Method, formed multi-layer textile product, and uses thereof

Abstract

According to one aspect of the present invention, there is provided a method comprising the steps of forming a multi-layer foamed fibrous structure in a mold from foamed fibrous compositions, each of the foamed fibrous compositions comprising cellulose fibers, water, air, and at least one blowing agent; dehydrating the foamed fibrous structure; and hot-pressing the dehydrated structure to obtain a molded fibrous product, wherein the at least one blowing agent comprises at least one surfactant blowing agent and / or at least one polymeric blowing agent, and at least one of the foamed fibrous compositions comprises a hydrophobic agent.

Description

[Technical Field]

[0001] The present invention relates to molded textile products. [Background technology]

[0002] In known techniques for preparing molded textiles, foam is deposited in a tray-like mold equipped with a headbox. Due to the separate molding and pressing sequences, the molding and dewatering processes are slow, and the foam can spread unevenly within the mold. This method is primarily suited to products such as filters and insulators. The resulting structures, such as egg trays, typically have thick walls (>500 μm), are porous, and have an inhomogeneous, rough surface. Furthermore, foam molding creates larger pores within the molded textile structure than water molding, which inhibits the formation of internal and external barriers in the product. Furthermore, due to the electrically charged foam environment in the wet end, compatibility between the foaming agent and barrier additives is difficult to achieve.

[0003] Another known alternative is to prepare shaped textiles using water-forming processes, but these processes are only suitable for forming a single, substantially thin-walled layer at a time, making the process cumbersome when more complex structures, such as multi-layer structures, are desired. Furthermore, water-formed textiles often have a non-uniform structure, and floc formation increases significantly with increasing fiber length and raw material consistency, for example, when attempting to avoid excessive water use.

[0004] Barrier properties are known to be important for molded textile products, especially food packaging. However, the micro-roughness of the molded fiber surface obtained by molding and the natural water affinity of the fibers pose challenges in terms of barrier formation. To overcome this, molding processes typically require significantly larger amounts of sizing chemicals compared to similar functional products made from, for example, folded cardboard.

[0005] Furthermore, in the thermoforming process, the cure time available for the sizing is significantly shorter than in the conventional drying section of a paper and board machine, making it impossible to overdose the sizing.

[0006] Known techniques are deficient when it comes to producing demanding shapes such as variable thickness walls, thin walls, deep drawn walls, edged structures, and low friction surfaces.

[0007] It is an object of the present invention to provide improved molded textile products, in particular obtainable by foam molding processes. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] BfR XXXVI / 2. Paper and paperboard for baking purposes: https: / / www.bfr.bund.de / cm / 349 / XXXVI-2-Paper-and-Paperboard-for-Baking-Purposes.pdf Summary of the Invention

[0009] The invention is defined by the features of the independent claims. Some particular embodiments are defined in the dependent claims.

[0010] According to a first aspect of the present invention, there is provided a method comprising the steps of: forming a multi-layer foamed fibrous structure from foamed fibrous compositions in a mold, each foamed fibrous composition comprising cellulose fibers, water, air, and at least one blowing agent; dehydrating the foamed fibrous structure; and hot pressing the dehydrated structure to obtain a shaped textile product; wherein the at least one blowing agent comprises at least one surface-active blowing agent and / or at least one polymeric blowing agent, and at least one of the foamed fiber compositions comprises a hydrophobic agent.

[0011] According to a second aspect of the present invention there is provided a shaped textile product obtained by the method according to the first aspect.

[0012] According to a third aspect of the present invention there is provided the use of a product according to the second aspect as, or as part of, food or liquid packaging, a food or liquid serving product, or for packaging, serving, storing, preparing, cooking and / or heating food or liquid.

[0013] According to a fourth aspect of the present invention there is provided the use of a non-ionic polymer as a foaming agent and AKD as an internal sizing agent in the manufacture of a shaped textile or part thereof such as a layer thereof by a process comprising foam molding followed by hot pressing.

[0014] According to a fifth aspect of the present invention, there is provided a method comprising the steps of: forming a multi-layer foamed fibrous structure from the foamed fibrous composition in a mold; wherein each foamed fiber composition comprises cellulose fibers, water, air, and a foaming agent, and the foamed fiber structure is dehydrated, for example, after each layer is formed; hot pressing the dehydrated structure to obtain a shaped multi-layer textile product; In this method, at least two different blowing agents are applied, the at least two different blowing agents being independently selected from the group of surfactant blowing agents and polymeric blowing agents.

[0015] According to a sixth aspect of the present invention there is provided a shaped multi-layer textile product obtainable by the method according to the fifth aspect, which product is preferably a food or liquid packaging or food or liquid serving product, or part thereof.

[0016] Various embodiments of the first and fifth aspects may include one or more features from the following bulleted list.

[0017] Each layer is formed from a respective foamed fiber composition.

[0018] Each foamed fiber composition, independently of the others, comprises at least one surface-active foaming agent, such as an anionic surfactant, and / or at least one polymeric foaming agent, such as a non-ionic polymer.

[0019] The method uses at least two different blowing agents, such as at least three different blowing agents, such as at least four different blowing agents.

[0020] At least one of the foamed fiber compositions includes both a surfactant foaming agent and a polymeric foaming agent.

[0021] At least two foamed fiber compositions, for example at least three foamed fiber compositions, include both a surfactant foaming agent and a polymeric foaming agent.

[0022] At least two of the foamed fiber compositions include different foaming agents.

[0023] The total amount of blowing agent in each foamed fiber composition is in the range of 0.1 to 35 wt.%, for example 5 to 20 wt.%, for example 1 to 3 wt.%, for example 0.1 to 1 wt.%, calculated from the weight of dry fiber in the foamed fiber composition.

[0024] The total amount of anionic surfactant in the foamed fiber composition comprising anionic surfactant is at least 0.1 wt.%, such as at least 0.5 wt.%, for example at least 1 wt.%, for example 0.1-1 wt.% or 1-5 wt.%, calculated on the weight of dry fiber in the foamed fiber composition.

[0025] The foamed fiber composition for at least one fiber layer comprises at least 0.5 wt. %, such as at least 1 wt. %, for example at least 5 wt. %, for example 5-35 wt. %, of a nonionic polymer as a foaming agent, calculated on the weight of dry fibers in the fiber composition.

[0026] The foamed fiber composition for at least one fiber layer comprises at least 0.1 wt. %, such as at least 0.5 wt. %, for example at least 1 wt. %, for example 0.1-1 wt. % or 1-5 wt. %, of an anionic surfactant as a foaming agent, calculated on the weight of dry fibers in the fiber composition.

[0027] The amount of each blowing agent in the foamed fiber composition is up to 1% by weight calculated on the weight of dry fibers in the fiber composition.

[0028] The at least one non-ionic polymer is selected from the following group: polyvinyl alcohol (PVA), polyethylene glycol dodecyl ether (Brij), polyethylene glycol sorbitan monolaurate (Tween 20), PEG-6 lauramide (PEG refers to polyethylene glycol), alkyl polyglycosides (APG), such as alkyl polyglucosides, fatty alcohol ethoxylates, alkyl phenol ethoxylates, fatty acid ethoxylates, fatty amide ethoxylates, alkyl glycosides, such as alkyl glucosides, sugar-based non-ionic polymers, such as sorbitan alkanoates, sorbitan fatty acid esters (Span), and combinations thereof.

