Cellulose-based three-dimensional shaped substrates comprising cellulosic fibers and non-fibrous cellulosic materials, methods for preparing same, and uses thereof

Abstract

The present invention relates to a three-dimensionally shaped cellulose-based substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, a method for preparing a three-dimensionally shaped cellulose-based substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, a method for processing a three-dimensionally shaped cellulose-based substrate, and the use of a three-dimensionally shaped cellulose-based substrate for packaging.

Description

[Technical Field]

[0001] The present invention relates to a cellulose-based three-dimensionally shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the three-dimensionally shaped substrate comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; and (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated. The present invention also relates to the above-mentioned method for preparing a three-dimensional shaped cellulose-based substrate, a method for processing a three-dimensional shaped cellulose-based substrate, and uses thereof. [Background technology]

[0002] Cellulose-based food packaging materials are preferred for use in the industry because they are inexpensive to produce, generally safe for food contact, and have a relatively low environmental impact.

[0003] Such food packaging materials often must be molded or otherwise formed into a three-dimensional shape to hold food therein. However, traditional three-dimensional paper materials may be unsuitable for food packaging applications because the hydrophilic cellulose fibers in the material and its porous structure make them highly permeable to water, gas, and oil. Therefore, these materials may not provide an adequate barrier that leads to leakage. Until now, this problem has been overcome by adding an extra barrier to the surface of the packaging material, for example, by dispersion coating, film lamination, or extrusion coating. However, such methods incur additional processing steps and materials that simultaneously increase costs and environmental impact.

[0004] Parchment paper offers several advantages as a packaging material, such as providing oil and water resistance, providing a gas barrier, and being biodegradable and / or compostable. Therefore, such products combine high barrier properties with low cost and environmental impact, as no additional coating step with a polymer film is required. Furthermore, parchment-based products are generally considered safe for food contact and have long been used by consumers to package and / or prepare food. Parchment-based products can also be processed in multiple ways, such as by printing product labels.

[0005] However, parchment paper is characterized by low flexibility due to the densification of the material during the parchmentation process. Therefore, three-dimensional forming steps, for example by thermoforming, are difficult to perform on parchment paper because the low flexibility of the material regularly causes tears, especially in areas of concentrated stress, such as areas of high curvature and sharp edges. This can cause mechanical failure of the material in the affected areas and reduce its barrier properties.

[0006] WO 2021 / 001276 discloses a dry-forming process for cellulose food packaging products from a sheet-like cellulose blank structure, preceded by a coating step of an alkylketene dimer dispersion and a latex dispersion. Thus, the alkylketene dimer and latex dispersion form an additional film on the cellulose blank structure that retains its barrier properties during the dry-forming process. However, the synthetic barrier film adds additional processing and material costs.

[0007] WO2021 / 089778 discloses a compostable cellulose-based parchment-like material with high gas barrier properties. However, due to the densification required to achieve the necessary gas barrier properties, the material is relatively inflexible and may therefore have limited ability to undergo three-dimensional molding processes.

[0008] Therefore, there remains room for improvement and there is a need for a cellulose-based, three-dimensional shaped packaging product that utilizes the advantageous barrier properties of parchment, thereby reducing the need for an additional coating step with a barrier-providing film. Summary of the Invention

[0009] The present invention solves the problems of the prior art by the following means.

[0010] In a first aspect, the present invention relates to a cellulose-based three-dimensional shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the three-dimensional shaped substrate comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

[0011] In a second aspect, the present invention relates to a method for preparing a cellulose-based three-dimensionally shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the method comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

[0012] In a third aspect, the present invention relates to a method for processing a cellulose-based three-dimensionally shaped substrate according to the first aspect of the invention, wherein the processing comprises any of printing, laminating, coating, painting, spraying, bonding, gluing, varnishing, impregnating, dipping, and / or bonding.

[0013] In a fourth aspect, the present invention relates to the use of a cellulose-based three-dimensionally shaped substrate according to the first aspect of the invention for packaging, preferably for packaging food products such as single-serving drink capsules, electronics packaging, cosmetic packaging and / or medical product packaging. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 shows a schematic diagram of a method for preparing a cellulose-based three-dimensionally shaped substrate according to one embodiment of the present invention. [Figure 2] The figure is subdivided into Panels A-D. Panel A shows a photograph of a thimble and its treated product, as further developed in Example 1. On the left side of the photograph, the entire thimble is untreated. On the right side of the photograph, the half of the thimble to the right of the thimble's long axis has been treated, as further developed in Example 1. Panel B shows a higher magnification photograph of a sample treated in Example 1. The left side of the sample is untreated, with individual fibers visible. The right side is at least partially parchmented and contains non-fibrous cellulosic material. Individual fibers are not visible, and the material is densely packed. Panel C shows scanning electron micrographs of an untreated and treated sample from Example 1, respectively. In the micrograph of the untreated sample, individual fibers are visible. In the micrograph of the treated sample, individual fibers are not visible. Panel D shows further scanning electron micrographs of an untreated and treated sample from Example 1, respectively, at higher magnification. [Figure 3] 1 shows the results of the oil resistance test for Example 1. The photo on the left shows the inside of the thimble (where the dye was applied) and the photo on the right shows the outside. The long axis of the thimble is indicated by the dotted line. [Figure 4]The diagram is subdivided into Panels A-D. Panel A shows a photograph of an egg container and its treated product, as further developed in Example 2. The egg-holding cavities are labeled 1 and 2. Side 1 is treated, and side 2 is untreated. Panel B shows a higher magnification photograph of a sample treated in Example 2. The left side of the sample is untreated, with individual fibers visible. The right side is at least partially parchmented and contains non-fibrous cellulosic material. A continuous cellulosic fiber matrix can be observed in the lower right. Panel C shows scanning electron micrographs of an untreated and treated sample from Example 2, respectively. In the micrograph of the untreated sample, individual fibers are visible. In the micrograph of the treated sample, individual fibers are visible, but the surface is smooth and dense. Panel D shows additional scanning electron micrographs of an untreated and treated sample from Example 2, respectively. [Figure 5] 1 shows the results of the oil resistance test of Example 2, where the dye is applied onto the inside surface of the three-dimensional shaped article. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to a cellulose-based three-dimensionally shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the three-dimensionally shaped substrate comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

[0016] definition In the context of the present invention, the following definitions and test methods apply.

