by weight, preferably 60-85% by weight, more preferably 60-80% by weight, and even more preferably 60-70% by weight.

[0138] (b) 1-30% by weight, preferably 5-25% by weight, more preferably 10-25% by weight, and even more preferably 15-25% by weight of polymer B,

[0139] (c) 0.5% by weight to less than 20% by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight, and even more preferably 5-8% by weight of calcium carbonate-containing materials, and

[0140] (d) 0.1-15% by weight, preferably 1-11% by weight, or even more preferably 7-11% by weight of wax.

[0141] According to a preferred embodiment of the invention, the aqueous coating composition comprises, based on the total weight of the coating composition:

[0142] (a) Polymer A comprising 55-98% by weight, preferably 60-85% by weight, more preferably 60-80% by weight, and even more preferably 60-70% by weight.

[0143] (b) 1-30% by weight, preferably 5-25% by weight, more preferably 10-25% by weight, and even more preferably 15-25% by weight of polymer B,

[0144] (c) 0.5% by weight to less than 20% by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight, and even more preferably 5-8% by weight of calcium carbonate-containing materials, and

[0145] (d) 0.1-15% by weight, preferably 1-11% by weight, or even more preferably 7-11% by weight of wax.

[0146] (e) Optionally, 0.01-5.0% by weight, preferably 0.01-4.0% by weight, more preferably 0.1-4.0% by weight of the additive.

[0147] According to a preferred embodiment of the invention, the aqueous coating composition comprises, based on the total weight of the coating composition:

[0148] (a) Polymer A comprising 55-98% by weight, preferably 60-85% by weight, more preferably 60-80% by weight, and even more preferably 60-70% by weight.

[0149] (b) 1-30% by weight, preferably 5-25% by weight, more preferably 10-25% by weight, and even more preferably 15-25% by weight of polymer B,

[0150] (c) 0.5% by weight to less than 20% by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight, and even more preferably 5-8% by weight of calcium carbonate-containing materials, and

[0151] (d) 0.1-15% by weight, preferably 1-11% by weight, or even more preferably 7-11% by weight of wax.

[0152] (e) 0.01-5.0% by weight, preferably 0.01-4.0% by weight, more preferably 0.1-4.0% by weight of additives.

[0153] According to a preferred embodiment, the aqueous coating composition comprises, based on the total weight of the coating composition:

[0154] (a) 60-70% by weight of polymer A,

[0155] (b) 15-25% by weight of polymer B,

[0156] (c) 5-8% by weight of calcium carbonate-containing materials,

[0157] (d) 7-11% by weight of wax; and

[0158] (e) 0.1-4.0% by weight of additives.

[0159] This waterborne coating composition typically contains mandatory and optional components in specific weight percentages (dry weight parts) relative to each other.

[0160] According to one embodiment of the present invention, the aqueous coating composition comprises:

[0161] (a) 50-99, preferably >65 to 95, more preferably 70-95 parts by weight of polymer A.

[0162] (b) 1-50, preferably 5 to <35, more preferably 5-25 parts by weight of polymer B,

[0163] (c) 1 to <20, preferably 1-15, more preferably 2-9 parts by weight of calcium carbonate-containing material, and

[0164] (d) Optionally, 1-15, preferably 5-12, more preferably 7-12 parts by weight of wax.

[0165] According to one embodiment of the present invention, the aqueous coating composition comprises:

[0166] (a) 50-99, preferably >65 to 95, more preferably 70-95 parts by weight of polymer A.

[0167] (b) 1-50, preferably 5 to <35, more preferably 5-25 parts by weight of polymer B,

[0168] (c) 1 to <20, preferably 1-15, more preferably 2-9 parts by weight of calcium carbonate-containing material, and

[0169] (d) 1-15 parts by weight of wax, preferably 5-12 parts by weight, more preferably 7-12 parts by weight.

[0170] According to one embodiment of the present invention, the aqueous coating composition comprises:

[0171] (a) 50-99, preferably >65 to 95, more preferably 70-95 parts by weight of polymer A.

[0172] (b) 1-50, preferably 5 to <35, more preferably 5-25 parts by weight of polymer B,

[0173] (c) 1 to <20, preferably 1-15, more preferably 2-9 parts by weight of calcium carbonate-containing material,

[0174] (d) 1-15 parts by weight of wax, preferably 5-12 parts by weight, more preferably 7-12 parts by weight, and

[0175] (e) Optionally, 0.01-7.5, preferably 0.1-5 parts by weight of the additive.

[0176] According to one embodiment of the present invention, the aqueous coating composition comprises:

[0177] (a) 50-99, preferably >65 to 95, more preferably 70-95 parts by weight of polymer A.

[0178] (b) 1-50, preferably 5 to <35, more preferably 5-25 parts by weight of polymer B,

[0179] (c) 1 to <20, preferably 1-15, more preferably 2-9 parts by weight of calcium carbonate-containing material,

[0180] (d) 1-15 parts by weight of wax, preferably 5-12 parts by weight, more preferably 7-12 parts by weight, and

[0181] (e) 0.01-7.5, preferably 0.1-5 parts by weight of additives.