[0029] The at least one anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, α-olefin sulfonates, alkyl sulfates, alkyl benzene sulfonates, alkyl ether sulfates, taurates, isethionates, and combinations thereof.

[0030] The at least one anionic surfactant comprises or consists of sodium dodecyl sulfate.

[0031] The at least one non-ionic polymer comprises or consists of PVA.

[0032] The foamed fiber composition for at least one fiber surface layer of the product comprises at least 0.5% by weight, such as at least 1% by weight, for example 1-50% by weight, of polyvinyl alcohol, calculated on the weight of dry fibers in the fiber composition.

[0033] The foamed fiber composition for at least one inner fiber layer of the product comprises at least 0.5% by weight, such as at least 1% by weight, for example 1-50% by weight, of polyvinyl alcohol, calculated on the weight of dry fibers in the fiber composition.

[0034] The foamed fiber composition comprises a nonionic polymer and an anionic surfactant in a molar ratio of 5:95 to 50:50, such as 10:90 to 30:70.

[0035] At least two, such as at least three, of the foamed fiber compositions further include a hydrophobic agent or a sizing agent.

[0036] At least one of the foamed fiber compositions does not include any hydrophobic agent or sizing agent.

[0037] The hydrophobic agent is contained in at least the last formed fibrous layer.

[0038] The hydrophobic agent is contained in at least the upper fibrous layer.

[0039] The hydrophobic agent is contained in at least the inner fabric layer.

[0040] All inner fibrous layers of the product preferably contain a hydrophobic agent to impart barrier properties, such as water resistance, to the product.

[0041] All fibrous layers of the product preferably contain a hydrophobic agent to impart barrier properties, such as water resistance, to the product.

[0042] The hydrophobic agent is an alkyl ketene dimer (AKD).

[0043] The foamed fiber composition for at least one fiber layer comprises at least 0.1 wt. %, such as 0.1 to 1 wt. %, for example 0.2 to 0.8 wt. %, of a hydrophobic agent, preferably AKD, calculated on the weight of dry fibers in the fiber composition.

[0044] The formed textile product comprises at least two fibre layers, for example two to five layers, for example exactly three fibre layers.

[0045] Each fibrous layer is formed by foam molding from a respective foamed fibrous composition, and preferably each composition, independently of the others, contains one or more foaming agents.

[0046] The foamed fiber composition for the upper and lower fiber layers comprises 1 to 50 weight percent of a nonionic polymer as a foaming agent, calculated on the weight of dry fiber in the fiber composition.

[0047] The foamed fiber composition for the intermediate or inner fiber layer contains 0.1 to 5% by weight of at least one anionic surfactant, calculated on the weight of dry fiber in the fiber composition.

[0048] The foamed fiber composition for at least one of the fibrous layers includes a surface active foaming agent, a hydrophobic agent, and a wet strength agent.

[0049] The foamed fiber composition for at least one of the fiber layers includes SDS, AKD, and PAE.

[0050] The foamed fiber composition for at least one of the fiber layers includes SDS and AKD.

[0051] The foamed fiber composition for at least one of the fiber layers includes PVA and AKD.

[0052] The cellulose fibers for the upper and lower fibrous layers are preferably refined to a Schopper-Riegler value of at least 20, such as at least 40, such as at least 50.

[0053] The cellulose fibers of the upper fibrous layer are refined to a Schopper-Riegler value of at least 40, such as at least 50.

[0054] The cellulose fibers of the lower fibrous layer are refined to a Schopper-Riegler value of at least 20, for example 20-40.

[0055] The resulting molded textile product is further coated or configured to be coated with a non-textile barrier coating layer that imparts water resistance, water vapor resistance, gas resistance such as oxygen resistance, and / or oil and grease resistance.

[0056] The cellulose fibers are composed of bleached or unbleached chemical pulp and / or bleached or unbleached chemi-thermomechanical pulp.

[0057] Each fiber layer is formed from a respective expanded fiber composition, preferably from expanded fiber compositions having different compositions, by a foaming process in a mold.

[0058] Each foamed fiber composition, independently of the others, comprises cellulosic fibers, water, air, and at least one foaming agent.

[0059] The foamed fiber composition of at least one fiber layer, such as the inner fiber layer, includes a surfactant foaming agent.

[0060] The foamed fiber composition of at least one fiber layer, such as for the fiber surface layer, includes a polymeric foaming agent.

[0061] The foamed fiber compositions for the fiber layers, such as the fiber surface layer, include both a surfactant and a polymeric foaming agent, and at least two of the foamed fiber compositions include different foaming agent selections or sets of foaming agents.

[0062] The total amount of blowing agent in each foamed fiber composition is in the range of 0.1 to 50 wt%, for example 0.1 to 20 wt%, for example 5 to 20 wt%, for example 1 to 3 wt%, for example 0.1 to 1 wt%, calculated from the mass of dry fiber in the foamed fiber composition.

[0063] The at least two blowing agents consist of two blowing agents.

[0064] The at least two blowing agents consist of or include three blowing agents.

[0065] The at least two foaming agents include PVA and sodium dodecyl sulfate.

[0066] The at least two foaming agents include polyethylene glycol dodecyl ether (Brij) and sodium dodecyl sulfate.

[0067] The at least two foaming agents include an anionic surfactant and two nonionic surfactants.

[0068] The foamed fiber compositions for at least the surface fiber layers, and preferably for all fiber layers, each contain an anionic surfactant and two nonionic surfactants.

[0069] The at least two foaming agents include polyethylene glycol dodecyl ether (Brij), sodium dodecyl sulfate, and PVA.

[0070] The foamed fiber composition for at least one fiber layer of the product comprises at least 10% by weight of polyvinyl alcohol, calculated on the weight of dry fibers in the fiber composition.

[0071] The foamed fiber composition for at least one of the fiber layers comprises a nonionic polymer and an anionic surfactant in a molar ratio of 5:95 to 50:50, such as 10:90 to 30:70.

[0072] The foamed fiber composition for at least one fiber layer comprises polyethylene glycol dodecyl ether and sodium dodecyl sulfate in a molar ratio of 5:95 to 50:50, for example, 10:90 to 30:70.

[0073] At least one of the foamed fibrous compositions, preferably that for the upper fibrous layer, further includes a hydrophobic or sizing agent, such as AKD.

[0074] The hydrophobic agent is contained in at least the last layer formed.

[0075] The foamed fiber composition for at least one fiber layer comprises at least 0.1 wt. %, for example 0.1 to 1 wt. %, for example 0.2 to 0.8 wt. %, of a hydrophobic agent, preferably AKD, calculated on the mass of dry fibers in the fiber composition.

[0076] The molded textile product comprises at least three layers of fiber.

[0077] Either or both of the foamed fiber compositions for the upper and lower fiber layers contain 1 to 50 weight percent of a nonionic polymer as a foaming agent, calculated on the weight of dry fiber in the fiber composition.

[0078] The foamed fiber composition for the inner fiber layer contains 0.1 to 5% by weight of an anionic surfactant, calculated on the mass of dry fiber in the fiber composition.

[0079] Either or both of the foamed fiber compositions for the upper and lower fiber layers contain 0.1 to 5 weight percent anionic surfactant, calculated on the weight of dry fiber in the fiber composition.