[0017] As used herein, the term "fiber" refers to a material form characterized by a very high length-to-diameter ratio. Generally, cellulose fibers have a very wide range of diameters and lengths depending on the fiber type and fiber source. The average length of wood pulp fibers preferably used in the present invention is typically in the range of 0.3 mm to 3.5 mm, preferably 0.3 mm to 3.0 mm, more preferably 0.8 mm to 2.5 mm, and even more preferably 1.0 mm to 2.0 mm. The diameter of wood pulp fibers is typically in the range of 10 μm to 40 μm, preferably 15 μm to 35 μm, and even more preferably 20 μm to 30 μm. Therefore, the aspect ratio (ratio of fiber length to fiber diameter) of wood pulp fibers is typically in the range of 7.5 to 350, preferably 7.5 to 300, more preferably 10 to 200, and even more preferably 20 to 150. The terms "fiber" and "filament" can be used interchangeably for purposes of the present invention, unless otherwise specified.

[0018] The term "cellulose-based" describes a substrate and / or material and / or article that substantially comprises cellulose. The material may be a fiber or a film. Cellulosic materials are derived from man-made sources, such as regenerated cellulose fibers or films, or from natural sources, such as fibers or pulp from woody or non-woody plants. Cellulose-based materials may comprise woven or non-woven cellulose. Non-woven cellulose-based materials may be formed from many processes, such as, for example, spin laying, carding, air laying, and wet-laying processes. The basis weight of a cellulose-based material is typically measured as weight per unit area, e.g., grams per square meter (gsm = g / m 2 ) or ounces per square foot (osf). Cellulose-based materials can include natural cellulosic fibers and / or non-fibrous cellulosic materials.

[0019] A "three-dimensionally shaped" substrate is a substrate that has been at least partially prepared by at least one three-dimensional shaping step.

[0020] The term "natural cellulosic fibers" refers to cellulose fibers from natural sources, such as woody plants, including deciduous and coniferous trees, or non-woody plants, including cotton, flax, esculenta, kenaf, sisal, abaca, milkweed, straw, jute, hemp, and bagasse. Preferably, the natural cellulosic fibers are suitable for dissolution by a gelatinizing agent. Suitable fibers for dissolution include, for example, hardwood fibers, softwood fibers, or annual plant fibers. Natural cellulosic fibers form crystalline materials, including a crystallized fraction with the crystalline morphology of cellulose I, which contains all parallel-oriented cellulose chains.

[0021] The term "non-fibrous cellulosic material" refers to a material obtainable by reacting natural cellulosic fibers with a gelatinizing agent, thereby at least partially dissolving the natural cellulosic fibers, which disintegrate to form a gelatinized viscous material, and then removing the gelatinizing agent by washing with a re-precipitation agent, thereby precipitating the gelatinized material to form a solid material. One process for dissolving natural cellulosic fibers and re-precipitating them is referred to as the parchmentation process. The solid material referred to herein as non-fibrous cellulosic material is predominantly amorphous and may contain other forms of crystallized fractions, such as a crystallized fraction having the cellulose II crystalline morphology, which contains antiparallel cellulose chains. The non-fibrous cellulosic material is preferably a re-precipitated gelatinized cellulosic material.

[0022] For ease of reference, the term "three-dimensionally shaped substrate" refers to a cellulose-based three-dimensionally shaped substrate according to the first aspect of the present invention, unless further specified.

[0023] In one embodiment, the three-dimensional shaped substrate comprises a composite material comprising natural cellulosic fibers and non-fibrous cellulosic materials. The substrate may be an article and / or a material.

[0024] In one embodiment, the natural cellulosic fibers and non-fibrous cellulosic material are contained in a continuous cellulosic fiber matrix. The term "continuous cellulosic fiber matrix" refers to a cellulosic material comprising natural cellulosic fibers and non-fibrous cellulosic material, where the natural cellulosic fibers are embedded in the non-fibrous cellulosic material, thereby blocking the pores of the fibrous framework. Thus, the continuous cellulosic fiber matrix represents a high-density material that provides a cellulose continuum between the natural cellulosic fibers and the non-fibrous cellulosic material, avoiding any voids at the interface between the natural cellulose fibers and the non-fibrous cellulosic material. Thus, the continuous cellulosic fiber matrix is ​​a continuous, non-porous material. The continuous cellulosic fiber matrix may have high gas barrier properties, particularly against oxygen.

[0025] In one embodiment, the continuous cellulosic fiber matrix further comprises destructured cellulosic fibers. The term "destructured cellulosic fibers" describes a periphery of native cellulosic fibers that have been partially dissolved with a gelatinizing agent, thereby producing a gradual structural change from native cellulose to precipitated cellulose. Such a gradual structural change means that the structure of the continuous cellulosic fiber matrix comprises a structural gradient, whereby the crystalline structure of the native cellulosic fibers slowly changes to the amorphous structure of the majority of the non-fibrous cellulosic material by forming destructured cellulosic fibers on the surface of the native cellulosic fibers. Thus, the destructured cellulosic fibers surround the native cellulosic fibers and are disposed between the native cellulosic fibers and the non-fibrous cellulosic material. Preferably, the continuous cellulosic fiber matrix can consist of native cellulosic fibers, destructured cellulosic fibers, and non-fibrous cellulosic material.