[0182] According to one embodiment, the aqueous coating composition comprises:

[0183] (a) 70-95 parts by weight of polymer A,

[0184] (b) 5-25 parts by weight of polymer B,

[0185] (c) 2-9 parts by weight of calcium carbonate-containing material,

[0186] (d) 7-12 parts by weight of wax, and

[0187] (e) 0.1-5 parts by weight of additives.

[0188] The aqueous coating composition according to the present invention may have specific solids content, pH value and / or viscosity.

[0189] According to one embodiment, the water-based coating composition has a solids content of 5-70% by weight, preferably 20-60% by weight, and more preferably 30-50% by weight.

[0190] According to one embodiment, the aqueous coating composition has a pH value of 7.5-12, preferably 8-11, more preferably 8-9.5 (e.g. 8.0-9.0).

[0191] The aqueous coating composition may have a viscosity of 25-2000 mPa*s (at 100 rpm) according to ISO 1652:2011. This viscosity may depend on the amount of calcium carbonate-containing material present in the composition. According to one embodiment, the aqueous coating composition has a viscosity of 25-500 mPa*s, for example 35-100 mPa*s (at 100 rpm), according to ISO 1652:2011.

[0192] According to one embodiment, the aqueous coating composition has a solids content of 5-70% by weight, preferably 20-60% by weight, more preferably 30-50% by weight, and a pH value of 7.5-12, preferably 8-11, more preferably 8-9.5, and most preferably 8-9. According to another embodiment, the aqueous coating composition has a solids content of 5-70% by weight, preferably 20-60% by weight, more preferably 30-50% by weight, and a pH value of 7.5-12, preferably 8-11, more preferably 8-9.5 (e.g., 8.0-9.0), and a viscosity of 25-500 mPa*s (e.g., 35-100 mPa*s) according to ISO 1652:2011.

[0193] According to a preferred embodiment, the aqueous coating composition includes a dispersant as an additive. This dispersant can be used to disperse the calcium carbonate-containing material in the composition.

[0194] The aqueous coating compositions defined herein can be obtained by or can be obtained by a method including the following steps:

[0195] Provides an aqueous composition I, preferably an aqueous dispersion, comprising polymer A and a preferred wax.

[0196] Provided is an aqueous composition II, preferably an aqueous dispersion, comprising polymer B and a preferred wax.

[0197] Provide materials containing calcium carbonate.

[0198] Mix the aqueous compositions I and II with the calcium carbonate-containing material.

[0199] The mixing steps can be performed in any order. However, it is preferable to first mix aqueous compositions I and II containing polymers A and B, and then add the calcium carbonate-containing material.

[0200] In a preferred embodiment, the aqueous composition I is an aqueous dispersion of polymer A and wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 35-50% by weight (e.g., about 39.5% by weight).

[0201] In a preferred embodiment, the aqueous composition II is an aqueous dispersion comprising polymer B and wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 45-55% by weight (e.g., about 50.5% by weight).

[0202] The calcium carbonate-containing material can be provided in solid or liquid form. Preferably, the calcium carbonate-containing material is provided in liquid form, more preferably as an aqueous composition. Therefore, the aqueous coating composition defined herein can be obtained by or can be obtained by a method comprising the following steps:

[0203] Provides an aqueous composition I, preferably an aqueous dispersion, comprising polymer A and a preferred wax.

[0204] Provided is an aqueous composition II, preferably an aqueous dispersion, comprising polymer B and a preferred wax.

[0205] Provides an aqueous composition III containing the calcium carbonate material,

[0206] Aqueous compositions I through III are mixed in any order, but preferably aqueous compositions I and II are mixed, and then aqueous composition III is added.

[0207] In a preferred embodiment, the calcium carbonate-containing material is provided in the form of an aqueous composition III, which is an aqueous suspension containing the calcium carbonate-containing material, wherein the suspension has a solids content of 1-85% by weight, preferably 50-85% by weight. Preferably, the calcium carbonate-containing material is dispersed by a dispersant.

[0208] According to a preferred embodiment, the aqueous coating composition can be obtained by a method comprising the following steps or by a method comprising the following steps:

[0209] An aqueous composition I is provided, comprising an aqueous dispersion of polymer A and a wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 35-50% by weight (e.g., about 39.5% by weight).

[0210] Provided is an aqueous composition II, comprising an aqueous dispersion of polymer B and a wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 45-55% by weight (e.g., about 50.5% by weight).

[0211] Aqueous composition III is provided, comprising an aqueous suspension containing the calcium carbonate material, wherein the suspension has a solids content of 1-85% by weight, preferably 50-85% by weight.

[0212] Mix aqueous compositions I and II, then add aqueous composition III.

[0213] Optionally, this is followed by one or more steps selected from adjusting the pH, adjusting the viscosity, and adding additives.

[0214] The additive may be added to any one of the aqueous compositions I to III and / or to the composition obtained by mixing aqueous compositions I to III.

[0215] Method for preparing coating compositions

[0216] Another aspect of the invention relates to a method for preparing an aqueous coating composition according to the invention. The method comprises the following steps:

[0217] Provides an aqueous composition I comprising polymer A as defined herein and optionally a wax as defined herein.

[0218] Provides an aqueous composition II comprising polymer B as defined herein and optionally a wax as defined herein.

[0219] Provide the calcium carbonate-containing materials as defined in this article.

[0220] The mixed aqueous compositions I and II, and the calcium carbonate-containing material.