[0080] The foamed fiber composition for the inner fiber layer comprises 1 to 50 wt. % of a nonionic polymer as a foaming agent, calculated on the weight of dry fibers in the fiber composition.

[0081] The cellulosic fibers consist of or include wood pulp.

[0082] The hot pressing preferably includes two hot pressing steps with impulse drying.

[0083] The total hot pressing time (all hot pressing steps combined) is less than 2 minutes, for example less than 1 minute.

[0084] The foamed fiber composition for at least one fiber layer comprises 0.1 to 1 wt. %, for example 0.2 to 0.8 wt. %, of AKD, calculated on the weight of dry fibers in the fiber composition.

[0085] The molded fibrous article comprises at least three fibrous layers, and the foamed fibrous composition for at least one fibrous layer comprises SDS as a surfactant foaming agent, AKD as a hydrophobic agent, and PAE as a wet strength agent.

[0086] The molded textile product comprises at least three fibrous layers, wherein the foamed fibrous compositions for the upper and lower fibrous layers comprise a nonionic polymer as a foaming agent, the foamed fibrous composition of the inner fibrous layer comprises an anionic surfactant as a foaming agent, the foamed fibrous composition of the upper fibrous layer further comprises a hydrophobic agent such as a sizing agent, and / or the foamed fibrous composition of the lower fibrous layer further comprises a hydrophobic agent such as a sizing agent.

[0087] The molded textile product comprises at least three fibrous layers, wherein the foamed textile compositions for the upper and lower fibrous layers comprise an anionic surfactant as a foaming agent, the foamed textile composition for the inner fibrous layer comprises a nonionic polymer as a foaming agent, and the foamed textile composition for the inner fibrous layer further comprises a hydrophobic agent such as a sizing agent.

[0088] The foamed fibrous composition for at least one fibrous layer comprises a nonionic surfactant, such as a glucamide, optionally in combination with an anionic surfactant, such as SDS.

[0089] At least two of the foamed fiber compositions, independently of one another, comprise a nonionic surfactant, optionally in combination with an anionic surfactant.

[0090] Various embodiments of the second or sixth aspect may include one or more features from the following bulleted list.

[0091] The product comprises at least two layers of fibers, for example, two to five layers.

[0092] The product is a three-dimensional molded product.

[0093] The article may include a curved or non-planar surface.

[0094] The dry weight of each fiber layer is 30-700g / m 2 The range is.

[0095] The Shopper-Riegler number of the cellulose fibers in one or more inner fibrous layers of the product is less than 50, for example less than 30.

[0096] The cellulose fibers in the upper and / or lower fibrous layer of the product have a Shopper-Riegler number of at least 20, such as at least 40, for example at least 50. The cellulose fibers in the lower fibrous layer of the product have a Shopper-Riegler number of at least 20, for example 20-40.

[0097] The cellulose fibres in the upper fibrous layer of the product have a Schopper-Riegler number of at least 40, such as at least 50.

[0098] The product may be a food or liquid package or a food or liquid serving product, or part thereof, and preferably at least the upper fibrous layer adapted to contact the food or liquid comprises a hydrophobic agent to impart barrier properties.

[0099] The product is a thin-walled molded textile product obtained by a foam molding process, preferably having a variable or substantially constant thickness of less than 2 mm.

[0100] The surface of the product that is adapted to come into contact with food or liquids exhibits water and / or oil and grease resistance.

[0101] The surface of the product that is adapted to come into contact with food or liquid is coated or adapted to be coated with a non-fibrous barrier coating layer.

[0102] The non-fibrous barrier coating layer provides or enhances the water resistance, water vapor resistance, gas resistance such as oxygen resistance, and / or oil and grease resistance of the surface.

[0103] The thickness of the product is in the range of 300 to 1000 μm, for example 300 to 700 μm, for example 450 to 900 μm.

[0104] The Bendtsen smoothness of the product is in the range of 50-4000 ml / min, for example 100-1000 ml / min.

[0105] The tensile index of the product ranges from 25 to 60 Nm / g in the machine and cross directions.

[0106] The modulus of elasticity of the product ranges from 3.0 to 6.5 GPA in the machine and cross directions.

[0107] The bending stiffness (Taber 15°) of the product ranges from 40 to 80 mNm in the machine and cross directions.

[0108] The product is heat sealed with a thermoplastic material or is heat sealable with a thermoplastic material, such as a thermoplastic packaging material.

[0109] The cellulose fibers in one or more inner fibrous layers of the product have a Shopper-Riegler number of less than 30, the cellulose fibers in a lower fibrous layer of the product have a Shopper-Riegler number of 20 to 40, and the cellulose fibers in an upper fibrous layer of the product have a Shopper-Riegler number of at least 40.

[0110] Advantages of the Invention The present invention can provide an improved method for the internal sizing of molded textiles, especially multi-layer foam molded textiles.

[0111] The present invention is particularly advantageous for molded textile products that are intended to be coated, for example, with an aqueous barrier coating. Such coated products include, for example, barrier-coated food packaging. Some embodiments provide an effective method for adequately conditioning the internal sizing of such products.

[0112] Some embodiments may allow for optimization of the location of sizing chemicals within multi-layer molded textiles.

[0113] For surface modification of molded textiles, such as dispersion barrier coatings, the wettability of the molded fiber surface can be important, while too much hydrophobic structure from the internal sizing agent can prevent the formation of a coating film.

[0114] In some embodiments, the thermoplastic material may allow for improved heat sealability.

[0115] In some embodiments, using high loadings of sizing and additional chemicals in the inner layers, e.g., the middle layer, allows for the combination of inner and outer barriers by individually optimizing the foaming, sizing, and additional chemicals in each foam layer, potentially resulting in enhanced functionality in the molded textile.

[0116] In some embodiments, each layer can contain a different set of foaming agents and hydrophobic agents in combination with cellulose fibers, allowing for better tailoring and control of the properties of the final foamed product. In particular, the hydrophobicity and associated barrier effect can be limited to a desired portion / layer of the product, and the surfactant selection for each layer can be modified to be compatible with the presence or absence of a hydrophobic agent in that layer. Thus, the present invention may allow for better control and tailoring of the properties of the foamed product, particularly the barrier properties, while maintaining good foamability of the raw material.

[0117] The present invention avoids the need for a separate non-fibrous barrier coating layer and potentially avoids problems associated with coating adhesion.

[0118] The present invention avoids the use of a separate plastic barrier coating.

[0119] The present invention allows for the rapid production of multi-layer molded textile products, cycle times can be reduced, and wetting and rewetting of the product through separate coating steps can be avoided.

[0120] The present invention allows the properties of the individual layers to be easily tailored.

[0121] The product may have a more uniform distribution of cellulose fibers.

[0122] In the present invention, fiber clumping and cloudiness can be avoided or reduced.

[0123] The present invention can provide biodegradable, compostable, and recyclable multi-layer molded textile products suitable for food contact, such as ovenable and / or microwaveable products.

[0124] The present invention can reduce energy consumption, particularly when foam molding is used, due to the reduced need to dewater and dry the product.

[0125] The present invention reduces manufacturing costs associated with cycle times, dewatering, drying, and chemicals, and improves chemical retention, especially when foam molding is used.

[0126] The present invention can provide textiles with good internal barrier properties.