[0026] Cellulose-based three-dimensional substrate In step (i) of the first aspect of the present invention, a cellulose-based substrate precursor material is provided, comprising natural cellulosic fibers. For ease of reference, the terms "precursor material" and "cellulose-based substrate precursor material" are used interchangeably herein. The precursor material may comprise at least 50% natural cellulosic fibers, preferably at least 55% natural cellulosic fibers, more preferably at least 60% natural cellulosic fibers, more preferably at least 65% natural cellulosic fibers, more preferably at least 70% natural cellulosic fibers, more preferably at least 75% natural cellulosic fibers, more preferably at least 80% natural cellulosic fibers, more preferably at least 85% natural cellulosic fibers, more preferably at least 90% natural cellulosic fibers, and even more preferably at least 95% natural cellulosic fibers. In one embodiment, the precursor material is substantially or entirely composed of natural cellulosic fibers. Preferably, the precursor material comprises less than 1% by weight of non-fibrous cellulosic material. In one embodiment, the precursor material comprises 80% by weight or more wood pulp.

[0027] In one embodiment, the precursor material may be any of cardboard, waterleaf, absorbent paper, filter paper, and / or cellulosic tissue.

[0028] Step (ii) of the first aspect of the present invention comprises three-dimensional shaping of a cellulose-based substrate precursor and dissolving cellulose to produce a substrate having a three-dimensional shape comprising dissolved cellulose. In a preferred embodiment, the cellulose-based substrate precursor is the cellulose-substrate precursor provided in step (i).

[0029] In a preferred embodiment of the first aspect of the present invention, the cellulose dissolving step comprises at least partially infiltrating the cellulose-based substrate precursor material with a gelatinizing agent, thereby subjecting the cellulose-based substrate precursor material to reaction with the gelatinizing agent to dissolve the native cellulosic fibers and obtain an at least partially treated cellulose-based substrate precursor material.

[0030] As used herein, "partially wetted" means that only a portion of the natural cellulosic fibers in the precursor material are contacted with the gelatinizing agent, and the contacting is accomplished by wetting. In one embodiment, 0.1 to 99% by weight of the natural cellulosic fibers in the precursor material are contacted with the gelatinizing agent, more preferably 0.1 to 50% by weight, more preferably 0.1 to 40% by weight, more preferably 0.1 to 30% by weight, more preferably 0.1 to 20% by weight, more preferably 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, and even more preferably 0.5 to 3% by weight. In another embodiment, substantially all of the natural cellulosic fibers in the precursor material are contacted with the gelatinizing agent.

[0031] In one embodiment, the gelatinizing agent is provided in liquid form, e.g., a solution, and includes at least one cellulose solvent selected from the group consisting of inorganic acids including sulfuric acid and phosphoric acid, Lewis acids including ZnCl and Ca(SCN), inorganic bases including NaOH, organic bases including N-methylmorpholine N-oxide, and ionic liquids including tetraalkylammonium salts. Preferably, the gelatinizing agent includes sulfuric acid.

[0032] In one embodiment, the precursor material is porous and can absorb the gelatinizing agent, thereby resulting in wetting when the precursor material comes into contact with the gelatinizing agent. The degree of wetting can be controlled by controlling the porosity of the precursor material, controlling the thickness of the precursor material, controlling the basis weight of the precursor material, controlling the pressure of contact with the gelatinizing agent (e.g., roller marks), controlling the contact time between the precursor material and the gelatinizing agent (e.g., immersing the precursor material in the gelatinizing agent for a predetermined time), adding a reprecipitation agent, etc. Preferably, the degree of wetting is controlled by controlling the porosity and thickness of the precursor material, as further described below.

[0033] After at least partial infiltration with a gelatinizing agent according to a preferred embodiment of the first aspect of the present invention, the precursor material is subjected to a reaction with the gelatinizing agent to dissolve the native cellulosic fibers and obtain an at least partially processed cellulose-based substrate precursor material. The reaction can be a chemical reaction. The extent to which the gelatinizing agent dissolves the native cellulosic fibers depends on the extent of infiltration, as the gelatinizing agent dissolves fibers with which it directly contacts. Furthermore, the extent to which the reaction occurs depends on the nature and concentration of the gelatinizing agent. For example, if 10% by weight of the precursor material is infiltrated with the gelatinizing agent, the gelatinizing agent may dissolve 10% by weight or less of the native cellulosic fibers in the precursor material. In one embodiment, the gelatinizing agent reacts with substantially all of the native cellulosic fibers with which it directly contacts, thereby dissolving all of the native cellulosic fibers with which it directly contacts. The reaction with the gelatinizing agent, and thus the dissolution of the native cellulosic fibers, results in an at least partially processed cellulose-based substrate precursor material. Thus, the at least partially processed cellulose-based substrate precursor material comprises native cellulosic fibers and dissolved cellulosic fibers, the dissolved cellulosic fibers being a gel-like viscous material. Preferably, the at least partially processed cellulose-based substrate precursor material also comprises destructured cellulosic fibers. In one embodiment, the at least partially processed cellulose-based substrate precursor material is substantially processed.

[0034] In a further preferred embodiment of the first aspect of the present invention, the reprecipitation step comprises subjecting the at least partially treated cellulose-based substrate precursor material to a reprecipitation agent. In one embodiment, all of the dissolved cellulosic fibers are subjected to the reprecipitation agent. In another embodiment, only a portion of the dissolved cellulosic fibers are subjected to the reprecipitation agent. Preferably, at least the dissolved cellulosic fibers are subjected to the reprecipitation agent.

