Packaging material

Abstract

The invention relates to barrier paper comprising a substrate comprising or consisting of fibrous material and at least one coating film applied indirectly or directly on at least one side of the substrate, wherein the coating is obtained by indirect or direct application of a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles to the substrate and drying and film formation by heat input, characterized in that the polyolefin particles and / or polyolefin copolymer particles have at least one of the following particle size distributions: a) having a Span value of < 1.4, preferably < 1.0, particularly preferably < 0.6; b) a D 90 value of < 3.0 pm, preferably < 2.5 pm, particularly preferably < 2.0 pm; c) a D 50 value of < 1.5 pm, preferably < 1.0 pm, particularly preferably < 0.8 pm; a D10 value of < 0.8 pm, preferably < 0.7 pm, particularly preferably < 0.65 pm; a method for the production of such packaging material, the use of the packaging material as packaging or as a component part of packaging.

Description

Technical Field

[0001] This invention relates to packaging materials, methods for manufacturing such packaging materials, packaging materials obtained by such methods, and the use of such packaging materials as packaging or packaging components. Background Technology

[0002] Packaging generally refers to a covering or (partial or complete) covering of an object, especially for the purpose of protecting or better handling the object. Therefore, packaging materials include the materials that form such packaging.

[0003] Packaging materials can be constructed, for example, based on paper, plastic, and / or metal. This invention essentially relates to packaging materials based on paper, cardboard, and corrugated cardboard.

[0004] The primary requirements for packaging materials of any origin are to protect the packaged goods from external influences, prevent leakage, and function as advertising and information carriers. To this end, packaging materials should meet different standards depending on the packaged goods and the packaging process. Therefore, suitable packaging materials, in addition to so-called barrier properties against, for example, water, fats, oxygen, or mineral oils, should also meet mechanical and process-specific requirements. Packaging materials, especially flexible packaging materials, should possess sufficient tear strength, a suitable coefficient of friction, and flexibility depending on the packaging equipment. Packaging materials should be heat-sealable, cold-sealable, or ultrasonically sealable, and should be printable from the outside, without losing their protective function throughout the conversion and sealing process.

[0005] Known paper-based coated packaging materials typically contain compounds such as polyvinylidene chloride (containing halogens) or composites of paper with metal or plastic films, which have improved tear strength. This can lead to operational problems on packaging equipment and / or, due to an excessively high proportion of viscous components in the coating or the formation of so-called "sticks" on the paper fiber stream, they are generally not recyclable.

[0006] In particular, the treated fibrous materials often contain polymer components, such as those from coatings used in papermaking, which are only partially separated. For the fibrous materials treated in the waste paper loop to be reused in papermaking, it is necessary that the fibrous materials contain as few interfering components as possible. This is because once softened and bonded to paper machine components such as heated rolls, certain polymer components still attached to the fibrous materials can cause problems when reused in the papermaking process. Summary of the Invention

[0007] The object of the present invention is to provide packaging materials that exhibit improved recycling capacity in the waste paper loop, and particularly have a high recycling rate in papermaking, which is recyclable and therefore does not impair the recycling process.

[0008] In addition, the packaging material should include at least one functional coating, such as a water vapor barrier layer, an oil barrier layer, and / or a heat-sealable layer, which is preferably applied in the form of a polymer dispersion to a substrate composed of or containing fibrous materials.

[0009] This objective is achieved by a packaging material according to claim 1, comprising a substrate containing or composed of fibrous material and at least one film-forming coating, either directly or indirectly, on at least one surface of the substrate, wherein the coating is obtained by applying a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles directly or indirectly onto the substrate, followed by drying and film formation by heat input, characterized in that the polyolefin particles and / or polyolefin copolymer particles have at least one particle size distribution having a Span value (Span-Wert) of less than 1.4, preferably less than 1.0, particularly preferably less than 0.6; and the polyolefin particles and / or polyolefin copolymer particles have at least one of the following criteria:

[0010] a) D < 3.0 μm, preferably < 2.5 μm, particularly preferably < 2.0 μm 90 value;

[0011] b) D < 1.5 μm, preferably < 1.0 μm, particularly preferably < 0.8 μm 50 value;

[0012] c) D < 0.8 μm, preferably < 0.7 μm, particularly preferably < 0.65 μm. 10 value.

[0013] Preferably, these polyolefin particles and / or polyolefin copolymer particles have more than one of a) to c), and particularly preferably all of the criteria of a) to c).

[0014] Other preferred embodiments of the invention are defined in the dependent claims.

[0015] Particle size distribution was determined using laser diffraction particle size analysis according to ISO 13320 (2009). For evaluation, an optical model based on Frauhouf was used. Measurements were performed in deionized water using ultrasonic treatment. The Span value (Span-Wert) was determined to characterize the distribution width. The Span value is based on (D... 90 -D 10 ) / D 50 The wider the distribution, the larger the standard deviation and the Span value. To determine the Span value (the width of the particle size distribution), refer to Annex (S.35) of ISO 13320 (2009).

[0016] Within the scope of this invention, it has been surprisingly found that packaging materials having the features of claim 1 can be very well reused in waste paper recycling and can also be surprisingly significantly more economically prepared because the drying and film formation of coatings based on polymer dispersions containing particles, which contain particles satisfying at least one of criteria a) to d), require less heat input compared to dried polymer dispersions containing particles that do not have the features described in claim 1. The drying and film formation of the coating can be carried out at lower temperatures and / or in shorter times. Therefore, the packaging materials according to the invention are more environmentally friendly than previous packaging materials in two respects: they can be produced with less energy intensity and can be recycled very well. Furthermore, it has been surprisingly found that the packaging materials according to the invention have significantly better water vapor barrier properties compared to comparable packaging materials having coatings based on polymer dispersions containing other comparable particles but not satisfying at least one of criteria a) to d).

[0017] Within the scope of this invention, it has been found, with particular surprise, that the smallest possible Span value of the particles in the polymer dispersion after polymer particle film formation to form a coating on a substrate can result in particularly good recyclability of the coated substrate.

[0018] Unrestricted by any particular theory, it is believed that the most uniformly sized particles enable particularly uniform application, thereby rapidly forming a continuous layer on the substrate during the subsequent drying and film formation of the polymer dispersion, which can be easily removed from the substrate during recycling.

[0019] Conversely, if the Span value of polyolefin particles and / or polyolefin copolymer particles is too large, the particles not only extend primarily on the substrate surface but may also penetrate more strongly into the substrate. This makes separation of the coating from the substrate fibers difficult and thus adversely affects recycling characteristics. Furthermore, such particles penetrating into the substrate have a smaller effect on improving barrier properties compared to particles located on the substrate surface and therefore within the film-forming coating.

[0020] The packaging material according to the invention is characterized in particular by the fact that the fibrous material can be better separated from the packaging material under standard processing conditions in waste paper recycling, and thus causes fewer problems in papermaking using the separated fibrous material.

[0021] Furthermore, this packaging material, when it possesses the appropriate functionality, can be heat-sealed, cold-sealed, or ultrasonically sealed, and ensures sufficiently low water vapor permeability for use, for example, in packaging moisture-sensitive foods.