[0221] Those skilled in the art can select the conditions or equipment for mixing aqueous compositions I through III (and optional additives) according to their needs. Preferred embodiments of polymer A, polymer B, calcium carbonate-containing materials, optional waxes, and optional additives can be found in the preceding sections. The additives defined herein can be added to any one of aqueous compositions I through III and / or to compositions obtained by mixing aqueous compositions I through III.

[0222] The mixing steps can be performed in any order. However, it is preferable to first mix aqueous compositions I and II containing polymers A and B, and then add the calcium carbonate-containing material.

[0223] In a preferred embodiment, the aqueous composition I is an aqueous dispersion of polymer A and wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 35-50% by weight (e.g., about 39.5% by weight).

[0224] In a preferred embodiment, the aqueous composition II is an aqueous dispersion comprising polymer B and wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 45-55% by weight (e.g., about 50.5% by weight).

[0225] The calcium carbonate-containing material can be provided in solid or liquid form. Preferably, the calcium carbonate-containing material is provided in liquid form, more preferably as an aqueous composition, and even more preferably as a slurry. Slurries containing calcium carbonate materials are well known. Preferably, the calcium carbonate-containing material is dispersed by a dispersant.

[0226] Therefore, the method according to the present invention may include the following steps:

[0227] Provides an aqueous composition I, preferably an aqueous dispersion, comprising polymer A and a preferred wax.

[0228] Provided is an aqueous composition II, preferably an aqueous dispersion, comprising polymer B and a preferred wax.

[0229] Provides an aqueous composition III containing the calcium carbonate material,

[0230] Aqueous compositions I through III are mixed in any order, but preferably aqueous compositions I and II are mixed, and then aqueous composition III is added.

[0231] In a preferred embodiment, the calcium carbonate-containing material is provided in the form of an aqueous composition III, which is an aqueous suspension containing the calcium carbonate-containing material, wherein the suspension has a solids content of 1-85% by weight, preferably 50-85% by weight. Preferably, the calcium carbonate-containing material is dispersed by a dispersant.

[0232] According to a preferred embodiment, the method includes the following steps:

[0233] An aqueous composition I is provided, comprising an aqueous dispersion of polymer A and a wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 35-50% by weight (e.g., about 39.5% by weight).

[0234] Provided is an aqueous composition II, comprising an aqueous dispersion of polymer B and a wax in a weight ratio of 98:2 to 80:20, preferably 95:5 to 85:15 (e.g., about 90:10), wherein the dispersion has a solids content of 30-60% by weight, preferably 45-55% by weight (e.g., about 50.5% by weight).

[0235] Aqueous composition III is provided, which is: an aqueous suspension comprising a calcium carbonate material, wherein the suspension has a solids content of 1-85% by weight, preferably 50-85% by weight.

[0236] Mix aqueous compositions I and II, then add aqueous composition III.

[0237] Optionally, this is followed by one or more steps selected from adjusting the pH, adjusting the viscosity, and adding additives.

[0238] The additive may be added to any one of the aqueous compositions I to III and / or to the composition obtained by mixing aqueous compositions I to III.

[0239] Coated products

[0240] In another aspect, the present invention relates to a coated article comprising a substrate, wherein at least one surface of the substrate comprises a coating prepared by an aqueous coating composition according to the invention.

[0241] Those skilled in the art know how to prepare a coating from the aqueous coating composition of the present invention. The coating can be prepared by applying the aqueous coating composition to at least one surface of the substrate and drying the aqueous coating composition or by allowing the aqueous coating composition to dry.

[0242] The coating process can be performed by bar coating, blade coating, curtain coating, or by printing techniques such as flexographic or offset printing. These methods are known in the art. Bar coating, as a preferred coating method, is also described in the embodiments.

[0243] The drying step can be performed by hot air, air jet, and / or IR drying. Such methods are also known in the art.

[0244] There are no particular limitations on the substrate. The substrate can be a plastic suitable for the packaging industry, such as, but not limited to, polyolefins (e.g., PE, PP, polystyrene), polyesters (e.g., PET, PLA), and mixtures thereof. The substrate can be a metal such as aluminum (e.g., aluminum foil). According to one embodiment, the substrate is a plastic (preferably polyolefin, polyester, polystyrene, or mixtures thereof), a metal (preferably aluminum), or a cellulose-based substrate. Preferably, the substrate is a cellulose-based substrate. Suitable cellulose-based substrates are, for example, high-grade paper, paper, recycled paper, cardboard, corrugated cardboard, card stock, wallpaper, photographic paper, or tissue paper. The cellulose-based substrate is not limited to a specific shape or form. The cellulose-based substrate can be die-cut and / or cut into specific geometries, etc.

[0245] According to a preferred embodiment of the present invention, the substrate is a cellulose-based substrate, preferably paper, paperboard or pallet.

[0246] The cellulose-based substrate (preferably paper, paperboard, or pallet) can have a basis weight of 15-500 g / m³. 2 More preferably 50-400g / m 2 The optimal value is 100-350g / m³. 2 .

[0247] The coated article may include a pre-coating between the coating and at least one surface of the substrate (preferably a cellulose-based substrate, more preferably paper, paperboard, or pallet). The pre-coating may be calendered. The pre-coating may contain at least one mineral and a binder (e.g., latex).