[0035] The reprecipitation agent removes the gelatinizing agent, thereby interrupting the reaction between the gelatinizing agent and the native cellulosic fibers. Thus, the gelatinized viscous material containing the dissolved cellulosic fibers precipitates into a solid material, referred to herein as a "non-fibrous cellulosic material." The non-fibrous cellulosic material may be dry or wet. Preferably, the non-fibrous cellulosic material, together with the destructured cellulosic fibers, forms a continuous cellulosic fiber matrix.

[0036] In one embodiment, the reprecipitation agent is water. In such embodiments, "removing the gelatinization agent" means diluting and washing away the gelatinization agent. Other reprecipitation agents that remove the gelatinization agent in other ways, for example, by neutralizing or otherwise inactivating the gelatinization agent, may be used.

[0037] In a further preferred embodiment of the first aspect of the present invention, the method may further comprise step (iv), wherein the three-dimensionally shaped substrate is further fixed by a drying step. Optionally, step (iv) may further comprise a separate washing step before the drying step.

[0038] The precursor material may be provided in any of the following forms: dry or wet cellulosic pulp or other forms of cellulosic fibers, loose cellulosic material, cellulosic sheets, woven fibers, nonwoven fibers such as fibers provided by a dry-laying or wet-laying process, knitted fibers or fibers assembled in the form of a sheet by any suitable process, and / or a three-dimensional shaped precursor article. In a preferred embodiment, the nonwoven process may be a wet-laying process such as a water or foam-forming process, or a dry-laying process such as an air-laying process. A three-dimensional shaped precursor article is considered to have undergone at least one three-dimensional shaping step.

[0039] In one embodiment, a three-dimensional shaping step of the substrate precursor material precedes the cellulose dissolution step of step (ii). In this embodiment, the three-dimensional shaping step results in a three-dimensional shaped precursor article on which the cellulose dissolution step is performed to form a substrate having a three-dimensional shape comprising dissolved cellulose. The three-dimensional shaped precursor article may also be considered a precursor material. Multiple three-dimensional shaping steps may be performed.

[0040] In one embodiment, the three-dimensional shaping of the substrate precursor material is carried out simultaneously with the cellulose dissolving step of step (ii). For example, the three-dimensional shaping can be carried out while the substrate precursor material is infiltrated with the gelatinizing agent.

[0041] In one embodiment, the precursor material provided in step (i) is provided in the form of a substrate precursor article. For ease of reference, the terms "substrate precursor article" and "precursor article" are used interchangeably herein.

[0042] In one embodiment, the precursor material provided in step (i) is provided in the form of a substrate precursor article having at least one surface region and a core region, and the gelatinizing agent is infiltrated into the at least one surface region in step (ii). After infiltration of the at least one surface region, the precursor article is subjected to a reprecipitation agent, such that the at least one surface region comprises a non-fibrous cellulosic material. Preferably, after exposure to the reprecipitation agent, the at least one surface region comprises a continuous cellulosic fiber matrix.

[0043] In one embodiment, the gelatinizing agent completely infiltrates the precursor article, ie, substantially infiltrates the entire surface and the core region.

[0044] In one embodiment, the gelatinizing agent does not infiltrate the core region, in which case the native cellulosic fibers within the core region remain intact and do not dissolve.

[0045] The at least one surface region is located substantially at the surface of the article, and the core region is located substantially at the majority of the article.

[0046] In one embodiment, the surface area penetrates at most 50%, more preferably at most 40%, more preferably at most 30%, more preferably at most 20%, more preferably at most 10%, more preferably at most 5%, more preferably at most 1%, and even more preferably at most 1% of the total thickness of the article.

[0047] In one embodiment, the surface area penetrates at most 5 cm into the article, more preferably at most 3 cm into the article, more preferably at most 1 cm into the article, more preferably at most 0.1 cm into the article, more preferably at most 1 mm into the article, more preferably at most 100 μm into the article, more preferably at most 50 μm into the article, and even more preferably at most 10 μm into the article.

[0048] The surface region may cover the entire surface of the precursor article or only a portion thereof. The portion of the surface not covered by the surface region is referred to herein as the "remaining surface." For example, in one embodiment, the precursor article is a three-dimensionally shaped precursor article that is concave, and the surface region covers only the inner surface of the concave three-dimensionally shaped precursor article. Thus, the outer surface of the concave three-dimensionally shaped precursor article is the remaining surface. In another embodiment, the three-dimensionally shaped precursor article is a cubic article, such as a box, and the surface region covers only one face. Thus, the other five faces constitute the remaining surface.

[0049] Controlling the infiltration of the gelatinizing agent into at least one surface region can be achieved by any suitable method. For example, the gelatinizing agent contacts only the surface region and not the remaining surfaces. This can be achieved, for example, by immersing the surface region in a solution containing the gelatinizing agent. Alternatively, the gelatinizing agent can be surface-applied to only one side of the sheet, for example, by rolling, spraying, kiss coating, transfer coating, and / or metered size pressing. The degree of infiltration can be controlled by controlling the porosity of the precursor article, controlling the thickness of the precursor article, controlling the basis weight of the precursor article, controlling the pressure of contact with the gelatinizing agent (e.g., roller marks), controlling the contact time between the precursor material and the gelatinizing agent (e.g., immersing the precursor material in the gelatinizing agent for a predetermined time), adding a reprecipitation agent, etc. Preferably, the degree of infiltration is controlled by controlling the porosity and thickness of the precursor article, as described in more detail below.

[0050] In one embodiment, the precursor material provided in step (i) is provided in the form of a precursor article which is a multi-layer or single layer article. A multi-layer article may be a multi-layer sheet consisting of several layers stacked vertically on top of each other.