[0022] Finally, the packaging material according to the invention can be manufactured relatively simply using various methods and with a small coating weight, and can be recycled through waste paper recycling.

[0023] Numerous specific details are discussed below to provide a thorough understanding of the subject matter. However, it will be apparent to those skilled in the art that the subject matter can be practiced and modified without these specific details.

[0024] If the features of the various embodiments are not inconsistent, all features of one embodiment may be combined with features of another embodiment.

[0025] The terminology used in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the subject matter. As used herein, the singular forms "a," "an," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. Conversely, the plural forms also include the singular forms. It should also be understood that the term "and / or," as used herein, refers to and includes all possible combinations of one or more of the associated listed items. It should also be understood that the terms "comprising," "including," "comprises," and / or "includes," when used in this specification and claims, specify the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof.

[0026] In this specification and claims, the terms "comprising," "including," and / or "comprising" may also mean "consisting of," that is, excluding the presence or addition of one or more other features, steps, operations, elements, components, and / or groups.

[0027] Therefore, in this specification and claims, the term "comprising" may mean "exclusive".

[0028] Unless otherwise stated, the amounts expressed in "%" in formulations and / or compositions are based on "weight %", and in particular on the total weight of each formulation and / or composition.

[0029] As described above, the packaging material according to the present invention comprises: a substrate and at least one film-forming coating, either indirectly or directly on at least one surface of the substrate. The coating is formed from a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles, wherein the polyolefin particles and / or polyolefin copolymer particles have at least one particle size distribution with a Span value of less than 1.4, preferably less than 1.0, particularly preferably less than 0.6; and wherein the polyolefin particles and / or polyolefin copolymer particles have at least one of the following criteria: a) a Dx of less than 3.0 μm, preferably less than 2.5 μm, particularly preferably less than 2.0 μm. 90 Value; b) less than 1.5 μm, preferably less than 1.0 μm, particularly preferably less than 0.8 μm D 50c) D value less than 0.8 μm, preferably less than 0.7 μm, particularly preferably less than 0.65 μm. 10 value.

[0030] It has been found that coatings with the aforementioned properties, which are formed indirectly or directly onto a substrate, facilitate the separation of fibers from packaging materials recycled from waste paper under normal processing conditions.

[0031] If a film coating is formed directly on the substrate, it means that there are no other coatings or substances between the substrate and the coating.

[0032] If the coating is formed indirectly on the substrate, it means that there are other coatings and / or substances between the substrate and the coating.

[0033] Laboratory experiments have shown that while coatings can be applied directly to the substrate, especially when calendered base paper with surface strength and a low Cobb value is selected as the substrate, pre-coating with starch is preferred for better hold-out of the coating and to minimize the required coating application. Finally, economic and production technology considerations also determine which method is preferred in individual cases.

[0034] In one embodiment, the packaging material of the present invention is preferably characterized in that the maximum particle size of the polyolefin particles and / or polyolefin copolymer particles is less than 5 μm, preferably less than 4 μm, and particularly preferably 3 μm.

[0035] Furthermore, laboratory experiments have shown that the recyclability of packaging materials can be inferred from the optical properties of the film-forming coating. During the film formation process on the substrate, the gloss level can be adjusted by regulating process parameters, particularly the input heat, which in turn allows for the inference of the separability of the coating fibers from the substrate. In the context of this invention, gloss level is understood to refer to the Lehmann gloss level as determined according to EN ISO 8254-1:2009.

[0036] In one embodiment, the packaging material according to the invention is preferably characterized in that the film-forming coating has a Lehmann gloss of >10, preferably >20, particularly preferably >30 and especially >25 according to EN ISO 8254-1:2009.

[0037] It has been shown that insufficient film formation due to inadequate thermal action, such as too low a temperature and / or too short a temperature action time, results in lower gloss and less separable waste or scrap.

[0038] Conversely, if film formation is carried out under excessive heat, such as due to excessively high temperatures and / or excessively long temperature exposure times, this results in a smaller share of separable fibrous components, also referred to as yield. Material not discharged as waste (also known as reject) from the material preparation process by a material separation unit is called yield. Yield is derived from the following formula: Yield = (100% by weight - % by weight of reject).

[0039] Therefore, it is preferable that the film is thermally adjusted to meet the above-mentioned criteria, depending on the selection of a substrate comprising fibrous material or composed of fibrous material and a coating applied directly or indirectly in the form of a polymer dispersion to at least one side of the substrate.

[0040] Furthermore, the inventors derived two criteria from the relationship between the degree of coating film formation and the resulting proportion of separable waste to material, which the packaging material should meet in order to ensure good recyclability.

[0041] In one embodiment, the packaging material of the present invention is preferably characterized in that at least 75% by weight, preferably at least 80% by weight, and particularly preferably at least 90% by weight of the film-forming coating of the packaging material can be separated as waste, according to CEPI Recyclability Test Methods, Version 2 (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, Version 2, December 2022; and / or at least 75% by weight, preferably at least 80% by weight, and particularly preferably at least 90% by weight of the fibrous material of the substrate can be separated as material, according to CEPI Recyclability Test Methods, Version 2 (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, Version 2, December 2022.

[0042] In one embodiment, the packaging material of the present invention is preferably characterized in that, as determined by CEPI Recyclability Test Methods, 2nd Edition (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, no more than 50% by weight, preferably no more than 20% by weight and particularly preferably no more than 10% by weight of the film-forming coating of the packaging material is separated into dissolved colloidal components.

[0043] According to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and CEPI, 2nd Edition, December 2022, including the 4 Evergreen Schemes for Assessing the Recyclability of Fiber-Based Packaging, 1st Edition, January 2025, sheet tackiness can be determined and categorized into different levels. Level 1 corresponds to no sheet tackiness, and Level 2 corresponds to sheet tackiness, resulting in slight tackiness issues, but still acceptable in mixtures.

[0044] Within the scope of this application, it has been found that packaging materials with a higher proportion of film-forming agents and coatings used for waste separation have lower sheet tackiness.

[0045] In one embodiment, the packaging material of the present invention is preferably characterized in that, according to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, including the 4 Evergreen Scheme for Assessing the Recyclability of Fiber-Based Packaging, 1st Edition, January 2025, the sheet viscosity of the finely sieved material meets the viscosity requirements defined above, having a sheet tackiness of level 2 or better.

[0046] The recyclability of packaging materials is degraded by the presence of sticky impurities, also known as "sticky substances." These sticky contaminants originate from a variety of sources and can stem from, for example, coatings on packaging materials. In addition to flaky stickiness, large sticky substances are measured according to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard – Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, thus the large sticky substances per kilogram of sample are expressed in mm. 2 The area measurement shows that large adhesives are approximately less than 2000 μm per unit area.

[0047] In one embodiment, the packaging material of the present invention is preferably characterized in that, according to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, the packaging material contains less than 150,000 mm³. 2 Large adhesives with a diameter of less than 2000 μm per kg.