[0248] The at least one mineral may be selected from kaolin, clay, dolomite, mica, calcium carbonate, talc, and mixtures thereof. According to one embodiment, the pre-coating comprises calcium carbonate. It may sometimes be preferred that calcium carbonate is the only mineral in the pre-coating. Therefore, in one embodiment, the pre-coating comprises one mineral, which is calcium carbonate. However, a mineral mixture, for example, comprising calcium carbonate and at least one other mineral, may also be used. For example, a mineral mixture of calcium carbonate and talc may be used in the pre-coating composition. For example, the mineral mixture may be calcium carbonate and talc in a weight ratio of 60:40 to 20:80, preferably 60:40 to 40:60 (e.g., about 50:50).

[0249] The pre-coating may include

[0250] 20-60, preferably 40-60 (e.g., about 50) parts by weight of calcium carbonate,

[0251] 40-80, preferably 40-60 (e.g., about 50) parts by weight of talc.

[0252] 2-20, preferably 5-15 (e.g., about 10) parts by weight of adhesive (e.g., latex),

[0253] And 0.01-1 parts by weight of additives, preferably rheology modifiers.

[0254] The pre-coating can have a strength of 1-20 g / m². 2 Preferred concentration: 2-15g / m 2 More preferably 3-12g / m 2 The weight of the coating.

[0255] According to one embodiment, the coated article comprises a coating prepared from an aqueous coating composition according to the invention on at least one surface of the substrate, the amount of which is 1-20 g / m². 2 Preferred concentration: 2-15g / m 2 More preferably 5-15g / m 2 The optimal value is 5-13 g / m³. 2 .

[0256] It has been found that this water-based coating composition, or its dried form, can be used at relatively low weight concentrations while still providing very good results in terms of barrier properties and sealing capabilities. In addition to requiring fewer resources for production, the low amount of heat-sealable coating is particularly advantageous for recycling the coated article in subsequent stages.

[0257] Another aspect of the invention relates to a method for preparing a coated article according to the invention. The method preferably includes the following steps:

[0258] Provide a substrate having at least one surface.

[0259] Provides the aqueous coating compositions defined herein,

[0260] The aqueous coating composition is applied to at least one surface of the substrate.

[0261] Dry the water-based coating composition or allow the water-based coating composition to dry.

[0262] The coating process can be performed by bar coating, blade coating, curtain coating, or by printing techniques such as flexographic or offset printing. Such methods are known in the art.

[0263] The drying step can be performed by hot air, air jet, and / or IR drying. Such methods are known in the art.

[0264] Other implementation methods disclosed herein are defined by the following terms:

[0265] [1] An aqueous coating composition, comprising

[0266] (a) Polymer A, comprising units derived from α-olefins and one or more comonomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts.

[0267] (b) Polymer B, comprising units derived from one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, maleic esters, maleic acid, maleic anhydride and their salts;

[0268] (c) A calcium carbonate-containing material comprising 0.1% to less than 20% by weight of the total dry weight of the coating composition; and

[0269] (d)Optional, wax.

[0270] [2] The aqueous coating composition according to [1], wherein the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 50:50 to 99:1, preferably >65:<35 to 99:1, more preferably 70:30 to 99:1, and most preferably 75:25 to 95:5.

[0271] [3] The aqueous coating composition according to [1] or [2], wherein the aqueous coating composition comprises a combination of polymers A and B in an amount of 60-99.9% by weight, preferably 75-99.9% by weight, more preferably 85-95% by weight, based on the total dry weight of the coating composition.

[0272] [4] The aqueous coating composition according to any one of [1]-[3], wherein the aqueous coating composition comprises 0.1-12.5% ​​by weight, preferably 2-12.5% ​​by weight, more preferably 2-8% by weight of the calcium carbonate-containing material based on the total dry weight of the coating composition, and / or

[0273] The calcium carbonate-containing material has a calcium carbonate content of at least 90% by weight, preferably at least 95% by weight, based on the total weight of the calcium carbonate-containing material.

[0274] [5] The aqueous coating composition according to any one of [1] to [4], wherein the aqueous coating composition comprises:

[0275] (a) 50 to 99, preferably >65 to 95, more preferably 70 to 95 parts by weight of polymer A.

[0276] (b) 1 to 50, preferably 5 to <35, more preferably 5 to 25 parts by weight of polymer B,

[0277] (c) 1 to <20, preferably 1 to 15, more preferably 2 to 9 parts by weight of the calcium carbonate-containing material, and

[0278] (d) Optionally, 1 to 15, preferably 5 to 12, more preferably 7 to 12 parts by weight of wax.

[0279] [6] The aqueous coating composition according to any one of [1]-[5], wherein

[0280] Polymer A comprises, and preferably consists of, units derived from α-olefins, preferably ethylene, and one or more monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid and their salts, and / or

[0281] Polymer B comprises, and preferably consists of, a unit derived from one or more, preferably two to four, monomers selected from methacrylates, acrylates, methacrylic acid, acrylic acid, and their salts.

[0282] [7] The aqueous coating composition according to any one of [1]-[6], wherein

[0283] Polymer A is a copolymer of ethylene and acrylic acid, and / or polymer B is a polymer of acrylic acid and one to three C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate monomers.