[0051] In one embodiment, the multilayer precursor article can include a first layer and a second layer, where the first layer is disposed on the surface of the article and is more permeable to the gelatinizing agent than the second layer. Preferably, at least the first and second layers are made of a cellulose-based material. The permeability of the layers can depend, for example, on the basis weight / density and / or Bendtsen porosity of the layers. As a result, the gelatinizing agent penetrates deeper into the first layer and reacts more strongly with the native cellulosic fibers. Thus, when the multilayer precursor article is subjected to a reprecipitation agent, the first layer contains more non-fibrous cellulosic material than the second layer. Preferably, when the multilayer precursor article is subjected to a reprecipitation agent, the first layer contains a more continuous cellulosic fiber matrix.

[0052] In one embodiment, the second layer is substantially impermeable to the gelatinizing agent. Thus, after step (iii), the second layer does not contain non-fibrous cellulosic material and / or a continuous cellulosic fiber matrix. Preferably, the first layer contains more than 90% by weight of a continuous cellulosic fiber matrix, and the second layer contains less than 10% by weight of a continuous cellulosic fiber matrix.

[0053] In one embodiment, the second layer is disposed on the surface of the precursor article. In another embodiment, the second layer is disposed beneath the first layer throughout substantially the majority of the article. The precursor article may include an additional layer as the second layer, which may be more permeable, less permeable, or equally permeable to the gelatinizing agent.

[0054] In one embodiment, the precursor material provided in step (i) has a basis weight of at least 30 gsm, preferably at least 50 gsm, more preferably at least 70 gsm, more preferably at least 90 gsm, more preferably at least 100 gsm, more preferably at least 120 gsm, more preferably at least 140 gsm, more preferably at least 160 gsm, more preferably at least 180 gsm, more preferably at least 200 gsm, more preferably at least 220 gsm, more preferably at least 240 gsm, more preferably at least 260 gsm, and even more preferably at least 270 gsm. The precursor material may have a basis weight of less than 100 gsm, but the precursor article, whose barrier properties and recovery rate may be affected, may have the same basis weight. Basis weight is preferably determined according to ISO 536:1995.

[0055] In one embodiment, the precursor material provided in step (i) is provided in the form of a precursor article that is a multilayer article, the multilayer article comprising a first layer and a second layer, the first layer being disposed on a surface of the article, the first layer having a basis weight of at most 270 gsm, more preferably at most 260 gsm, more preferably at most 240 gsm, more preferably at most 220 gsm, more preferably at most 200 gsm, more preferably at most 180 gsm, more preferably at most 160 gsm, more preferably at most 140 gsm, more preferably at most 120 gsm, more preferably at most 100 gsm, more preferably at most 80 gsm, more preferably at most 60 gsm, more preferably at most 40 gsm, and even more preferably at most 20 gsm. The basis weight of the first layer may be as low as 6 gsm.

[0056] In one embodiment, the precursor material provided in step (i) has a Bendtsen porosity of 2000 ml / min or less, preferably 1500 ml / min or less, more preferably 1000 ml / min or less, more preferably 900 ml / min or less, more preferably 800 ml / min or less, more preferably 700 ml / min or less, more preferably 600 ml / min or less, more preferably 500 ml / min or less, more preferably 400 ml / min or less, more preferably 300 ml / min or less, more preferably 200 ml / min or less, and even more preferably 100 ml / min or less. The precursor article may have the same Bendtsen porosity. The Bendtsen porosity is preferably measured according to ISO 5636-3:2013.

[0057] In one embodiment, the precursor material provided in step (i) has a thickness of 1500 μm or less, more preferably 1000 μm or less, and even more preferably 800 μm or less. The precursor material provided in step (i) preferably has a thickness of at least 10 μm. More preferably, the precursor material provided in step (i) has a thickness of at least 50 μm, more preferably at least 100 μm, more preferably at least 200 μm, and even more preferably at least 300 μm. The precursor articles may have the same thickness. The thickness is preferably measured according to TAPPI T 411.

[0058] Bendtsen porosity and thickness can be used in combination to control the degree of gelatinizing agent infiltration. Three-dimensionally shaped substrates prepared from precursor materials and / or articles with relatively high Bendtsen porosity are believed to be less recyclable (but have relatively high barrier properties) than three-dimensionally shaped substrates prepared from precursor materials and / or articles with less porosity. Also, three-dimensionally shaped substrates prepared from precursor materials and / or articles with relatively high thickness are believed to be more recyclable than three-dimensionally shaped substrates with lower thickness. Therefore, preferably, the Bendtsen porosity and thickness of the substrate material and / or article are configured to achieve optimal barrier and / or recyclability performance.

[0059] In one embodiment, the precursor material has a Bendtsen porosity of 2000 ml / min or less and a thickness of 10 to 1500 μm, preferably a Bendtsen porosity of 1500 ml / min or less and a thickness of 50 to 1000 μm, and even more preferably a Bendtsen porosity of 1000 ml / min or less and a thickness of 100 to 800 μm. In a particularly preferred embodiment, the precursor material has a Bendtsen porosity of 200 to 1000 ml / min and a thickness of 300 to 800 μm. The precursor article can have the same combinations of porosity and thickness.

[0060] In one embodiment, the precursor material provided in step (i) is provided in the form of a precursor article that is a multi-layer article, the multi-layer article comprising a first layer and a second layer, the first layer being disposed on a surface of the article, and the first layer having a Bendtsen porosity of at least 100 ml / min, more preferably at least 200 ml / min, more preferably at least 300 ml / min, more preferably at least 400 ml / min, more preferably at least 500 ml / min, more preferably at least 600 ml / min, more preferably at least 700 ml / min, more preferably at least 800 ml / min, more preferably at least 900 ml / min, and even more preferably at least 1000 ml / min. In one embodiment, the second layer has a Bendtsen porosity of at most 500 ml / min, even more preferably at most 400 ml / min, even more preferably at most 300 ml / min, even more preferably at most 200 ml / min, even more preferably at most 100 ml / min, even more preferably at most 50 ml / min, and even more preferably at most 30 ml / min. The permeability of the layers correlates with their porosity. Thus, preferably, the porosity of the first and second layers is configured such that the first layer has a higher Bendtsen porosity than the second layer. Preferably, the first layer also has a lower thickness than the second layer, and preferably, the thickness of the first layer is at least 10 μm. In one embodiment, the thickness of the first layer is less than 50% of the total thickness of the first and second layers. Preferably, the thickness of the first layer is less than 40%, more preferably less than 30%, more preferably less than 20%, more preferably less than 10%, more preferably less than 5%, more preferably less than 3%, and even more preferably less than 1% of the total thickness of the first and second layers. The thickness of the first layer is preferably at least 0.0001% of the thickness of the first and second layers.