[0048] Before and after sorting, the manufactured paper can also be analyzed and evaluated using image analysis, according to CEPI, 2nd edition, December 2022. For this purpose, the ImageJ program can be used according to the method described below. The average particle size (average particle size) of impurities in the newly formed paper obtained thus depends on factors other than film formation, such as paper pretreatment. After sorting, i.e., after filtering out unwanted components, this value decreases sharply according to embodiments of the packaging material of the present invention. The average particle size is <40 pixels, preferably <30 pixels, particularly preferably <20 pixels. Furthermore, the coverage (area %) before sorting depends on various factors such as coating weight. However, this is also greatly reduced by the sorting process, to values ​​of <10%, preferably <5%, particularly preferably <1%.

[0049] Polymer dispersions applied directly or indirectly to a substrate are not limited in terms of the chemical composition of polyolefin particles and / or polyolefin copolymer particles, as long as the desired particle size distribution is met. However, some polymer dispersions have proven to be particularly useful.

[0050] Therefore, in one embodiment, the packaging material of the present invention is preferably characterized in that the polymer dispersion comprises a water-based polymer dispersion, preferably a water-based dispersion of anionic polymers, and particularly preferably a water-based dispersion of acid-modified anionic polymers, such as acid-modified polyolefin copolymers, especially carboxylic acid or sulfonic acid-modified polyolefin copolymers. Water-based polyolefins are described, for example, in document WO2021 / 225764A1.

[0051] In another embodiment, the polymer dispersion also contains other components or additives.

[0052] In one embodiment, the packaging material of the present invention is preferably characterized in that the film-forming coating comprises other coating components and additives, particularly for adjusting the rheological properties of the coating, preferably pigments, especially inorganic pigments such as talc, kaolin, mica, bentonite and other natural or synthetic layered silicates or flake-like precipitates of calcium carbonate.

[0053] This pigment is preferably included in the coating in an amount of 0 to 70% by weight, based on the total weight of the coating. To avoid excessively impairing the heat-sealing ability of the polymer dispersion, the amount should be selected as 0 to 50% by weight, more preferably 0 to 30% by weight, and very particularly preferably 0 to 10% by weight. 0% by weight is preferably the lower limit for exclusion.

[0054] Thin-film pigments are preferred because they can help improve barrier properties when aligned parallel to the coating lamination. Particle size is preferably selected such that the particles are completely encapsulated within the layer during lamination alignment. The aspect ratio (the ratio of average diameter to thickness, also known as the shape factor) should be greater than 10, preferably greater than 100, and particularly preferably greater than 1000.

[0055] Preferably, the coating comprises a polymer binder based on a polyolefin or polyolefin copolymer and talc as a pigment, wherein the proportion of talc relative to the total weight of the dried coating is preferably in the range of >0 to 50% by weight, preferably 15 to 40% by weight. Particularly preferred are polyethylene-based polyolefins (PE-based).

[0056] Other possible additives include, for example, thickeners, surfactants, crosslinking agents and / or rheology modifiers, particularly acrylate-based compounds or carboxymethyl cellulose (CMC), to rheologically modify or improve the stretchability of the polymer dispersion.

[0057] These additives are preferably included in an amount of 0 to 2% by weight, more preferably 0 to 1% by weight, based on the total weight of the coating. Preferably, the value of 0% by weight is excluded as the lower limit.

[0058] The roughness of the coating (according to Parker Printed Surface (PPS) DIN ISO 8791-4, 2008-05) is <6.0 μm, preferably <5.0 μm, and particularly preferably <2.0 μm.

[0059] The preferred coating application rate (ISO 536:2020-05) is 2 to 20 g / m². 2 Preferred concentration: 2.5 to 15 g / m 2 And particularly preferred 3 to 12 g / m 2 This amount pertains to the dried film-forming coating in the final product.

[0060] In one embodiment, the packaging material of the present invention is preferably characterized in that the polyolefin and / or polyolefin copolymer has a DSC starting point temperature of 70 to 80°C, a DSC peak temperature of 75 to 85°C, and / or a DSC ending temperature of 80 to 93°C.

[0061] The starting point temperature was determined using DSC as follows:

[0062] The onset temperature (according to DIN EN ISO 11357-1:2023-06) is the intersection of the baseline and the turning tangent at the beginning of the melting or crystallization peak in a DSC measurement. The baseline and turning tangent are determined by the temperature-dependent heat flux signal. In the case of pure and homogeneous materials, the onset temperature can be specified as the melting temperature. Unlike the peak temperature, the onset temperature is less dependent on the heating rate and sample quality. Furthermore, the onset temperature is often used for temperature calibration in DSC.

[0063] This packaging material is particularly well-suited for use as packaging for moisture-sensitive and water-containing objects, especially food, and can be used to manufacture bags using heat-sealing, cold-sealing, or ultrasonic sealing applications. For cold-sealing applications, water-based cold-sealing adhesives can be used. Furthermore, a barrier layer based on halogen-containing compounds is unnecessary.

[0064] In one embodiment, the packaging material of the present invention is preferably characterized in that the polyolefin particles and / or polyolefin copolymer particles comprise hydrophobic polyolefins and / or polyolefin copolymers, particularly polyolefins and / or polyolefin copolymers that form water vapor barriers.

[0065] In one embodiment, the packaging material of the present invention is preferably characterized in that the polyolefin particles and / or polyolefin copolymer particles comprise unfunctionalized ethylene-co-olefin copolymers, particularly ethylene-co-octene copolymers, ethylene-co-hexene copolymers, ethylene-co-butene copolymers, or styrene-butadiene copolymers, wherein the weight ratio of ethylene to olefin structural units is particularly in the range of 99.8:0.2, preferably 99.7:0.3, more preferably 99.6:0.4 to 50:50, more preferably to 60:40, particularly preferably to 65:35, and / or contains C1-C 12 Alkyl acrylate or C1-C 12 Ethylene copolymers with functionalized structural units of alkyl methacrylates.

[0066] As mentioned above, the film formation of polymer dispersions can be adjusted by selecting process parameters. In particular, the application of heat can be adjusted to achieve the desired properties, particularly regarding the gloss and recyclability of the packaging material.

[0067] Therefore, in one embodiment, the packaging material of the present invention is preferably characterized in that the polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles forms a film at a surface temperature of 75 to 100°C for a duration greater than 0.5 seconds, preferably greater than 1 second. Film formation can be determined based on gloss values, i.e., by selecting a temperature-time profile such that the film coating has a Lyman gloss greater than 10, preferably greater than 20, and particularly preferably greater than 30, according to EN ISO 8254-1:2009. Typically, longer times are taken at lower temperatures, for example, longer periods of gentle drying at lower temperatures, and shorter times of intense drying at higher temperatures. Those skilled in the art can determine the appropriate temperature-time profile for their respective coatings through simple experimentation.

[0068] Surface temperature refers to the temperature reached by the packaging material during film formation, and it can be adjusted according to the surface temperature and the duration of heat input.

[0069] Furthermore, a preferred feature of the packaging material according to the invention is that the coating comprises at least one wax.

[0070] The wax in the coating is preferably a wax as defined by the German Fat Research Company (DGF) below.

[0071] "Wax" is currently defined by its mechanical-physical properties. However, their chemical composition and origin vary greatly. A substance is defined as wax if it is kneadable at 20°C, is solid to brittle, has a coarse to fine crystalline structure, is translucent to opaque but not glassy, ​​melts above 40°C without decomposing, is liquid above its melting point (low viscosity), has a viscosity and solubility that are highly temperature-dependent, and can be polished under slight pressure. If a substance according to DGF does not meet one of the above characteristics, then the substance according to DGF (according to DGF standard method M-I1(75)) is not a wax.