[0127] The present invention can provide textile products of complex shapes that are free from creases and cracks.

[0128] The present invention may be advantageous for the production of demanding shapes such as variable thickness or thin walls, deep drawn walls, edged structures, low friction surfaces, and the like.

[0129] The present invention can provide plastic-free textile packaging that can be recycled in existing textile recycling infrastructure.

[0130] The present invention can provide a biodegradable and / or compostable product.

[0131] The present invention has the potential to replace existing, often plastic-based, packaging solutions. [Brief explanation of the drawings]

[0132] [Figure 1] 1A and 1B illustrate schematic diagrams of multi-layer textile products in accordance with at least some embodiments of the present invention. [Figure 2] 1 shows a stereomicroscope image of the fiber structure. [Figure 3] 1 shows a stereomicroscope image of the fiber structure. [Figure 4] 1 shows a stereomicroscope image of the fiber structure. [Figure 5] 1 is a flowchart illustrating process steps for making a multi-layer foam molded product in accordance with at least some embodiments of the present invention. [Figure 6]1 illustrates foam molding of a three-layer fibrous structure in accordance with at least some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0133] definition Unless otherwise stated herein or apparent from the context, percentages referred to herein are expressed as weight percent based on the total dry weight of the respective composition.

[0134] The amount of additive is usually expressed as a weight percentage calculated from the weight of dry fiber in the respective composition.

[0135] In this context, the term "hot pressing" typically refers to a process that involves the application of elevated pressure and elevated temperature over a period of time. Hot pressing may involve multiple successive cycles or steps of increasing pressure and temperature. In some cases, hot pressing may involve the application of subatmospheric pressure. Typically, the goal of a hot pressing process is to obtain a strong, dimensionally stable product with a smooth product surface.

[0136] In this context, the term "molded article" refers to an article obtained by molding or giving a shape to an article in a closed or closable cavity of a mold. Generally, "molding" does not refer to simply pressing an article between two plates.

[0137] In the present context, the term "cellulosic fibrous material" may refer to a material that comprises cellulose and / or lignocellulosic fibers.

[0138] Generally, the terms "upper fibrous layer" or "topmost fibrous layer" refer to the fibrous surface layer that is closest to or in contact with the contents of the package, such as food.

[0139] Generally, the terms "lower fibrous layer" or "bottommost fibrous layer" refer to a fibrous surface layer located on the opposite side of the fibrous structure from the upper fibrous layer.

[0140] The term "surface active foaming agent" generally refers to a surfactant.

[0141] The products are typically three-dimensionally molded single or multi-layer textile products obtained using a foam molding process.

[0142] The present inventors have found that certain combinations of additives are advantageous when preparing fiber products formed by foam molding. The additives are typically added to the fiber slash, for example, before or after foaming the fiber slash, or before or after adding a foam composition to the fiber slash. In yet another embodiment, the additives are added to the structure after the foam molding step and before the hot pressing step.

[0143] In particular, the inventors have observed that internal sizing of foamed molded textiles, typically with a hydrophobic sizing agent, can be achieved successfully by using a specific combination of foaming agents, such as surfactants, and additives, such as retention aids, fixatives, and wet strength agents, in addition to the sizing agent.

[0144] Furthermore, the inventors have observed that the use of several foaming chemicals can be advantageous in the production of foamed, multi-layer textile products, with each layer of such a product being produced using an optimum combination of foaming chemicals and, if necessary, further additives.

[0145] At least one of the layers of the product is a fibrous layer comprising cellulosic fibrous material.

[0146] Cellulose fiber materials The cellulosic fibrous material may include wood pulp, such as hardwood pulp and / or softwood pulp.

[0147] Softwood pulp may be made from spruce, pine, or a mixture thereof.

[0148] Hardwood pulp is made from tropical hardwoods such as birch, poplar, aspen, alder, maple, eucalyptus, or mixtures thereof.

[0149] The wood pulp may be a mixture of hardwood and softwood pulp.

[0150] In one embodiment, the cellulosic fibrous material can include pulp made from any annual plant such as straw, reed, reed canary grass, bamboo, sugarcane, bagasse, or any grass plant.

[0151] In an embodiment, the cellulosic fibrous material comprises hardwood pulp and softwood pulp in a weight ratio ranging from 1:2 to 2:1.

[0152] The cellulosic fibrous material can include wood pulp selected from the following group: chemical pulp, mechanical pulp, and any combination thereof.

[0153] The cellulose fibrous material can include one or more of chemical wood pulp, mechanical wood pulp such as chemi-thermomechanical wood pulp, fibrillated cellulose such as microfibrillated cellulose (MFC), nanocellulose, and other cellulose materials comprising cellulose fibers or portions of cellulose fibers.

[0154] The MFC and nanocellulose may be of wood or non-wood origin.

[0155] Advantageously, at least one of the fibrous layers, e.g., the inner layer, comprises bleached chemi-thermomechanical wood pulp (BCTMP). The BCTMP can be refined to a Canadian Standard Freeness of less than 800 ml, e.g., 600-800 ml. The BCTMP can also be unrefined.

[0156] Cellulosic fibrous materials may also include non-wood pulps such as straw pulp.

[0157] In some embodiments, the cellulosic fibrous material comprises or consists essentially of virgin wood pulp, such as substantially lignin-free virgin bleached chemical pulp, making the product particularly suitable for food contact, e.g., cooking, heating, oven cooking, and microwave cooking.

[0158] In an embodiment, at least 80% by weight, such as at least 95% by weight, of the cellulosic fibrous material of the product consists of virgin cellulosic fibers, such as virgin wood pulp.

[0159] The advantage of virgin pulp is that it does not contain pigments or other undesirable chemicals. Recycled waste often contains chemical and microbiological contaminants that may affect its safe use. Mixtures of chemicals and microbial products can leach from recycled materials, causing various adverse health or environmental effects. Not only the harmfulness of individual chemicals, but also interactions with other chemicals and microbial products can increase the toxicity and emissions of recycled materials. Therefore, the present invention prefers to avoid the use of recycled materials.

[0160] In some embodiments, recycled materials may be used.

[0161] The advantage of chemical pulps, such as bleached chemical pulp, is that they contain very little lignin. An additional advantage of chemical pulps is that the bonds between fibers in the final product may be better than those in mechanical pulps.

[0162] Lignin-containing pulps often have insufficient organoleptic quality for direct food contact. Additionally, lignin-containing pulps are susceptible to aging and yellowing of the material.

[0163] foam molding Advantageously, one or more of the fibrous layers of the product are obtained by a foam moulding process.

[0164] Preferably, the multi-layer product is obtained in such a way that all fibers in the final structure undergo the foaming process, and in some embodiments, all fibers in the layer exhibiting barrier properties undergo the foaming process.

[0165] For example, a fibrous layer exhibiting at least barrier properties can be obtained by foaming in a mold. Such a fibrous barrier layer can be any fibrous layer, such as the top fibrous layer, the bottom fibrous layer, and / or one or more inner fibrous layers.

[0166] The advantage of foam molding is that it can produce lighter, bulkier products. Furthermore, it can produce more uniform moldings. Foams can easily be used to produce multi-layer structures in a modular process. That is, all layers can be molded in the same mold, but the composition and selection of fiber materials and additives for each layer are individually tailored to form a multi-layer shape or structure within the mold, which is then hot-pressed.