[0061] In one embodiment, the three-dimensional shaping of the precursor material is a three-dimensional shaping of a cellulosic sheet. The three-dimensional shaping of the cellulosic sheet may be any of thermoforming, wet-forming, wet-pressing, and / or cold-pressing. In a preferred embodiment, the three-dimensional shaping may be wet-forming or thermoforming.

[0062] For example, in one embodiment, a precursor material in the form of a cellulose-based sheet is three-dimensionally shaped to prepare a precursor article having a concave three-dimensional shape. In such a precursor article having a concave three-dimensional shape, the surface region may, for example, cover the internal cavity. The surface region may then be infiltrated with a gelatinizing agent, while the core region may remain untouched by the gelatinizing agent. Thus, a substrate having a three-dimensional shape containing dissolved cellulose in this embodiment will contain only dissolved cellulose in the surface region within the internal cavity. After being subjected to a re-precipitation agent, the three-dimensionally shaped substrate may then contain non-fibrous cellulose material only in the surface region covering the internal cavity. Preferably, after being subjected to a re-precipitation agent, the three-dimensionally shaped substrate may then contain a continuous cellulose fiber matrix only in the surface region covering the internal cavity.

[0063] In one embodiment, the three-dimensional forming of the precursor material is a three-dimensional forming of cellulosic pulp, which can be any of vacuum forming, dry pulp forming, transfer forming, and / or wet forming.

[0064] In one embodiment, the three-dimensional shaped substrate is recyclable by repulping, and at least 50% by weight is recoverable in accordance with EN 13430. The term "repulping" describes a process in which a material that has previously undergone or is formed by at least one pulping step is subjected to a further pulping step. The term "recyclable by repulping" describes a material that can be at least partially recovered during a repulping step and transformed into a new material or object. The material may be waste. The term "recyclable" is generally described in accordance with EN 13430. Thus, the phrase "recyclable by repulping, and at least 50% by weight is recoverable in accordance with EN 13430" describes a material that has been formed by or otherwise undergoes at least one pulping step, and from which at least 50% by weight of the three-dimensional shaped substrate can be recovered when subjected to a further pulping step.

[0065] In one embodiment, the three-dimensional shaped substrate is recyclable by repulping, and at least 55% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, more preferably at least 60% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, more preferably at least 65% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, at least 70% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, more preferably at least 75% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, more preferably at least 80% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, more preferably at least 85% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430, and even more preferably at least 90% by weight of the three-dimensional shaped substrate is recoverable according to EN 13430.

[0066] In one embodiment, the natural cellulosic fibers contained in the three-dimensional substrate are recycled by repulping. In one embodiment, the weight percent amount of the three-dimensional substrate that can be recovered during recycling by repulping is at most the amount of natural cellulosic fibers in the three-dimensional substrate. That is, all or most of the non-gelatinized cellulosic fibrous material that can be recovered during recycling by repulping can be considered as recoverable natural cellulosic material in the sense of the present invention. Therefore, natural cellulosic material also includes fibers that have not reacted with a gelatinizing agent, or that have at most been partially reacted. In this sense, "partial" reaction defines a situation in which the fibers are essentially able to maintain their fibrous state.

[0067] In one embodiment, the three-dimensional shaped substrate is at least 90% by weight, preferably at least 95% by weight, and more preferably 100% by weight, compostable according to EN 13432 and / or ASTM D6400. The term "compostable" is generally defined according to the EN 13432 standard. The term "compostable substrate" refers to a substrate in which at least 90% of the material must be biologically decomposed within six months under standard test method conditions, thereby meeting EN 13432. When applied to a material or product, the term "compostable" refers to the biodegradation and disintegration of the entire material or product. "Biodegradation" refers to the breakdown of a chemical structure or material under the action of microorganisms, while "disintegration" refers to the physical breakdown of a material or product made therefrom into small, visually indistinguishable fragments at the end of a typical composting cycle. To be considered a compostable polymeric material, the polymer chains must be degraded under the action of microorganisms so that total mineralization (i.e., conversion of the material into CO2, water, inorganic compounds, and biomass under aerobic conditions) is achieved at a high rate compatible with the normal composting process of vegetable waste.

[0068] In one embodiment, the three-dimensional shaped substrate is fully compostable. In one embodiment, the portion of the three-dimensional shaped substrate that is not recoverable by recycling through repulping is at least 90% by weight compostable according to EN13432 and / or ASTM D6400.

[0069] In one embodiment, the three-dimensional shaped substrate does not include plastic.

[0070] In one embodiment, the three-dimensional shaped substrate is food contact approved according to any of EU 1935 / 2004, BfR 36, BfR 36-1, BfR 36-2, FDA 21 CFA §176-170 and 176-180.

[0071] In one embodiment, the three-dimensional shaped substrate is oil resistant according to TAPPI T454.

[0072] In one embodiment, the three-dimensional shaped substrate is waterproof as determined according to TAPPI T441 at 30 seconds watertight, preferably at 60 seconds watertight, more preferably at 180 seconds watertight, more preferably at 300 seconds watertight, more preferably at 600 seconds watertight, and even more preferably at 1800 seconds watertight.