[0072] As demonstrated by our own laboratory research, the chemical composition of the waxes used is not decisive. They should only be selected such that they melt in the coating system under technically possible dry conditions in each case. It has been found that it is advantageous to form a water vapor barrier if the melting temperature is below the boiling point of water (100°C), more preferably below 90°C.

[0073] As mentioned above, the chemical composition of the polymer dispersion is not limited in principle, but rather includes all polyolefin particles and / or polyolefin copolymer particles that meet the desired particle size distribution. However, if the polymer dispersion also contains waxes, it should also be ensured that they are compatible with each other.

[0074] In principle, hydrophobic polymers can be used. However, polar polyolefin copolymer particles can also be synthetic, naturally derived, or derivatives thereof, as long as the hydrophilic functional groups are shielded by waxes that may be present in the coating and do not impair the water vapor barrier coating.

[0075] Laboratory tests established the following relationship: lower wax content results in better heat-sealing properties, especially better hot tack. However, low wax content leads to higher water vapor permeability and a relatively high sensitivity of the water vapor barrier to grease contact. If a small amount of wax is required, the aqueous coating should be dried to allow the wax to migrate to the surface in order to achieve a good, grease-insensitive water vapor barrier.

[0076] In one implementation, the wax is a wax according to DGF (DGF Standard Method M-I1 (75)), as defined above.

[0077] In one embodiment, the packaging material of the present invention is preferably characterized in that the coating comprises a wax, wherein the wax is selected from waxes based on mixtures or pure substances of the following: short- to medium-chain hydrocarbons of fossils, animals or plants, their acids, esters, amides and / or diamines; waxes prepared by hydrogenation or partial hydrogenation of vegetable oils, vegetable fats, animal oils and / or animal fats; metal soaps, preferably based on dodecane, docosane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, triadecane, tridecane, dodecane, triterpenes, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, and nonadecane; lignite wax, carnauba wax, beeswax, candlewood wax, rice bran wax, sugarcane wax, paraffin wax, especially having an average molecular weight of at least 500 Daltons and a viscosity of at least 11 cSt at 100°C; wax obtained from sunflower cake pressing, wherein the wax is particularly preferably selected from those having a C 15 -C 17 -C(O)-OC 16 -C 18 Waxes of esters of structural unit (structural unit I); beeswax; and / or waxes obtained from at least partially hydrogenated vegetable oils, particularly soybean oil.

[0078] In another preferred embodiment, the wax of the coating consists of or contains a wax according to WO2024 / 121241A1, particularly a wax consisting of or containing one or more esters, particularly linear monoesters selected from formula (1), linear diesters of formula (2), or linear diesters of formula (3), or mixtures thereof. In the following description, such a wax is also referred to as a wax having structural unit II.

[0079] Equation (1): R1-C(O)-O-R2, where R1 is a straight-chain C3-C23 Alkyl groups, preferably straight-chain C 11 -C 17 Alkyl group, and R2 is a straight-chain C4-C group. 24 Alkyl groups, preferably straight-chain C 12 -C 18 alkyl.

[0080] Equation (2): R3-C(O)-O-R4-OC(O)-R5, where R3 and R5 are independently C3-C 23 Straight-chain alkyl groups, preferably straight-chain C 11 -C 17 -alkyl, R4 is C4-C 24 Alkyl diester, preferably straight-chain C 12 -C 18 Alkyl diol.

[0081] Equation (3): R6-OC(O)-R7-C(O)-O-R8, where R6 and R8 are independently C4-C 24 Straight-chain alkyl groups, preferably C14-24-3 ... 12 -C 18 Straight-chain alkyl, and R7 is C2-C. 22 Straight-chain alkyl diesters, preferably straight-chain C 10 To C 16 Straight-chain alkyl dimethyl groups.

[0082] In a preferred embodiment, the coating wax comprises a component having C 15 -C 17 -C(O)-OC 16 -C 18 Waxes of esters having structural unit (structural unit I), waxes having structural unit II, waxes obtained by at least partial hydrogenation of soybean oil, and / or paraffin wax.

[0083] Beeswax and / or paraffin are particularly preferred, as confirmed in accordance with BfR, XXVI, 01.04.2021, Chapter C, Section IV, point 2, see BfR, XXV, 01.06.2019, issued by the Federal Institute for Risk Assessment of the Federal Ministry of Food and Agriculture, Germany.

[0084] When using paraffin-based materials, those classified according to "FCM Substance No. 94 in European Commission Regulation No. 10 / 2100 of January 14, 2011, 'on plastic materials and articles intended to come into contact with food'" are particularly preferred.

[0085] Furthermore, it is preferred to use an aqueous wax dispersion obtained by dispersing (A) a nonionic surfactant, (B) anionic surfactant and (C) wax in water, characterized in that the wax (C) comprises an ester compound having fatty acid-derived structural units and fatty alcohol-derived structural units, wherein the content of the nonionic surfactant (A) is 40-99 parts by weight relative to 100 parts by weight of the total amount of the nonionic surfactant (A), anionic surfactant (B) and wax (C), and 5-50 parts by weight relative to 100 parts by weight of the total amount of the nonionic surfactant (A), anionic surfactant (B), wax (C) and water.

[0086] In one embodiment, the polymer dispersion comprises only polyolefin particles and / or polyolefin copolymer particles and wax, wherein a certain weight ratio of polyolefin particles and / or polyolefin copolymer particles to wax is advantageous.

[0087] In a preferred embodiment, the coating comprises a film-forming polyolefin obtained by forming a film, particularly a polyolefin as defined above, and comprises a C 15 -C 17 -C(O)-OC 16 -C 18 Waxes of esters having structural unit (structural unit I), waxes having structural unit II, waxes obtained by at least partial hydrogenation of soybean oil, and / or paraffin wax.

[0088] In one embodiment, the packaging material of the present invention is preferably characterized in that the weight ratio of polyolefin and / or polyolefin copolymer to wax in the (film-forming) coating is 70:30 to 99.5:0.5, preferably 80:20 to 99:1, particularly preferably 85:15 to 98:2, especially 90:10.

[0089] In a preferred embodiment, the layer comprising starch (starch layer) and / or its modifier (modified starch) may be present directly on at least one side of the substrate, preferably directly on both sides of the substrate of the packaging material according to the invention.

[0090] Preferably, the concentration is 0.1 to 3, particularly preferably 0.2 to 1.5 g / m³. 2Apply a starch coating in appropriate amounts.

[0091] The advantages of a starch coating on the side of the substrate where the coating is applied are that the substrate is sealed, thus improving the adhesion of the coating and reducing or preventing the coating from penetrating into the substrate.

[0092] The starch coating preferably has a Bekk smoothness of more than 20 seconds, particularly more than 50 seconds, and very particularly more than 50 to 200 seconds.

[0093] In addition, for example, the uncoated side of the substrate may be provided with one or more other coatings, which are easier to print on than the surface of the base paper that only has a starch coating.