[0167] The advantage of dehydrating the entire multi-layer structure in the same mold is that the bonding between the layers may be stronger during dehydration compared to dehydrating the layers individually.

[0168] In some embodiments, in addition to the foamed layer, the final product may further include a water-formed layer. Such a water-formed layer may be formed in a separate process and combined with the foamed layer or foamed multi-layer structure by hot pressing. The advantage of water-forming is that no foaming chemicals are present and therefore do not interfere with the function of the sizing agent. In water-forming methods, individual layers are typically formed and removed from the mold independently of each other. Separate molds may be used. After removal from the mold, the layers may be stacked and bonded to each other and / or to other layers by hot pressing.

[0169] In some embodiments, the final product may further include a water-formed layer in addition to the foam-formed layer, and all layers, i.e., the water-formed layer and the foam-formed layer, are formed in the same mold to form a multi-layer shape or structure in the mold, which is then hot-pressed.

[0170] In one embodiment, the product comprises a plurality of fibrous layers prepared by a water-forming process, bonded together and optionally in addition to at least one foamed fibrous layer, which advantageously constitutes one or more inner fibrous layers, such as a middle layer, of the product and which advantageously exhibits barrier properties.

[0171] In embodiments, the product may include one or more water-formed layers and one or more foam-formed layers, in which the inner or inner fibrous layer is water-formed and the upper and lower fibrous layers are foam-formed.

[0172] An advantage of multilayer products according to some embodiments is that material migration can occur during molding and / or hot pressing. For example, the dosage of additives, such as sizing agents, can be concentrated or increased in the last layer prepared and molded, such as the upper fiber layer. During dewatering and / or hot pressing, material migration within the multilayer structure can be directed in a desired direction, for example, by pressure and / or temperature gradients.

[0173] One embodiment provides a product obtained by the following method.

[0174] In some embodiments, the product or at least one of its fibrous layers may be obtained by a method comprising the following steps: providing a fiber slush comprising fibers; refining the fibers of the fiber slush and / or adding additives such as barrier agents to the fiber slush; forming the fiber slush into a foam composition; a forming step, such as molding and pressing the foam composition in a mold; dehydrating, and Hot pressing process.

[0175] In some embodiments, the barrier agent or other additive may alternatively or additionally be added at a later stage in the process, for example, by applying a composition comprising the barrier agent to the fiber foam or to an already formed fiber layer, preferably a foamed layer.

[0176] The method includes first preparing a foam composition containing fibers, water, air, and one or more blowing agents. The foam composition may further contain fillers, additives, retention aids, fixatives, pigments, binders, strength agents, barrier dispersants, and / or sizing agents. The foam composition is then formed into a mold.

[0177] In an embodiment, the method includes forming a multi-layer foamed fibrous structure in a mold from each foamed fibrous composition comprising cellulose fibers, water, air, and at least one foaming agent; dewatering the foamed fibrous structure; and hot-pressing the dewatered structure to obtain a molded fibrous product. The at least one foaming agent comprises at least one surface-active foaming agent, such as an anionic surfactant, and / or at least one polymeric foaming agent, such as a nonionic polymer. Preferably, at least one of the foamed fibrous compositions comprises a hydrophobic agent.

[0178] In another embodiment, a method includes forming a multi-layer foamed fibrous structure in a mold from foamed fibrous compositions, each of which comprises cellulosic fiber, water, air, and a blowing agent, dehydrating the foamed fibrous structure, and hot-pressing the dehydrated structure to obtain a molded multi-layer fibrous product. In this method, at least two different blowing agents are applied. The at least two different blowing agents are independently selected from the group consisting of surfactant blowing agents and polymeric blowing agents.

[0179] Typically, different types of foamed fiber compositions are used to prepare each layer of a multi-layer product. Each foamed composition may contain a dedicated set of foaming agents and other additives, such as hydrophobic agents. By "different types," we mean having different compositions, such as different foaming agent and additive selections and / or different consistencies.

[0180] The foaming agent preferably comprises a surface active foaming agent, such as a surfactant, and / or a non-ionic polymeric foaming agent, or a mixture thereof.

[0181] Surfactants are typically molecules that have two parts: a polar or hydrophilic head group and a hydrophobic tail.

[0182] Gemini surfactants have two polar head groups connected by a spacer, making them anionic, nonionic, cationic, or zwitterionic.

[0183] In embodiments, the surfactant comprises a gemini surfactant.

[0184] In embodiments, the surfactant is degradable, for example, by a specific pH value or enzyme. The foaming properties of such degradable surfactants can be removed, if desired, by decomposition later in the manufacturing process, such as in the water cycle.

[0185] In an embodiment, the surfactant is at least partially, preferably fully, synthesized from renewable raw materials. The surfactant may be at least partially bio-based, for example 100% (fully) bio-based.

[0186] The surfactants can include zwitterionic surfactants selected from the following groups: betaines, amidobetaines, imidazolines, amide oxides, and combinations thereof. The advantages of these surfactants are that they are broadly compatible with other classes of surfactants and are generally stable to varying pH.

[0187] Each of the fibrous layers may independently use one or more foaming agents.

[0188] The surfactants can be nonionic, anionic, cationic or amphoteric.

[0189] The foam-forming surfactants may have anionic, nonionic, cationic, or zwitterionic polar head groups.

[0190] The surfactant may have a hydrocarbon tail that is straight, branched, or double chained.

[0191] For foam formation, hydrophilic surfactants with straight or double chain ends are preferred.

[0192] In embodiments, at least one anionic surfactant is used.

[0193] In an embodiment, at least one non-ionic polymer is used.

[0194] In some embodiments, at least one anionic surfactant and at least one nonionic polymer are used as foaming agents, particularly to improve foaming. For example, the anionic surfactant can be sodium dodecyl sulfate (SDS), and the nonionic polymer can be polyoxyethylene (23) lauryl ether or polyoxyethylene sorbitan fatty acid ester and sorbitan ester.

[0195] In embodiments, at least one hydrophilic surfactant and at least one lipophilic or hydrophobic foaming agent are used as foaming agents, for example, the hydrophilic surfactant may be Tween, a non-ionic hydrophilic surfactant, and the lipophilic foaming agent may be a sorbitan-based foaming agent.

[0196] A suitable amount of anionic surfactant is 0.2-5 g / L (grams per liter of fibrous stock).

[0197] A suitable amount of anionic surfactant is 1 to 20% by weight per dry fiber.

[0198] The anionic surfactant may be selected from the following group: sodium dodecyl sulfate (SDS), α-olefin sulfonate, alkyl sulfate, alkyl benzene sulfonate, alkyl ether sulfate, taurate, isethionate, and combinations thereof.

[0199] Examples of non-ionic foaming chemicals include non-ionic polymer foaming chemicals such as polyvinyl alcohol.

[0200] The non-ionic polymer may be selected from the following group: polyvinyl alcohol (PVA), polyethylene glycol dodecyl ether (Brij), polyethylene glycol sorbitan monolaurate (Tween 20), PEG-6 lauramide, alkyl polyglycosides (APG), such as alkyl polyglucosides, fatty alcohol ethoxylates, alkyl phenol ethoxylates, fatty acid ethoxylates, fatty amide ethoxylates, alkyl glycosides, such as alkyl glucosides, sugar-based non-ionic polymers, such as sorbitan alkanoates, and combinations thereof.