[0073] In one embodiment, the three-dimensional shaped substrate is 200 cm 3 / (m 2 × days), more preferably 180 cm 3 / (m 2 × days), and even more preferably, 160 cm 3 / (m 2 × days), and even more preferably, 140 cm 3 / (m 2 × days), and even more preferably, 120 cm 3 / (m 2 × days), and even more preferably, 120 cm 3 / (m 2 × days), and even more preferably, 100 cm 3 / (m 2× days), and even more preferably, 80 cm 3 / (m 2 × days), and even more preferably, 60 cm 3 / (m 2 × days), and even more preferably, 40 cm 3 / (m 2 × days), and even more preferably, 20 cm 3 / (m 2 x days) Oxygen transmission rate is measured according to ASTM D3985 and ASTM F 1927 at 23°C and 50% relative humidity.

[0074] In one embodiment, the three-dimensional shaped substrate comprises only natural polymers. In the context of the present invention, natural polymers are naturally occurring non-petroleum-based polymers such as rayon and hyaluronic acid, starch or modified starch. The natural polymers may be formed by living organisms, extracted, or may be purely chemically or physically modified by subsequent processes to convert them into a desired shape or form. In a preferred embodiment, the three-dimensional shaped substrate does not contain petroleum-based synthetic polymer adhesives or pressure-sensitive adhesives.

[0075] In one embodiment, the three-dimensional substrate is a packaging article. The packaging article is an article configured to package a second article. The packaging article is not particularly limited in size and / or three-dimensional shape.

[0076] In one embodiment, the three-dimensional substrate is a food packaging article. In the food packaging article, the second article is a food or a food ingredient. The food packaging is not particularly limited and can be used to store food, such as oxygen-sensitive food. The packaging article can be selected from, for example, a beverage container, a coffee capsule, a coffee pad, an egg container, or a soup bowl.

[0077] In one embodiment, the packaging article may be selected from any of a cosmetic packaging article, a medical packaging article, or an electronics packaging article.

[0078] Method for preparing cellulose-based three-dimensionally shaped substrates In a second aspect, the present invention relates to a method for preparing a cellulose-based three-dimensionally shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the method comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

[0079] Steps (i) to (iii) may be further characterized as any of the embodiments relating to steps (i) to (iii) disclosed above. For example, in one embodiment, the re-precipitating agent in step (iii) is water. In addition, the method of the second aspect of the present invention may include a further step (iv) in which the three-dimensionally shaped substrate is further fixed by a drying step. Optionally, step (iv) may further include a separate washing step before the drying step.

[0080] Fabrication of cellulose-based three-dimensional substrates In a third aspect, the present invention relates to a method for processing a three-dimensionally shaped substrate according to the first aspect of the invention.

[0081] In one embodiment, the processing comprises any of printing, laminating, painting, spraying, bonding, gluing, varnishing, impregnating, dipping, and / or bonding.

[0082] In one preferred embodiment, the three-dimensional shaped substrate is a food packaging article and the processing comprises printing a label for the food packaging article.

[0083] Use of cellulose-based three-dimensional substrates In a fourth aspect, the present invention relates to the use of a cellulose-based three-dimensionally shaped substrate according to the first aspect of the invention.

[0084] In one embodiment, such uses may be directed to any of the shipping, storage, protection, preservation, and / or presentation of packaged items (e.g., gift wrapping).

[0085] In one embodiment, the packaging use is directed to food packaging, cosmetic packaging, medical product packaging, and / or electronics packaging.

[0086] Based on the foregoing discussion, the examples below, and without wishing to be bound by theory, the inventors believe that this problem has been solved by providing a substrate with a three-dimensional shape that allows the advantageous barrier properties of parchment to be maintained. [Example]

[0087] Grade 30 cellulose extracted thimbles were prepared by vacuum forming from pure cellulose pulp. Egg containers were prepared by a transfer molding process.

[0088] Gelatinizing agent: sulfuric acid with a concentration of 70% to 75%.

[0089] Immersion method: The sample was immersed in a bath containing a gelatinizing agent for 6 seconds.

[0090] Imaging method: Scanning electron microscope (SEM) and / or digital photography

[0091] Bendtsen porosity was measured according to ISO 5636-3:2013.

[0092] Beck smoothness was measured according to ISO 5627:1995.

[0093] The thickness was measured according to TAPPI T 411.

[0094] Basis weight is determined in accordance with ISO 536:1995.

[0095] Oil resistance testing was performed according to Tappi T-454:2015.

[0096] The recyclability test was carried out according to EN 13430. A given sample was cut into approximately 25 cm 2 The repulped samples were screened on a Somerville-type apparatus using a 0.15 mm slot plate according to test method TAPPI / ANSI T 275 sp-18. The different recovered fractions were used to calculate the recoverable portion.

[0097] Example 1 A cellulose Soxhlet thimble (thickness: 1177 μm) having an open porous structure (Bendtsen porosity >5000 ml / min) and made from cotton fibers was prepared according to the method disclosed above. The thimble was then treated using a laboratory process in which one half of the thimble along its longitudinal axis was immersed in sulfuric acid for 6 seconds and then rinsed with water. Due to the open porous nature of the sample, the sulfuric acid completely infiltrated the immersed half of the sample, resulting in nearly complete parchmentation of this half of the sample (Figure 2, panels A-D).

[0098] The parchmented thimbles were then subjected to an oil resistance test. The specimens were cut in half along the long axis of the thimble, and an oil-based dye was spread inside according to Tappi T-454:2015. Therefore, it was confirmed that the dye penetrated only the untreated half of the thimble (Figure 3).