[0094] In one embodiment, the packaging material according to the invention is preferably characterized by applying a pre-coating directly on at least one side of the substrate, preferably directly on both sides of the substrate.

[0095] Preferably, the starch coating as defined above and, in particular, a pre-coating as defined below, exist in this order between the substrate and the coating.

[0096] Preferably, this pre-coating (also known as a primer) contains at least one inorganic pigment and a polymer binder or is composed of them.

[0097] Inorganic pigments are preferably in the form of flakes, and particularly include talc, precipitated calcium carbonate or silicates, preferably layered silicates, and very particularly preferably kaolin.

[0098] The aspect ratio (the ratio of average diameter to thickness, also known as the shape factor) of the flake pigment should be about 7 to 40 to 1, preferably about 15 to 30 to 1.

[0099] The particle size of the flake pigment is preferably adjusted such that at least about 70%, preferably at least about 85%, of the particles have a particle size of about <2 μm (Sedigraph). The pH of the flake pigment in aqueous solution is preferably 6 to 8.

[0100] Suitable polymeric adhesives, especially those based on acrylates or styrene / butadiene, should be mentioned. In principle, all polymers that can be used as pigment binders in the paper industry are suitable. Carbohydrate-based adhesives, particularly starch-based adhesives (solutions of modified starch, dispersions of cross-linked starch, so-called bio-latex) and polymer-starch-hybrid latexes, as well as protein-based adhesives such as casein, can also be used.

[0101] Polymer adhesives preferably include polyacrylate-based polymer adhesives.

[0102] The polymeric adhesive preferably includes a styrene-acrylate copolymer, more preferably a styrene-butyl acrylate copolymer, and especially a styrene-n-butyl acrylate copolymer.

[0103] Suitable styrene-butyl acrylate copolymers are known, for example, under the trade name Acronal S 305 FD.

[0104] The pre-coating can be generally hydrophobic.

[0105] In another implementation, the top coating is generally hydrophilic.

[0106] The coatings described above preferably contain 5 to 50% by weight, more preferably 10 to 30% by weight, of a polymer binder. The amount refers to the dried pre-coating in the final product.

[0107] Furthermore, the pre-coating preferably contains 50 to 95% by weight, more preferably 65 to 85% by weight, of inorganic pigments. The amount refers to the dried pre-coating layer in the final product.

[0108] In addition, the pre-coating may contain additives such as thickeners, for example acrylate-based thickeners, surfactants, and / or rheology modifiers. Crosslinking agents may also be used. Preferably, the pre-coating contains an ammonium carbonate-zirconium carbonate crosslinking agent and is itself crosslinked with formaldehyde.

[0109] These additives are preferably present in an amount of 0 to 2% by weight, more preferably greater than 0 to 2% by weight, wherein a value of 0% by weight is preferably excluded. The amount refers to the dried pre-coating in the final product.

[0110] The coating amount (ISO436:2020-05) for the pre-coating is preferably 1 to 20 g / m². 2 Especially preferred is 2 to 12 g / m 2 The quantity refers to the dried pre-coating in the final product.

[0111] The advantage of applying this pre-coating is that it seals the substrate surface, causing only slight migration of any other coating applied to it into the paper. Furthermore, the pre-coating reduces the average roughness of the substrate and provides advantageous holdout, characterized by uniform application and defined surface energy, allowing the coated polymer dispersion to form an optimal coating film and to create an optimal barrier with minimal application, which has a favorable impact on cost structure. Additionally, the pre-coating is formulated such that the adhesion of the intermediate layer between the substrate and the coating is not significantly reduced, which can be important for subsequent sealing applications. This is also applicable if a starch layer exists between the pre-coating and the substrate.

[0112] The surface tension (or surface energy) of the pre-coated material is preferably 15 to 40 mN / m, particularly 22 to 30 mN / m.

[0113] Surface tension was determined according to DIN EN ISO 19403-2:2020-04:

[0114] For good wetting and adhesion of the intermediate layer, the surface tension of the pre-coated layer should be higher than or at least more polar than the surface tension of the layer above it.

[0115] When necessary, it is important to ensure that the surface tensions of the coating and the pre-coating are coordinated. High-polarity primers can over-swell when applied with water-based coating formulations, leading to cracking after drying. Therefore, the aforementioned data on the surface tension of the pre-coating has proven to be particularly effective.

[0116] The smoothness of the pre-coating (according to Bekk (ISO5627-1995-03)) is preferably 80 to 200 s, more preferably 90 to 120 s.

[0117] The roughness of the pre-coating (according to Parker-Print-Surf (PPS) DIN ISO 8791-4, 2008-05) is preferably 2.8 to 4.0 μm, more preferably 3.2 to 3.6 μm.

[0118] In one embodiment, in addition to the pre-coating and coating described above, the packaging material according to the invention may also include other layers, such as sealing coatings, like cold-sealing adhesives or additional heat-sealing adhesives, metallizations and / or other barrier layers (water vapor barrier layer, oxygen barrier layer, mineral oil barrier layer, oil and fat barrier layer, aromatic barrier layer). These layers may be applied indirectly or directly to at least one side of the substrate, or between the various layers of the packaging material.

[0119] In one embodiment, the packaging material of the present invention is preferably characterized in that the packaging material includes at least one other coating.

[0120] To improve the overall barrier properties of packaging materials, smooth surfaces can be made by metallizing them with metal or metal oxides (e.g., by vacuum vapor deposition).

[0121] This preferably requires a smooth surface or a smooth printed layer on the uncoated side of the substrate.

[0122] Barrier coatings are also known, which can be applied, for example, to the entire surface or only to specific areas.

[0123] One example is manufacturer Hubergroup Print Solutions' HYDRO-LAC GA oxygen barrier coating. This coating can be applied to a coated layer or to an uncoated surface of a substrate, or preferably to a smooth printing surface.

[0124] Packaging materials can be heat-sealed; however, there is also the possibility of applying a cold-sealing adhesive to one of the two sides of the packaging material, especially when the packaging material is to be used on packaging equipment designed for cold-sealing.

[0125] Preferably, one of the two sides, preferably the pressure side, can also be equipped with another heat-sealing adhesive for heat sealing between the front and rear sides (A / B-heat sealing).

[0126] Such packaging materials are in particular heat-sealable, cold-sealable, or ultrasonically sealable, or may be knurled (e.g., by means of knurling in a packaging machine, including packaging of the packaging material according to the invention) and ensure sufficient sealability so that they can also be used, for example, for packaging of moisture-sensitive and oily foods.

[0127] In one embodiment, the encapsulation material includes a pre-coating and a coating as defined above.

[0128] The aforementioned pre-coating layer can be applied in one, two, or more layers.

[0129] In a preferred embodiment, the packaging material includes a starch-coated substrate, a pre-coating, and a coating as defined above.

[0130] The substrates used in the packaging materials according to the present invention are, in principle, not limited.

[0131] In one embodiment, the packaging material according to the invention is preferably characterized in that the substrate comprises paper, cardboard, or paperboard, preferably having a basis weight (basic weight) of 20 to 120 g / m². 2 Preferred concentration: 50 to 100 g / m 2 The paper.