[0284] [8] The aqueous coating composition according to any one of [1]-[7], wherein the polymer A has a comonomer content, preferably an acrylic acid content, of 0.5-25% mol, more preferably 15-25% mol.

[0285] Alternatively, polymer A may have a comonomer content, preferably an acrylic acid content, of 5-30% by weight, more preferably 10-25% by weight.

[0286] [9] The aqueous coating composition according to any one of [1]-[8], wherein

[0287] This calcium carbonate-containing material has a median particle size d. 50 The micrometer range is 0.1-15 micrometers, preferably 0.1-5 micrometers, more preferably 0.1 micrometers to less than 0.8 micrometers, and / or

[0288] This calcium carbonate-containing material has a top-cut weight particle size d 98 The micrometer range is 0.5-30 micrometers, preferably 0.5-20 micrometers, and more preferably 0.5 micrometers to less than 4 micrometers.

[0289]

[10] The aqueous coating composition according to any one of [1] to [9], wherein the wax is a hydrocarbon wax, preferably paraffin wax.

[0290]

[11] The aqueous coating composition according to any one of [1]-

[10] , wherein

[0291] The water-based coating composition has a solids content of 5-70% by weight, preferably 20-60% by weight, more preferably 30-50% by weight, and / or

[0292] The aqueous coating composition has a pH value of 7.5-12, preferably 8-11, and more preferably 8-9.5.

[0293]

[12] A method for preparing an aqueous coating composition according to any one of [1]-

[11] , comprising the following steps:

[0294] Provides an aqueous composition I comprising polymer A and optional wax,

[0295] Provides an aqueous composition II comprising polymer B and optional wax.

[0296] Provide materials containing calcium carbonate.

[0297] The aqueous compositions I and II are mixed with the calcium carbonate-containing material.

[0298]

[13] A coated article comprising a substrate, wherein at least one surface of the substrate comprises a coating prepared from an aqueous coating composition according to any one of [1]-

[11] .

[0299]

[14] The coated article according to

[13] , wherein the substrate is a cellulose-based substrate, plastic or metal, preferably a cellulose-based substrate, more preferably paper, paperboard or pallet.

[0300]

[15] The coated article according to

[13] or

[14] , wherein the coated article comprises a pre-coating layer between at least one surface of the substrate and the coating layer.

[0301] The pre-coating contains at least one mineral (preferably talc and / or calcium carbonate) and a binder. Detailed Implementation

[0302] The invention will be described below by way of specific embodiments. These embodiments should not be construed as limiting the invention in any way.

[0303] Example

[0304] 1. Methods and Instruments

[0305] Particle size distribution

[0306] In the experiment, the median weight particle size d was measured using a Sedigraph 5120 from Micromeritics Instrument Corporation, USA. 50 and weight top-cut particle size d 98 Values. The methods and instruments are known to those skilled in the art and are commonly used to determine the particle size of fillers and pigments. Measurements can be performed in an aqueous solution containing 0.1% by weight of Na₄P₂O₇. The sample can be dispersed using a high-speed stirrer and ultrasonic treatment. No additional dispersant is added for measurements of dispersed samples.

[0307] Solid content of water-based coating compositions

[0308] The solids content (also known as "dry weight") of the suspension was determined using a Moisture Analyzer MJ33 from Mettler-Toledo, Switzerland, with the following settings: drying temperature of 160°C, automatic shutdown if the mass changes by no more than 1 mg within 30 seconds, and standard drying of 5-20 g of suspension.

[0309] Water absorption determination

[0310] Cobb Unger (wl5) uses ISO 535:1991(E) for measurement. According to this method, the content of paper or board is measured in g / m³ under specified conditions over a period of 1800 seconds. 2 The measure of water absorbency is the mass of water absorbed within a specified time. The conditioning atmosphere follows ISO 187 (23°C / 50% RH). For the measurement of hot water absorbency, according to this method, the absorbance of paper or board is measured in g / m³ within 60 seconds under specified conditions. 2 The unit is the mass of water absorbed at 90°C within a specified time.

[0311] Preparation of water-based coating compositions

[0312] All mixing steps were performed using a Pendraaulik Laboratory Dissolver LD 50.

[0313] Coating of paper substrate

[0314] Using a Durrer continuous laboratory coating machine (Switzerland), rod metering (X23 (23 mL / m)) was employed. 2 The coating is applied at a coating speed of 20 m / min (with a bar pressure of approximately 1 bar and a bar rotation speed of 12 rpm). The pre-coating is applied using the same machine, but with the following doctor blade settings: 20 m / min, doctor blade thickness of 0.3 mm, and doctor blade pressure of 1 bar.

[0315] Hot air seal

[0316] Hot air seal tests were conducted at the Department of Materials Science and Environmental Engineering, Paper Processing and Packaging Technology, Tampere University (Finland). Hot air seal capability was measured at temperatures between 300 and 500°C, with sample dimensions of 105 mm MD x 155 mm CD (sealed area 105 mm x 3 mm). The sealing force was set to 400 N, the heat sealing time to 1.24 seconds, the compression time to 1.9 seconds, and the network pressure to 6 bar. Measurements were taken in triplicate to obtain optimal values, and the maximum machine temperature was 550°C.

[0317] The sealing is performed in the following ways: (1) sealing the coated surface of the substrate to the coated surface of the substrate (hot air seal AA: coated side - coated side), or (2) sealing the coated surface of the substrate to the uncoated (original) surface of the substrate (hot air seal AB: coated side - back side).