[0099] Example 2 Egg containers (thickness: 762 μm) made from recycled fibers with a dense, compact structure (Bendtsen porosity: 296 ml / min) and prepared according to the method disclosed above were provided. Egg containers are known to consist essentially of a lid and a base housing multiple egg-holding cavities (often six or ten). Two adjacent egg-holding cavities were then cut from the container and randomly labeled 1 and 2. The side labeled 1 was then immersed in sulfuric acid in a manner similar to Example 1. Due to the hard and dense nature of the sample, the sulfuric acid only partially infiltrated the immersed side 1 of the sample, resulting in only partial parchmentation on this side (Figure 4, panels A-D). Therefore, only the concave inner and outer surfaces were parchmented, while the core remained untreated.

[0100] Both sides 1 and 2 were treated with an oil-based dye spread inside the egg-holding cavity as in Example 1 above, thus confirming that the dye penetrated only the outer surface of the untreated side 2 (Figure 5).

[0101] The egg containers were then subjected to recyclability testing. In the untreated containers, 99.8% of the fibers were recoverable for recycling by repulping. In the treated material, 85.5% of the fibers were recoverable for recycling by repulping.

Claims

1. 1. A cellulose-based three-dimensional shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, the substrate comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

2. the cellulose dissolving step comprises at least partially infiltrating the cellulose-based substrate precursor material with a gelatinizing agent, thereby subjecting the cellulose-based substrate precursor material to a reaction with the gelatinizing agent to dissolve the native cellulosic fibers and obtain an at least partially treated cellulose-based substrate precursor material, preferably The three-dimensionally shaped cellulose-based substrate of claim 1 , wherein the re-precipitation step comprises subjecting the at least partially treated cellulose-based substrate precursor material to a re-precipitation agent.

3. In step (ii), the three-dimensional shaping step of the cellulose-based substrate precursor material precedes the cellulose dissolution step; or The cellulose-based three-dimensionally shaped substrate according to claim 1 or 2, wherein in step (ii), the three-dimensional shaping step of the cellulose-based substrate precursor material is carried out simultaneously with the cellulose dissolution step.

4. the substrate precursor material provided in step (i) is provided in the form of a substrate precursor article having at least one surface region and one core region; The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 3, wherein said gelatinizing agent infiltrates said at least one surface region.

5. 5. The three-dimensionally shaped cellulose-based substrate of claim 1, wherein the substrate precursor material provided in step (i) is provided in the form of a substrate precursor article, the article being a multi-layer or a single-layer article.

6. the substrate precursor article is a multi-layer article including a first layer and a second layer, the first layer being disposed on a surface of the article; The cellulose-based three-dimensionally shaped substrate of claim 5 , wherein the first layer is more permeable to the gelatinizing agent than the second layer.

7. the three-dimensional shaping of the cellulose-based substrate precursor material is a three-dimensional shaping of a cellulose-based sheet, and optionally a thermoforming step; or The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 6, wherein the three-dimensional shaping step of the cellulose-based substrate precursor material is a three-dimensional shaping step of a cellulose-based pulp, and optionally a vacuum forming step and / or a dry pulp forming step.

8. The substrate is recyclable by repulping, with at least 50% by weight of said substrate being recoverable in accordance with EN 13430; and / or at least 90% by weight compostable according to EN 13432, and / or The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 7, which is approved for food contact according to any one of EU 1935 / 2004, BfR 36, BfR 36-1, BfR 36-2, FDA 21 CFA § 176-170 and 176-180.

9. The substrate is oil resistant according to TAPPI T454, and / or Waterproof to 60 seconds without leakage as determined in accordance with TAPPI T441; and / or 9. The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 8, having an oxygen transmission rate of less than 200 cm3 / (m2 x day) when determined at 23°C and 50% relative humidity.

10. 10. The three-dimensionally shaped cellulose-based substrate according to any one of claims 1 to 9, wherein the cellulose-based substrate precursor material provided in step (i) comprises 80% by weight or more of wood pulp.

11. The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 10, wherein the substrate comprises only natural polymers.

12. 12. The cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 11, wherein the substrate is a packaging article, preferably the substrate is any of a food packaging article, a cosmetic packaging article, a medical packaging article, or an electronics packaging article.

13. 1. A method for preparing a cellulose-based three-dimensionally shaped substrate comprising natural cellulosic fibers and non-fibrous cellulosic materials, comprising: (i) providing a cellulose-based substrate precursor material comprising natural cellulosic fibers; (ii) a three-dimensional shaping step of a cellulose-based substrate precursor material and a cellulose dissolution step to produce a substrate having a three-dimensional shape comprising dissolved cellulose; (iii) a reprecipitation step in which the dissolved cellulose is reprecipitated.

14. the cellulose dissolving step comprises at least partially infiltrating the cellulose-based substrate precursor material with a gelatinizing agent, thereby subjecting the cellulose-based substrate precursor material to a reaction with the gelatinizing agent to dissolve the native cellulosic fibers and obtain a partially processed cellulose-based substrate precursor material, preferably 14. The method for preparing a cellulose-based three-dimensionally shaped substrate according to claim 13, wherein the reprecipitation step comprises subjecting the partially processed cellulose-based substrate precursor material to a reprecipitation agent.

15. 15. A method for preparing a cellulose-based three-dimensionally shaped substrate according to claim 13 or 14, wherein the re-precipitating agent is water.

16. 16. The method for preparing a cellulose-based three-dimensionally shaped substrate according to any one of claims 13 to 15, wherein the method further comprises a step (iv) of fixing the three-dimensionally shaped substrate in a drying process.

17. A method for processing a three-dimensionally shaped cellulose-based substrate according to any one of claims 1 to 12, comprising the steps of: A method wherein the processing comprises any of printing, laminating, coating, painting, spraying, bonding, gluing, varnishing, impregnating, dipping, and / or bonding.

18. Use of a cellulose-based three-dimensionally shaped substrate according to any one of claims 1 to 12 for packaging, preferably for packaging food, electronics, cosmetics and / or medical products.

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