[0132] Furthermore, preferably, the substrate comprises long fibers and short fibers, wherein the long fibers are fibers having a fiber length of 2.6 to 4.4 mm, the short fibers are fibers having a fiber length of 0.7 to 2.2 mm, and the content of long fibers is preferably 10 to 80% by weight, preferably 20 to 60% by weight, and the content of short fibers is preferably 20 to 90% by weight, preferably 50 to 70% by weight.

[0133] The long fiber content particularly ensures the strength of relatively thin paper, while the short fiber content particularly makes the paper denser and more closed, giving it a uniform appearance. Increasing the long fiber content further would make the paper too stiff. Another factor is that short fiber pulp is less expensive than long fiber pulp.

[0134] In addition, the substrate may contain 0% to 20% by weight, preferably 0% to 5% by weight, of fillers, wherein the value of 0% by weight is preferably excluded, such as GCC (heavy calcium carbonate) known, for example, under the trade names Hydrocarb 60 or Hydroxplex 60, PCC (precipitated calcium carbonate) known, for example, under the trade name Precarb105, natural kaolin and / or talc.

[0135] In addition, conventional additives, such as retention aids and / or sizing agents, can be included in the substrate.

[0136] Specifically, for food contact, the substrate comprises at least 60% by weight, preferably at least 75% by weight, of fibrous material, up to 25% by weight, preferably up to 10% by weight, of filler, and up to 15% by weight, of additives. Furthermore, trace amounts of processing aids (e.g., reagents, dispersants, anti-caking agents, etc.) may be present in the substrate, whether unavoidable or even necessary.

[0137] The advantages of this substrate lie in its high flexibility and its good processability on existing packaging equipment for flexible materials such as plastic films, maintaining high machine availability and achieving the required puncture resistance.

[0138] The packaging material of the present invention can be economically obtained using all known papermaking and coating methods (with or without pre-conditioning, film press, roll coating, blade coating, curtain coating, spray coating).

[0139] However, the packaging material of the present invention is preferably obtained by means of a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles being applied directly or indirectly to at least one side of a substrate, wherein the applied suspension has a solid content of 20 to 60% by weight, preferably 30 to 50% by weight, and is applied by a curtain coating method at an operating speed of at least 300 m / min of a coating equipment, and then a film is formed by heat input to obtain a coating, which is preferably carried out by means of IR drying and / or hot air drying.

[0140] In one embodiment of the method of the present invention, the polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles forms a film at a surface temperature of 75-100°C, preferably for a time period of more than 0.5 seconds, and more preferably more than 1 second.

[0141] For drying the coated suspension, non-contact methods have proven suitable, such as IR-drying and / or hot air drying, where the heat input can be individually adjusted. This method is particularly advantageous from an economic standpoint, and because of the uniform coating on the substrate, preferably the paper web.

[0142] If the solids content is below approximately 20% by weight, the economics deteriorate because a large amount of water must be removed quickly through gentle drying, which negatively impacts the coating speed. On the other hand, if the value exceeds 60% by weight, this only leads to increased technical complexity in ensuring the stability of the coating suspension during the coating process and the drying of the applied film, as the machine must again operate at a very high speed in this case.

[0143] In the curtain coating method (curtain coating method), a curtain is formed by the free fall of a coating suspension. By free fall, the coating suspension, which exists in the form of a thin film (curtain), is "cast" onto a substrate in order to coat the coating suspension onto the substrate. DE10196052T1 discloses the use of this curtain coating method in the production of information recording materials, wherein a multilayer recording layer is achieved by coating a curtain composed of multiple coating dispersion films onto a substrate.

[0144] In a preferred embodiment of the method of the present invention, the viscosity of the degassed aqueous coating suspension is about 100 to about 400 mPas (Brookfield, 100 rpm, 20°C). Values ​​below about 80 mPas or above about 500 mPas result in poor flowability of the coating composition on the coating unit. More preferably, the viscosity of the degassed aqueous coating suspension is about 150 mPas to about 300 mPas.

[0145] In a preferred embodiment, to optimize the method, the dynamic surface tension of the polymer aqueous dispersion can be adjusted to approximately 35 to approximately 55 mN / m, preferably approximately 38 to approximately 52 mN / m (measured 50 ms after foaming), according to the bubble pressure measurement standard (ASTM D 3825-90) described below. Better control of the coating method is achieved by determining the dynamic surface tension of the polymer dispersion and specifically adjusting this dynamic surface tension by selecting a suitable surfactant and by determining the desired amount of surfactant.

[0146] For development purposes and for prototype production, the paper can also be produced on a laboratory scale using a hand-held doctor blade and then dried in a drying oven. Drying can be performed, for example, similar to the heat treatment described above, in a drying oven at 90°C for 3 minutes. Since the risk of boiling bubbles forming during this slow drying process is low, the temperature can also be set above 100°C, preferably 105°C.

[0147] In other embodiments, the polymer dispersion can also be applied to the substrate by the following methods:

[0148] Polymer dispersions can be applied to substrates using printing methods such as flexographic and gravure printing.

[0149] The present invention also relates to packaging materials, which can be obtained by the above method.

[0150] In an alternative embodiment, the packaging material according to the invention is manufactured, in particular, by a method comprising the following steps:

[0151] -Provide substrates, especially paper substrates;

[0152] - A polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles is applied directly or indirectly to at least one surface of the substrate, wherein the particles have at least one of the following criteria:

[0153] -Provide substrates, especially paper substrates;

[0154] - Applying a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles directly or indirectly to at least one surface of the substrate, characterized in that the polyolefin particles and / or polyolefin copolymer particles have at least one particle size distribution having a Span value of less than 1.4, preferably less than 1.0, particularly preferably less than 0.6; and the polyolefin particles and / or polyolefin copolymer particles have at least one of the following criteria: a) a Di of less than 3.0 μm, preferably less than 2.5 μm, particularly preferably less than 2.0 μm. 90 Value; b) less than 1.5 μm, preferably less than 1.0 μm, particularly preferably less than 0.8 μm D 50 c) D value less than 0.8 μm, preferably less than 0.7 μm, particularly preferably less than 0.65 μm. 10 Value; d) The difference between the starting temperature and the ending temperature of the particles measured by DSC shall not exceed 20°C, preferably not exceed 15°C;

[0155] The polymer dispersion is dried and film-formed by heat input to provide the coating.

[0156] In a preferred embodiment of this alternative method, the drying and film formation of the polymer dispersion are carried out by heat introduction in such a way that the surface temperature of the coating is no more than 30°C higher than the DSC melting point of the particles for no more than 60 seconds, preferably no more than 20°C, particularly preferably no more than 30 seconds, very particularly preferably no more than 10 seconds, and especially no more than 1 second, of which 0 seconds is completely preferred.

[0157] The DSC melting point was determined according to DIN EN ISO11357-1:2023-06 (DSC peak value).

[0158] In other embodiments of the above method, the polymer dispersion comprises a water-based polymer dispersion.

[0159] The present invention also relates to packaging materials that can be obtained by the above-described alternative methods or alternative embodiments thereof.

[0160] Finally, the present invention also relates to the use of the packaging materials described above as packaging materials or as components of packaging materials, particularly heat-sealable, cold-sealable or ultrasonically sealable packaging, preferably for food, cosmetics, hygiene products, tobacco, especially for packaging moisture-sensitive foods and / or fatty foods, and for protecting them from ambient humidity or fat.