[0318] heat clamp seal

[0319] Heat clamp sealing was performed on a Kopp LaboratorySealer SGPE 3000 (Reichenbach, Germany) equipped with a 200x5mm sealing strip. The temperature was set within the range of 90-160°C, and the sealing force was 100N (0.4N / mm²). 2 The sealing time is 0.5 seconds.

[0320] Sealing strength

[0321] The seal strength of a heat-clamped seal was measured using an unsupported T-Peel test with an L&W tensile tester (Lorentzen & Wettre, Sweden) and a 50 mm wide test specimen. The seal strength at the point of fracture (peeling) is reported in Newtons [N].

[0322] 2. Materials

[0323] polymer

[0324] Polymer Mix 1:

[0325] A neutralized aqueous dispersion of an ethylene / acrylic acid polymer (Polymer A; CAS: 9010-77-9). Polymer A has an acrylic acid comonomer content of approximately 20% mol; a solids content of 40.0% by weight; a pH value (ISO 976-2013) of 8.5; and a viscosity (ISO 1652:2011) of 350 ± 200 mPa*s.

[0326] Polymer Mix 2:

[0327] A neutralized aqueous dispersion of acrylate / acrylic polymer (polymer B; CAS: 51981-89-6); solids content of 52.0% by weight; pH (ISO 976-2013) of 8.0; viscosity (ISO 1652:2011) of 250±100 mPa*s.

[0328] Polymer Mix 3:

[0329] An aqueous dispersion of 90% by weight (based on total dry solids) of neutralized ethylene / acrylic acid polymer (Polymer A; CAS: 9010-77-9) and 10% by weight (based on total dry solids) of paraffin; solids content 40.0% by weight; pH (ISO 976-2013) 8.5; viscosity (ISO 1652:2011) 350 ± 200 mPa*s. Polymer A has an acrylic acid comonomer content of approximately 20% molar.

[0330] Polymer Mix 4:

[0331] An aqueous dispersion of 90% by weight (based on total dry solids) of neutralized acrylate / acrylic polymer (polymer B; CAS: 51981-89-6) and 10% by weight (based on total dry solids) of paraffin; solids content of 51.0% by weight; pH (ISO 976-2013) of 8.0; viscosity (ISO 1652:2011) of 200±100 mPa*s.

[0332] Polymer Mix 5:

[0333] An aqueous dispersion of 90% by weight (based on total dry solids) of neutralized ethylene / acrylic acid polymer (Polymer A2; CAS: 9010-77-9) and 10% by weight (based on total dry solids) of paraffin; solids content 40.0% by weight; pH (ISO 976-2013) 8.5; viscosity (ISO 1652:2011) 350 ± 200 mPa*s. Polymer A2 contains approximately 10% molar of acrylic acid comonomer.

[0334] Calcium carbonate materials

[0335] CC1:

[0336] Naturally ground calcium carbonate (from Norwegian marble); median particle size d 50 =0.6μm; weight-based top-cut particle size d 98 =2.2μm; slurry with a solids content of 78% by weight; specific surface area (BET): 14.3m² 2 / g; available from OMYA, Switzerland.

[0337] CC2:

[0338] Naturally ground calcium carbonate (from Norwegian marble); median particle size d 50 =0.5μm; weight-based top-cut particle size d 98 =4μm; slurry with a solids content of 72% by weight; specific surface area (BET): 10.2m² 2 / g; available from OMYA, Switzerland.

[0339] CC3:

[0340] Naturally ground calcium carbonate (from Norwegian marble); median particle size d 50 =0.8μm; weight-based top-cut particle size d 98 =4μm; slurry with a solids content of 72% by weight; specific surface area (BET): 7.8m² 2 / g; available from OMYA, Switzerland.

[0341] CC4:

[0342] Naturally ground calcium carbonate (from Norwegian marble); median particle size d 50 =0.3μm; weight-based top-cut particle size d 99 =1μm; slurry with a solids content of 60% by weight; specific surface area (BET): 17.7m² 2 / g; available from OMYA, Switzerland.

[0343] CC5:

[0344] Naturally ground calcium carbonate (from Norwegian marble); median particle size d 50 =0.7μm; weight-based top-cut particle size d 98 =4μm; slurry with a solids content of 78% by weight; specific surface area (BET): 11.9m² 2 / g; available from OMYA, Switzerland.

[0345] Pre-coating formulation:

[0346] Pre1:

[0347] 30 parts by weight of calcium carbonate (CC5; 27.2% by weight, based on dry solids);

[0348] 70 parts by weight of talc (Finntalc C15-B2, commercially available from Elementis, Finland; 63.5% by weight, based on dry solids);

[0349] 10 parts by weight of binder (Litex PX 9460; 9.1% by weight, based on dry solids);

[0350] 0.2 parts by weight of rheology modifier (Rheocoat 35; purchased from Coatex, France; 0.2% by weight, based on dry solids).

[0351] Solid content: 61.1% by weight; pH value: 8.9; viscosity (at 100 rpm): 660 mPa*s.