[0201] In some embodiments, the at least one foaming agent may be selected from anionic surfactants and nonionic surfactants.

[0202] In an embodiment, the foamed fibrous composition for at least one fibrous layer comprises an anionic surfactant, such as SDS, and a nonionic surfactant, such as a glucamide.

[0203] In an embodiment, the foamed fiber composition for at least one of the fiber layers comprises SDS and glucamide.

[0204] In an embodiment, the foamed fiber composition for at least one of the fiber layers comprises SDS and alkyl polyglycoside (APG).

[0205] In some embodiments, the at least one foaming agent may be selected from the group of SDS, alkyl polyglycosides (APGs), glycinates, glucamides, and any combination thereof.

[0206] The blowing agent, and more generally additives such as surfactants, may be arranged to be recycled in the process.

[0207] Typically, the cell size (diameter) within the foam is about 10 to 300 μm, for example 50 to 250 μm, typically about 100 to 150 μm.

[0208] In one embodiment, a composition suitable for foaming is obtained by mixing a fiber slush (fiber stock) having a consistency of about 0.5-7% by weight (amount of fiber relative to the weight of the slush) with a foam formed from water and a foaming agent and having an air content of about 10-90% by volume, such as 20-80% by volume, for example 50-70% by volume, to produce a foamed fiber slush having a fiber content of about 0.1-3% by weight.

[0209] In one embodiment, instead of mixing the fiber slush with pre-formed foam, a foaming agent can be added to the fiber slush and the mixture can then be foamed to obtain a foamed fiber slush. The mixture to be foamed typically has a consistency in the range of 0.5-3%, for example 1.0-2.5%.

[0210] For example, a fibrous slush of 0.5-7%, e.g., 1-3%, consistency is first prepared. Optionally, the pH of the fibrous slush is adjusted to greater than 7, e.g., 7-9. At least one foaming agent and, optionally, additives such as a wet strength agent are then added to the fibrous slush. For example, a wet strength agent such as PAE is added first, followed by a foaming agent such as a surfactant. The fibrous slush is then foamed, after which additional additives, typically a hydrophobic agent and / or a wet strength agent, are added to the foamed mixture.

[0211] Fibers include all types of fibers from chemical and / or mechanical pulping, recycled fibers, post-consumer fibers, agricultural waste, annual plant fibers, by-products, micro- or nanofibrillated cellulose fibers of wood or non-wood origin, regenerated cellulose fibers, and combinations thereof.

[0212] In one embodiment, the molded multi-layer fibrous product is obtained by a process comprising forming a molded multi-layer foam structure from at least one foamed fibrous composition comprising cellulose fibers, water, air, a blowing agent, and optionally barrier agents and additives, dewatering the structure, preferably by applying a vacuum, and hot-pressing the dewatered structure to obtain the molded multi-layer fibrous product. At least one of the fibrous layers of the multi-layer fibrous product may exhibit barrier properties throughout substantially the entire structure.

[0213] In the present context, "molding", typically foam molding, refers to the process of imparting a foam composition with a shape, such as a three-dimensional shape, within a mold.

[0214] In a preferred method, the foamed fiber composition is fed into a mold, typically a cavity within the mold. The mold typically includes a cavity or interior space defined by the interior surface of the mold. Within the cavity, the foamed composition is shaped. In the closed configuration of the mold, the dimensions of the cavity, e.g., its shortest dimension, may range from 0.1 to 100 mm, e.g., 3 to 100 mm, e.g., 5 to 60 mm.

[0215] The shortest or smallest dimension usually refers to the thickness of the product or layer being formed.

[0216] The foam composition may be provided to a mold to provide at least one interior surface of the mold with a quantity of the foam composition, such as a layer of the foam composition, which may be understood as a thickness of the foam composition, such as a variable thickness or a substantially constant thickness, that is typically non-planar and present on the interior surface of the mold and conforms to the shape of the surface.

[0217] Typically, the molding process involves pressing the fiber composition within the interior space of a mold by bringing parts of the mold closer together.

[0218] The process for forming a multi-layer foam structure may include supplying a first fiber composition in a foamed state to a mold and molding the first fiber composition in the mold to form a first foamed fiber layer. Thereafter, without removing the first fiber layer from the mold, the process continues by supplying a second fiber composition in a foamed state to the mold and molding the second fiber composition in the mold to form a second foamed fiber layer, resulting in a two-layer molded foam structure in the mold. The process may be continued to add additional fiber layers to the molded foam structure.

[0219] The first and second fiber compositions may differ from each other, for example, with respect to additives such as foaming agents, barrier agents, hydrophobic agents, or with respect to the cellulosic fibers.

[0220] Unless otherwise specified, "mold portion" refers to the portion of the mold that defines the interior space and contributes to the formation of the foamed fiber composition.

[0221] The second foamed fiber layer may be fed and positioned in the mold either above or below the first foamed fiber layer, and the feeding steps may be performed in either order, i.e., either the first layer or the second layer may be formed in the mold first.

[0222] For example, when making a multi-layer molded foam structure, the layers can be formed in any suitable order. An inner (prospective) fibrous layer can be formed first, followed by upper and lower fibrous layers on either side of the inner fibrous layer. Alternatively, either the upper (prospective) fibrous layer or the lower (prospective) fibrous layer can be formed first, followed by the other fibrous layers.

[0223] It may also be envisaged that the product is obtained by using separate molds for preparing the first and second foamed fiber layers, and the obtained first and second fiber layers are bonded together in a hot pressing process.

[0224] In one embodiment, feeding into the mold comprises feeding the foamed fiber composition in a foamed state into an interior space or volume of the mold, the interior space being bounded by the interior surface of the mold.

[0225] It is preferable that a vacuum can be applied during the dehydration step.

[0226] The final multi-layer foam structure is then opened and removed from the mold.

[0227] It is preferable to be able to adjust the distance between the various parts of the mold during delivery and molding of the foam composition.

[0228] Before starting to add more fiber composition to the mold, it is usually necessary to expand the interior space of the mold by moving the mold parts away from each other. The volume of the interior space may be reduced or expanded to accommodate the foam already added or to make room for the next foam to be added.

[0229] When adjusting the volume of the entire interior space of the mold, some parts of the mold may remain stationary while other parts may move.

[0230] In one example, during closure or expansion, one or more portions of the mold remain stationary while one or more other portions of the mold move.

[0231] For example, a mold may consist of two sub-molds, e.g., two halves, positioned opposite each other and movable relative to each other. The sub-molds may be moved toward each other to form the product. The sub-molds may be moved apart to enlarge the interior space, or may be moved further apart to open the mold and remove the molded product from the mold.

[0232] In one example, the product is obtained by using a mold consisting of two parts, a negative mold and a positive mold, which can be arranged facing each other to enclose an internal space, also called a molding space or molding cavity, between the two parts. The composition to be molded or shaped is fed into the molding space, and the negative mold and / or the positive mold are brought closer together to give the composition a shape corresponding to the shape of the molding space. "Approaching" refers to the process by which the internal space is reduced by moving one or both of the positive and negative molds.

[0233] Dehydration of the structure can be carried out by applying a vacuum to the interior space of the mold containing the provided foam composition.