[0161] The packaging material according to the invention can be used in all conventional packaging equipment. Examples include vertical and horizontal tubular bag machines (forming-filling-sealing) for manufacturing, in particular, stand-up pouches, flow packs, or pillow packs; air bags or pads as alternatives to plastic air cushion bags or pads; machines that bring together two webs of the same or different materials and join them by heat sealing, such as pallet machines, conveyor belt machines (also with vacuum), bag filling and sealing machines, thermoforming packaging machines, linear filling machines for applying container caps for packaging by heat sealing; and sealing machines, blister packaging machines, and X-Fold packaging machines with a final heat sealing step.

[0162] The present invention will now be described in detail with reference to non-limiting embodiments. Detailed Implementation

[0163] Example

[0164] For Examples 1 to 10 and Comparative Examples 1 to 3, paper from the production line was used as the substrate.

[0165] On the relevant papermaking machine, pure base paper (40% by weight long fiber, 60% by weight short fiber) was produced, polished with polishing tools, and enzymatically degraded cationic modified potato starch (approximately 1 g / m³) was added using a membrane press. 2 The coating is applied to both sides. According to ISO 536, the basis weight of the base paper is 60 g / m². 2 (2020).

[0166] The paper machine is equipped with a calendering cylinder (Yankee cylinder), which enables it to produce paper with a smooth surface on one side.

[0167] In the second step, the respective amounts of the polymer dispersion are applied to each piece of paper. The components are shown in Table 1.

[0168] The drying unit consists of a series of infrared electric dryers, followed by a series of air hoods (hot air dryers).

[0169] After the polymer dispersion is coated onto these paper substrates in a coating machine, the coated paper substrates are dried, wherein the following drying parameters are adjusted: the maximum air temperature in the drying unit is 160°C (controlled by measuring the maximum surface temperature of the coated paper substrate); the maximum surface temperature of the coated paper substrate is 80°C; and the drying time is 1.46 seconds.

[0170] The coated paper is then post-dried and formed into a film in a drying oven (hot air furnace) according to the instructions in Table 1. Post-drying is preferably carried out in a hot air furnace to ensure that the paper is actually exposed to the appropriate temperature for the appropriate time period. For this purpose, the furnace must be preheated and have a sufficient internal volume (>100 dm²). 3 The dimensions (e.g., width x height x depth 60cm x 48cm x 37cm) are used to allow the front door to be opened briefly (2-3 seconds) so that no significant temperature drop occurs when the paper is placed inside. The paper is placed on a metal grid located at the middle height of the furnace, preferably with cardboard laid flat on the grid as a base. The metal grid and cardboard must have been preheated to the furnace temperature and placed in the furnace, which has been preheated to the required temperature, for at least 15 minutes before the heat treatment begins. The hot air furnace is located in a climate-controlled space with 23°C and 50% relative humidity, so the paper is at 23°C before being placed inside the furnace.

[0171] To determine recyclability and gloss, the hot air furnace temperature and residence time were varied. The corresponding temperatures and times used for post-film formation are given in Table 1.

[0172] The main components, drying parameters, and determined properties of the packaging materials for each coating are summarized in Table 1 below.

[0173] Lyman gloss was determined photometrically using a converging beam at 75° according to EN ISO 8254-1:2009. Measurements were taken of the coatings under various coating conditions, varying surface temperature and residence time. The process parameters are listed in Table 1.

[0174] The particle size distribution of polyolefin particles and / or polyolefin copolymer particles is determined by laser diffraction particle size analysis. The calculation of the average particle size distribution is described in ISO 9276-2 (2018). To characterize the distribution width, the Span value (span) is determined. According to (D... 90 -D 10 ) / D 50 Calculate the Span value.

[0175] To evaluate recycling performance, the material composition and waste were determined. For this purpose, manufactured packaging materials were tested according to CEPI Laboratory Methods for Recyclability, 2nd Edition (October 2022) and according to Laboratory Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, including 4 Evergreen Schemes for Assessing the Recyclability of Fiber-Based Packaging, 1st Edition, January 2025.

[0176] To perform image analysis using ImageJ (Freeware-Software), a laboratory sheet was scanned at a resolution of 600 dpi and converted into a black and white image (8-bit representation, see appendix). Figure 1 -4 (example). The image is then cropped to a size of 3000x3500 pixels around the center (see examples in Figures 5-8) and converted into a binary image (see examples in Figures 9-12). The waste / particles are imaged in white, while the surrounding lab sheet is imaged in black. This allows for particle detection, i.e., image-based identification of the waste / particles and pixel counting of them (see examples in Figures 13-16). Here, in the particle analysis procedure, settings considering each shape and size of particle are used (size: 0-infinity and 0.00-1.00 for circles).

[0177] The program specifically provides two parameters: area %, which represents the percentage of waste / particle area in the image, and average size, which represents the average particle size in pixels.

[0178] The results of the analysis are summarized in Figure 1 middle.

[0179] Table 1: Examples

[0180]

[0181]

[0182]

[0183]

[0184] 1) Film formation without coating

[0185] 2) Theoretical coating ratio: [Coating weight of polymer dispersion containing coating additives / (Base paper weight + Coating weight of polymer dispersion containing coating additives)]

[0186] 3) Theoretical coating removal rate: [Waste / Theoretical coating ratio]

[0187]

[0188]

[0189]

[0190]

[0191]

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198]

Claims

1. Packaging materials, including: A substrate comprising or composed of fibrous material, and at least one film-forming coating indirectly or directly on at least one surface of the substrate, wherein the coating is obtained by applying a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles indirectly or directly onto the substrate, and drying and forming a film by heat input, characterized in that the polyolefin particles and / or polyolefin copolymer particles have at least one particle size distribution: a Span value of <1.4, preferably <1.0, particularly preferably <0.6; and the polyolefin particles and / or polyolefin copolymer particles have at least one of the following criteria: a) a Di of less than 3.0 μm, preferably less than 2.5 μm, particularly preferably less than 2.0 μm. 90 Value; b) less than 1.5 μm, preferably less than 1.0 μm, particularly preferably less than 0.8 μm D 50 c) D value less than 0.8 μm, preferably less than 0.7 μm, particularly preferably less than 0.65 μm. 10 value.

2. The packaging material according to claim 1, characterized in that, The maximum particle size of the polyolefin particles and / or polyolefin copolymer particles is less than 5 μm, preferably less than 4 μm, and particularly preferably 3 μm.

3. The packaging material according to claim 1 or 2, characterized in that, The film-forming coating has a Lyoman gloss of greater than 10, preferably greater than 20, and particularly preferably greater than 25, according to EN ISO 8254-1:2009.

4. The packaging material according to any one of the preceding claims, characterized in that, According to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and / or according to the Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, at least 75% by weight, preferably at least 90% by weight, of the film-forming coating of the packaging material may be separated as waste, and / or according to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and / or according to the Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, at least 75% by weight, particularly preferably at least 90% by weight, of the fibrous material of the substrate may be separated as material.