[0352] Pre2:

[0353] 50 parts by weight of calcium carbonate (CC5; 45.4% by weight, based on dry solids);

[0354] 50 parts by weight of talc (Finntalc C15-B2, commercially available from Elementis, Finland; 45.4% by weight, based on dry solids);

[0355] 10 parts by weight of binder (Litex PX 9460; 9.1% by weight, based on dry solids);

[0356] 0.2 parts by weight of rheology modifier (Rheocoat 35, commercially available from Coatex, France; 0.2% by weight, based on dry solids).

[0357] Solid content: 61.1% by weight; pH value: 8.9; viscosity (at 100 rpm): 840 mPa*s.

[0358] Substrate:

[0359] Base paper:

[0360] Paper, 35 dark-spotted paper, white (WTL), purchased from Visy Industries Holdings Pty Ltd, Australia (weight: 184g / m2, thickness: 222μm, bulk: 1.20cm). 3 / g, density: 0.83g / cm³ 3 PPS: 4.91 μm, roughness (Bendtsen): 267 mL / min, air resistance (Gurley): 65.4 sec. / 100 cm 3 (Bendtsen air permeability: 173.7 mL / min).

[0361] Pre1 Paper:

[0362] Base paper coated with pre-coating formulation Pre1 (coating weight: 6.3 g / m²) 2 ).

[0363] Pre2 paper:

[0364] Base paper coated with pre-coating formulation Pre2 (coating weight: 6.4 g / m²) 2 ).

[0365] Pre-coated paper 3:

[0366] Pre-coated paper, 80 g / m2, product name "Sappi Magnostar", purchased from Sappi.

[0367]

[0368] The data in Table 1 show that paper substrates coated with the coating compositions IE1 to IE9 of the present invention have lower hot water absorption as determined by the hot water COBB test, compared to the comparative coating compositions CE1 and CE2 which do not contain calcium carbonate. The results indicate that the coatings of the present invention have better stability to hot water.

[0369] Table 2:

[0370] Example IE10 Paper substrate Pre-coated paper 3 <![CDATA[Water-based coating composition 1 > Polymer Mix 4 24 Polymer Mix 5 77 CC4 8 Solid content [%) 38 pH 9.5 Viscosity (@100rpm) 240 Coated paper <![CDATA[Coating weight (g / m 2 )]]> 10 <![CDATA[WVTR(23℃ / 50%RH / ;g / (m 2 *day))]]> 10.8 <![CDATA[COBB 1800(g / m 2 )]]> 12.1 <![CDATA[Hot water COBB (g / m 2 )]]> 15.6 <![CDATA[Hot air seal AA (℃) 2 > 270(5) <![CDATA[Hot air seal AB (°C) 2 > 360(5)

[0371] 1 Quantity is expressed in dry weight parts.

[0372] 2 Adhesion values ​​after sealing (in parentheses): 0 = no seal; 1 = weak adhesion; 2 = adhered but no fiber tear; 3 = less than 50% fiber tear; 4 = more than 50% fiber tear; 4.5 = more than 90% fiber tear; 5 = 100% fiber tear.

[0373] Table 3: Heat-clamp seal

[0374] Example seal 90℃ 100℃ 110℃ 120℃ 130℃ 140℃ 150℃ 160℃ IE10 AA 9.8N 10.1N 11.1N 11.4N 11.2N 7.3N 11.6N 9.7N IE10 AB 4.1N 4.0N 4.0N 3.6N 4.2N 4.6N 4.7N 4.0N

[0375] Table 3 shows the sealing test results of Example IE10 at the indicated temperature with a heat-clamp sealing time of 0.5 seconds. The force [N] reported in Table 3 represents the force required to break the seal.

Claims

1. An aqueous coating composition comprising (a) a polymer A consisting of units derived from ethylene and one or more comonomers selected from the group consisting of methacrylate, acrylate, methacrylic acid, acrylic acid, maleate, maleic acid, maleic anhydride, and salts thereof; (b) a polymer B consisting of units derived from one or more monomers selected from the group consisting of methacrylate, acrylate, methacrylic acid, acrylic acid, maleate, maleic acid, maleic anhydride, and salts thereof; (c) an amount of 0.1 weight-% to less than 20 weight-%, based on the total dry weight of the coating composition, of a calcium carbonate-comprising material, and wherein the calcium carbonate-comprising material has a weight median particle size d 50 of 0.1 - 15 micrometer and a top cut weight particle size d 98 of 0.5 - 30 micrometer; and (d) optionally, a wax.

2. The aqueous coating composition of claim 1, wherein the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 50:50 to 99:

1.

3. The aqueous coating composition of claim 2, wherein the aqueous coating composition comprises polymer A and polymer B in a weight ratio of >65:<35 to 99:

1.

4. The aqueous coating composition of claim 2, wherein the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 70:30 to 99:

1.

5. The aqueous coating composition of claim 2, wherein the aqueous coating composition comprises polymer A and polymer B in a weight ratio of 75:25 to 95:

5.

6. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises a combined amount of polymers A and B of 60-99.9% by weight based on the total dry weight of the coating composition.

7. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises a combined amount of polymers A and B of 75-99.9% by weight based on the total dry weight of the coating composition.

8. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises a combined amount of polymers A and B of 85-95% by weight based on the total dry weight of the coating composition.

9. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises the calcium carbonate-containing material in an amount of 0.1-12.5% by weight based on the total dry weight of the coating composition.

10. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises the calcium carbonate-containing material in an amount of 2-12.5% by weight based on the total dry weight of the coating composition.

11. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises the calcium carbonate-containing material in an amount of 2-8% by weight based on the total dry weight of the coating composition.

12. The aqueous coating composition of any one of claims 1-5, wherein the calcium carbonate-containing material has a calcium carbonate content of at least 90% by weight based on the total weight of the calcium carbonate-containing material.

13. The aqueous coating composition of any one of claims 1-5, wherein the calcium carbonate-containing material has a calcium carbonate content of at least 95% by weight based on the total weight of the calcium carbonate-containing material.

14. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises: (a) 50 to 99 parts by weight of the polymer A, (b) 1 to 50 parts by weight of the polymer B, (c) 1 to < 20 parts by weight of the calcium carbonate-containing material, and (d) optionally, 1 to 15 parts by weight of the wax.

15. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises: (a) > 65 to 95 parts by weight of the polymer A, (b) 5 to < 35 parts by weight of the polymer B, (c) 1 to 15 parts by weight of the calcium carbonate-containing material, and (d) 5 to 12 parts by weight of the wax.

16. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition comprises: (a) 70 to 95 parts by weight of the polymer A, (b) 5 to 25 parts by weight of the polymer B, (c) 2 to 9 parts by weight of the calcium carbonate-containing material, and (d) 7 to 12 parts by weight of the wax.

17. The aqueous coating composition of any one of claims 1-5, wherein polymer A consists of the following units: The units are derived from ethylene, and one or more monomers selected from the group consisting of methacrylate esters, acrylate esters, methacrylic acid, acrylic acid, and salts thereof.

18. The aqueous coating composition of any one of claims 1-5, wherein polymer B consists of the following units: The units are derived from one or more monomers selected from the group consisting of methacrylate esters, acrylate esters, methacrylic acid, acrylic acid, and salts thereof.

19. The aqueous coating composition of any one of claims 1-5, wherein polymer B consists of the following units: The units are derived from two to four monomers selected from the group consisting of methacrylate esters, acrylate esters, methacrylic acid, acrylic acid, and salts thereof.

20. The aqueous coating composition of any one of claims 1-5, wherein the polymer A is a copolymer of ethylene and acrylic acid.

21. The aqueous coating composition of any one of claims 1-5, wherein the polymer B is a polymer of acrylic acid and one to three C1-C6 alkyl acrylate and / or C1-C6 alkyl methacrylate monomers.

22. The aqueous coating composition of any one of claims 1-5, wherein the polymer A has a comonomer content of 0.5-25% mole.

23. The aqueous coating composition of any one of claims 1-5, wherein the polymer A has a comonomer content of 5-25% mole.

24. The aqueous coating composition of any one of claims 1-5, wherein the polymer A has an acrylic acid content of 0.5-25% mole.

25. The aqueous coating composition of any one of claims 1-5, wherein the polymer A has an acrylic acid content of 5-25% mole.

26. The aqueous coating composition of any one of claims 1-5, wherein The calcium carbonate-comprising material has a weight median particle size d 50 0.1 - 5 microns, and / or The calcium carbonate-comprising material has a top cut weight particle size d 98 of 0.5-20 microns.

27. The aqueous coating composition of any one of claims 1-5, wherein The calcium carbonate-comprising material has a weight median particle size d 50 from 0.1 microns to less than 0.8 microns, and / or The calcium carbonate-comprising material has a top cut weight particle size d 98 from 0.5 microns to less than 4 microns.

28. The aqueous coating composition of any one of claims 1-5, wherein the wax is a hydrocarbon wax.

29. The aqueous coating composition of any one of claims 1-5, wherein the wax is a paraffin wax.

30. The aqueous coating composition of any one of claims 1-5, wherein the aqueous coating composition has a solids content of 5-70% by weight, and / or the aqueous coating composition has a pH of 7.5-12.

31. The aqueous coating composition according to any one of claims 1-5, wherein the aqueous coating composition has a solids content of 20-60% by weight, and / or the aqueous coating composition has a pH value of 8-11.

32. The aqueous coating composition according to any one of claims 1-5, wherein the aqueous coating composition has a solids content of 30-50% by weight, and / or the aqueous coating composition has a pH value of 8-9.

5.

33. A method of preparing an aqueous coating composition according to any one of claims 1-32, comprising the steps of: providing an aqueous composition I comprising polymer A and optionally a wax, providing an aqueous composition II comprising polymer B and optionally a wax, providing a calcium carbonate-containing material, mixing the aqueous compositions I and II with the calcium carbonate-containing material.

34. A coated article comprising a substrate, wherein at least one surface of the substrate comprises a coating prepared from an aqueous coating composition according to any one of claims 1-32.

35. The coated article according to claim 34, wherein the substrate is a cellulose-based substrate, plastic or metal.

36. The coated article according to claim 34, wherein the substrate is a cellulose-based substrate.

37. The coated article according to claim 34, wherein the substrate is paper, paperboard or cardboard.

38. The coated article according to claim 34 or 35, wherein the coated article comprises a pre-coat layer between the at least one surface of the substrate and the coating, wherein the pre-coat layer comprises at least one mineral, and a binder.

39. The coated article according to claim 38, wherein the at least one mineral is talc and / or calcium carbonate.

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