[0234] The dewatering step precedes the hot pressing step, which bonds all the layers together to create a typically smooth, dry final product.

[0235] In hot pressing, the temperature is typically above room temperature, for example at least 50°C, such as at least 100°C, for example in the range of at least 150-240°C.

[0236] In hot pressing, a pressure lower than atmospheric pressure, for example, a pressure of 600 kPa or less, may be applied.

[0237] The hot pressing may comprise two or more successive hot pressing steps, the total duration of which may be less than 60 seconds, for example less than 30 seconds.

[0238] During hot pressing, heat is applied from one or both sides of the material being pressed, and in embodiments, heat is applied from only one side.

[0239] For example, the hot pressing may include two hot pressing steps that apply heat from the same side, or the hot pressing may include two hot pressing steps that apply heat from different sides.

[0240] Hot pressing can contribute to the development of barrier or other functional properties through chemical reactions that occur at elevated temperatures, such as crosslinking or curing reactions, and therefore can be advantageous when using additional chemicals whose effects are enhanced by crosslinking or curing.

[0241] Hot pressing may also contribute to the flow of additives such as barrier agents and hydrophobic agents within the multilayer fibrous structure.

[0242] Hot pressing may contribute to the flow of the barrier chemical, for example, hot pressing from one side may direct the flow of the barrier chemical within the layer differently compared to hot pressing symmetrically from both sides.

[0243] The hot pressing preferably involves impulse drying.

[0244] Impulse drying is a wet-compression process, usually involving the application of heat. The added heat serves two purposes: it reduces the viscous resistance of the water, and it softens the pulp structure, improving compressibility and creating a smooth surface. If the heat transfer coefficient is high enough, a vapor phase is generated on the wet side in contact with the hot medium. The expanding vapor displaces the bound water, aiding in the dewatering process.

[0245] Additives, barrier properties, sizing agents At least one of the fibrous layers may contain one or more additives such as talc, clay, pigments such as calcium carbonate, retention aids, fixatives, barrier agents, latex binders, water soluble binders, starch, wet strength agents, sizing agents such as CMC, AKD, etc.

[0246] The amount of the additive may be in the range of 0.01 to 30% by weight, for example, 0.01 to 10% by weight, for example, 0.1 to 8% by weight, for example, 1 to 5% by weight, calculated based on the weight of dry fibers in the fiber layer. The amount and nature or function of the additive in each fiber layer may be selected independently. Preferably, the overall properties of the product can be optimized by adjusting the contribution of the additive in each fiber layer.

[0247] Any of the fibrous layers of the product can have barrier properties by refining the fibers and / or adding barrier agents, hydrophobic agents, reinforcing agents, and / or selecting an appropriate foaming agent. The fibrous layers can have different barrier properties. For example, one fibrous layer can be oil and grease resistant, while another fibrous layer can be water resistant.

[0248] Examples of barrier additives include sizing agents or hydrophobic agents, typically for internal and / or surface sizing, preferably for internal sizing. The sizing agent is preferably a foaming sizing agent, such as a resin sizing agent. In embodiments, the sizing agent is configured so as not to inhibit or reduce the foaming action of the foaming chemical.

[0249] The barrier additive can be added to the fibrous raw material or slush prior to the foaming step, e.g. at a consistency of 0.5-15%, e.g. 2-10%, and / or can be added to the foam or mixed with the fibrous slush at said consistency prior to the foam formation step.

[0250] The barrier additive is preferably added to the fibrous material or slush at a consistency of less than 10%, for example less than 5%.

[0251] In an embodiment, at least one of the fibrous layers includes a sizing agent.

[0252] In some embodiments, the fiber compositions for the individual layers of a multilayer product can be dosed with different amounts of sizing agent. For example, at least prior to hot pressing, the fiber composition for a lower fiber layer of the product can contain less hydrophobic agent or sizing agent than the fiber compositions for the other layers, particularly the upper fiber layer of the product. For example, the fiber composition for the lower fiber layer can contain 50% less sizing agent by weight than the fiber composition for the upper fiber layer. Preferably, during hot pressing or impulse drying, a portion of the sizing agent dosed to the upper fiber layer migrates to the other fiber layers.

[0253] The sizing agent may be a cationic sizing agent, an anionic sizing agent, and / or a reactive sizing agent.

[0254] Suitable cationic sizing agents include cationic starch and starch derivatives, as well as the corresponding carbohydrate-based natural polymers. Synthetic polymers such as styrene / acrylate copolymers (SA), polyurethanes, and alkylated urethanes can be used.

[0255] Suitable anionic sizing agents include anionic starch and starch derivatives and the corresponding carbohydrate-based natural polymers such as carboxymethylcellulose and its salts, alkylcelluloses such as methylcellulose and ethylcellulose. Synthetic polymers include styrene / maleic acid copolymers (SMA), diisobutylene / maleic anhydride, styrene acrylate copolymers, acrylonitrile / acrylate copolymers, and polyurethanes and similar latex products containing the same chemical functional groups.

[0256] Non-ionic starches can also be used.

[0257] In some embodiments, the sizing agent is a modified rosin, a wax, an oil, or a polymer.

[0258] An advantage of using a sizing agent is that the unwanted absorption of liquid and / or water and / or moisture into the foamed molded structure may be reduced, i.e., the moisture or water resistance of the product may be improved.

[0259] An example of a wax-type sizing agent is alkyl ketene dimer (AKD).

[0260] The AKD may be a cationic AKD or an anionic AKD, preferably a cationic AKD.

[0261] The AKD may be in the form of a dispersion, such as an aqueous dispersion of the AKD and the polymer. The polymer may be a cationically modified starch.

[0262] An example of an oil is alkenyl succinic anhydride (ASA).

[0263] An example of a polymeric sizing agent is styrene acrylate emulsion (SAE).

[0264] Preferably, the sizing agent is AKD or a similar wax.

[0265] Examples of slightly cationic or non-ionic sizing agents include AKD dispersions that do not contain cationic polymers and resin adhesives such as foamable resin adhesives. The advantage of such sizing agents is that they are less likely to inhibit or reduce, and may even enhance, the foaming action of foaming chemicals.

[0266] An example of a sizing agent is a mixture of a resin adhesive and AKD.

[0267] For example, the sizing agent may be selected from the group of AKD, ASA, rosin products, polymer and copolymer products.

[0268] In some embodiments, the sizing agent is AKD stabilized or emulsified with cationic starch or other cationic polymer.

[0269] In some embodiments, the sizing agent is AKD that is not stabilized or emulsified by any cationic starch or other cationic polymer.

[0270] In some embodiments, the net negative impact of sizing agents on foam stability and quality can be mitigated by selecting the appropriate combination and location of foaming chemicals. In particular, it is advantageous to mutually optimize the charge state or charge environment of the sizing agent and foaming chemical.

[0271] For example, in the case of cationic sizing agents, it may be advantageous to use anionic surfactants and / or nonionic polymers as foaming agents.

[0272] As another example, in the case of a combination of cationic and nonionic sizing agents, it may be advantageous to use an anionic surfactant as the foaming chemical.

[0273] In some embodiments, at least one of the fibrous layers includes a sizing agent, optionally in combination with one or more other additives. Preferably, the fibrous layer also includes a PAE, which can enhance the bonding of the sizing agent, particularly AKD, to the fibers.