5. The packaging material according to any one of the preceding claims, characterized in that, According to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and / or according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, including the 4 Evergreen Scheme for Assessing the Recyclability of Fiber-Based Packaging, 1st Edition, January 2025, the packaging material has a sheet tackiness of Level 2 or better.

6. The packaging material according to any one of the preceding claims, characterized in that, According to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and / or according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, the packaging material contains less than 150,000 mm² 2 / kg, preferably less than 50,000 mm 2 Large adhesives with a diameter of less than 2000 μm per kg.

7. The packaging material according to any one of the preceding claims, characterized in that, According to CEPI Recyclability Test Methods, 2nd Edition (October 2022) and / or according to Laboratory Test Methods for Recyclability of Paper and Paperboard - Part I: Recycling Plants Using Conventional Methods, CEPI, 2nd Edition, December 2022, no more than 50% by weight, preferably no more than 20% by weight and particularly preferably no more than 10% by weight of the film-forming coating of the packaging material is separated into dissolved colloidal components.

8. The packaging material according to any one of the preceding claims, characterized in that, The polymer dispersions include water-based polymer dispersions, preferably water-based dispersions of anionic polymers, and particularly preferably water-based dispersions of anionic acid-modified polymers.

9. The packaging material according to any one of the preceding claims, characterized in that, The film-forming coating comprises other coating components and additives, particularly those used to adjust the rheological properties of the coating, preferably pigments, especially inorganic pigments, layered silicates, talc, kaolin, or flaky precipitated calcium carbonate.

10. The packaging material according to any one of the preceding claims, characterized in that, The polyolefin particles and / or polyolefin copolymer particles have a DSC starting point temperature of 70 to 80°C, a DSC peak of 75 to 85°C, and / or a DSC ending temperature of 80 to 93°C.

11. The packaging material according to any one of the preceding claims, characterized in that, The polyolefin particles and / or polyolefin copolymer particles comprise hydrophobic polyolefins and / or polyolefin copolymers, particularly polyolefins and / or polyolefin copolymers that form water vapor barriers.

12. The packaging material according to any one of the preceding claims, characterized in that, The polyolefin particles and / or polyolefin copolymer particles comprise unfunctionalized ethylene-co-olefin copolymers, particularly ethylene-co-octene copolymers, ethylene-co-hexene copolymers, and ethylene-co-butene copolymers, wherein, in particular, the weight ratio of ethylene to olefin structural units is in the range of 99.8:0.2, preferably 99.7:0.3, more preferably 99.6:0.4 to 50:50, even more preferably 60:40, and particularly preferably 65:35, and / or contains C1-C 12 Alkyl acrylate or C1-C 12 Ethylene copolymers with functionalized structural units of alkyl methacrylates.

13. The packaging material according to any one of the preceding claims, characterized in that, The polymer dispersion containing polyolefin particles and / or polyolefin copolymer particles forms a film at a surface temperature of 65 to 110°C, preferably 75 to 100°C, for a time greater than 0.5 seconds, and more preferably greater than 1 second.

14. The packaging material according to any one of the preceding claims, characterized in that, The coating comprises wax, particularly wax selected from mixtures or pure substances based on: short- to medium-chain hydrocarbons of fossils, animals, or plants, their acids, esters, amides, and / or diamines; waxes prepared by hydrogenation or partial hydrogenation of vegetable oils, vegetable fats, animal oils, and / or animal fats; metal soaps, preferably based on dodecane, docosane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, triadecane, tridecane, dodecane, triterpenesane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, and nonadecane; lignite wax, carnauba wax, beeswax, candle wax, rice bran wax, sugarcane wax, paraffin wax, particularly having an average molecular weight of at least 500 Daltons and a viscosity of at least 11 cSt at 100°C; wax obtained from sunflower cake pressing, wherein the wax is particularly preferably selected from substances having a C 15 -C 17 -C(O)-OC 16 -C 18 Ester waxes containing structural unit I and waxes containing structural unit II; beeswax; and / or Waxes obtained from at least partially hydrogenated vegetable oils, particularly soybean oil.

15. The packaging material according to claim 13, characterized in that, The weight ratio of polyolefin and / or polyolefin copolymer to wax in the coating is 70:30 to 99.5:0.5, preferably 80:20 to 99:1, and particularly preferably 85:15 to 98:

2.

16. The packaging material according to any one of the preceding claims, characterized in that, The packaging material includes at least one additional coating.

17. The packaging material according to any one of the preceding claims, characterized in that, A pre-coating is applied directly to at least one side of the substrate, preferably directly to both sides of the substrate.

18. The packaging material as claimed in any one of the preceding claims, characterized in that, The substrate includes paper, cardboard, or paperboard, preferably with a basis weight of 20 to 120 g / m³. 2 Preferred concentration: 25 to 100 g / m 2 The paper.

19. A method for manufacturing packaging material according to any one of claims 1 to 18, characterized in that, A polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles is applied directly or indirectly to at least one surface of the substrate, wherein the applied suspension has a solids content of 20 to 60% by weight, preferably 30 to 50% by weight, and is applied by a curtain coating method at an operating speed of at least 300 m / min of the coating equipment, and subsequently formed by heat input to obtain a coating, wherein the film formation is preferably carried out by means of IR drying and / or hot air drying.

20. Packaging material, which can be obtained by the method of claim 19.

21. A method for manufacturing packaging materials, particularly packaging materials according to any one of claims 1 to 18, comprising the following steps: -Provide substrates, especially paper substrates; - Applying a polymer dispersion comprising polyolefin particles and / or polyolefin copolymer particles directly or indirectly to at least one surface of the substrate, characterized in that the polyolefin particles and / or polyolefin copolymer particles have at least one particle size distribution having a Span value of less than 1.4, preferably less than 1.0, particularly preferably less than 0.6; and the polyolefin particles and / or polyolefin copolymer particles have at least one of the following criteria: a) a Di of less than 3.0 μm, preferably less than 2.5 μm, particularly preferably less than 2.0 μm. 90 Value; b) less than 1.5 μm, preferably less than 1.0 μm, particularly preferably less than 0.8 μm D 50 c) D value less than 0.8 μm, preferably less than 0.7 μm, particularly preferably less than 0.65 μm. 10 Value; d) The difference between the starting temperature and the ending temperature of the particles measured by DSC shall not exceed 20°C, preferably not exceed 15°C; - The polymer dispersion is dried and film-formed by heat input to obtain the coating.

22. The method of claim 21, wherein the drying and film formation of the polymer dispersion are carried out by heat input such that the surface temperature of the coating is not more than 30°C above the DSC melting point of the particles, preferably not more than 20°C, for a duration not exceeding 60 seconds, particularly preferably not more than 30 seconds, very particularly preferably not more than 10 seconds, especially not more than 1 second, wherein 0 seconds is very particularly preferred.

23. The method of claim 21 or 22, wherein the polymer dispersion comprises a water-based polymer dispersion.

24. Use of the packaging material according to any one of claims 1 to 18 or claim 20 as packaging or as part of packaging, wherein the packaging is in particular heat-sealable, cold-sealable or ultrasonically sealable packaging, preferably for food, cosmetics, hygiene products, tobacco, especially for packaging moisture-sensitive foods and / or fatty foods, and for protecting them from ambient humidity or grease.

Images