[0274] Typically, a hydrophobic agent, such as a sizing agent, is added to the foamed fiber composition after the foaming step.

[0275] In embodiments, the hydrophobic agent, such as a sizing agent, is added at a later stage than other additives, such as a blowing agent and, optionally, a retention aid.

[0276] In a multi-layer product, one or more layers may be free of anionic surfactants while one or more other layers may contain anionic surfactants. Optionally, the layer(s) free of anionic surfactants may also contain a sizing agent, such as a cationic sizing agent, and optionally a nonionic polymer.

[0277] For example, the fibrous surface layer of the product may comprise a non-ionic polymer.

[0278] For example, the inner layer of the product may be free of anionic surfactants, and the inner layer may include a sizing agent.

[0279] For example, the backing layer of the product may include an anionic surfactant.

[0280] In one embodiment, at least one of the fibrous layers comprises talc, for example, 0.1 to 5% by weight talc.

[0281] In one embodiment, at least one of the fibrous layers comprises clay, for example 0.1 to 5 wt % clay.

[0282] In one embodiment, at least one of the fibrous layers comprises calcium carbonate, for example, 0.1 to 5% by weight calcium carbonate.

[0283] In one embodiment, at least one of the fibrous layers comprises a barrier agent selected from polyolefins, polyesters, other thermoplastic polymers, biodegradable polymers such as polylactic acid, starch and its derivatives, plastomers, elastomers, ethylene vinyl alcohol, and derivatives, copolymers, and mixtures thereof.

[0284] In one embodiment, at least one of the fibrous layers comprises 0.1 to 15 wt %, for example 0.1 to 10 wt %, for example 0.1 to 5 wt %, of a barrier agent, such as a dispersed polymeric barrier agent. Such barrier agents typically provide barrier properties throughout the structure of the fibrous layer, especially in the absence of refinement.

[0285] In one embodiment, at least one of the fibrous layers comprises 0.1 to 5 wt % of a polymer latex binder, such as styrene butadiene latex, styrene acrylate latex, or polyvinyl acetate latex.

[0286] In one embodiment, at least one of the fibrous layers comprises 0.1 to 25 wt. %, for example 5 to 15 wt. % polyvinyl alcohol (PVA).

[0287] In one embodiment, at least one of the fibrous layers comprises 0.1 to 20% by weight, for example 0.1 to 5% by weight, of starch.

[0288] The starch may be native, modified, cooked, or swollen cationic starch.

[0289] In one embodiment, at least one of the fibrous layers comprises 0.1 to 5 wt % CMC.

[0290] In one embodiment, at least one of the fibrous layers contains 0.1 to 5 wt. % polyamide epichlorohydrin (PAE). Preferably, the fibrous layer also contains a sizing agent such as AKD. The PAE can strengthen the bond between the sizing agent and the fibers.

[0291] In one embodiment, at least one of the fibrous layers includes a retention aid, for example, in an amount of 0.1 to 5% by weight.

[0292] The retention aid may be an anionic polymeric retention aid.

[0293] In one embodiment, at least one of the fibrous layers comprises a wet strength agent.

[0294] Wet strength agents include polyamide epichlorohydrin, polyethyleneimine, dialdehyde starch, polyacrylamide, glyoxal or melamine formaldehyde, polyamidoamine epichlorohydrin, urea formaldehyde melamine, and any combination thereof.

[0295] In one embodiment, at least one of the fibrous layers comprises a dispersing or flotation agent.

[0296] In one embodiment, at least one of the fibrous layers comprises a mineral filler, such as 0.1 to 20% by weight of a mineral filler.

[0297] In an embodiment, the fibrous layer of the product comprises less than 5% by weight, such as less than 1% by weight, of mineral filler.

[0298] In one embodiment, all or at least one of the fibrous layers comprises 0.1 to 20 wt. % of a reinforcing additive such as nanocellulose or microfibrillated cellulose (MFC), or other reinforcing cellulose-based material.

[0299] Preferably, the fibrous layer of the product comprises less than 10% by weight, such as less than 5% by weight, such as less than 2% by weight, of waxes, plastics, and fluorochemicals. In one embodiment, the fibrous layer of the product comprises less than 2% by weight, such as less than 1% by weight, of plastics. In one embodiment, the fibrous layer of the product comprises less than 2% by weight, such as less than 1% by weight, of fluorochemicals. In some embodiments, the product is substantially free of waxes, plastics such as thermoplastics, and fluorochemicals, and particularly free of fluorochemicals.

[0300] For ovenable applications, additives and foaming chemicals may be selected from among those approved for use in food contact materials or packaging and in ovenable food packaging materials intended for heating. Additives should preferably be selected from those approved in BfR XXXVI / 2. Paper and Paperboard for Baking Purposes: https: / / www.bfr.bund.de / cm / 349 / XXXVI-2-Paper-and-Paperboard-for-Baking-Purposes.pdf.

[0301] For non-oven-safe products, there is greater freedom in the choice of additives and foaming chemicals from all additives approved for use in food contact materials or packaging.

[0302] The amount of barrier additive may range from 0.5 to 25% by weight, such as 1 to 10% by weight, such as 2 to 10% by weight, such as 5 to 8% by weight, calculated on the weight of dry fibers in the fibrous layer.

[0303] "Food contact material" refers to all materials and articles, such as packaging and containers, that are intended to come into contact with food.

[0304] This product should comply with Regulation (EC) No 1935 / 2004.

[0305] In one embodiment, additives such as pigments, binders, sizing agents, etc. are compatible with ovenable products.

[0306] Product and weight In some embodiments, the dry weight of the product is between 5 and 900 g / m 2 range, e.g., 100 to 900 g / m 2 range, e.g., 200 to 750 g / m 2 range, e.g., 300-600g / m 2 is.

[0307] In an embodiment, the dry weight of each of the fibrous layers is between 40 and 400 g / m 2 range, e.g., 80 to 300 g / m 2 is.

[0308] In one embodiment, the dry weight of the bottom and / or inner fibrous layers of the product is between 80 and 400 g / m 2 range, e.g., 100-400g / m 2 , for example, 200 to 300 g / m 2 is.

[0309] In one embodiment, the bottom and top fibrous layers of the product each have a dry weight of 80 to 150 g / m 2 is in the range.

[0310] In one embodiment, the dry weight of the inner or middle fibrous layer of the product is between 150 and 250 g / m 2 The range is.

[0311] In one embodiment, the dry weight of the first fibrous layer and / or the second fibrous layer of the product is between 10 and 150 g / m 2 range, e.g., 60 to 150 g / m 2 , or for example 20 to 60 g / m 2 , for example 30 to 50 g / m 2 is.

[0312] In an embodiment, the average density of the product is 500 kg / m 3 Larger, e.g. 600 kg / m 3 Larger, e.g. 700 kg / m 3 Greater than.

[0313] In an embodiment, the density of the inner fibrous layer or layers is 100 kg / m 3 Greater than.

[0314] In some embodiments, the product may include at least three fiber layers, such as exactly three fiber layers, or between 2 and 20 fiber layers.

[0315] In some embodiments, the product includes exactly two fiber layers or exactly three fiber layers.

[0316] Preferably, the product is a three-dimensionally molded multi-layer textile product obtained using a mold comprising at least one three-dimensional non-planar mold surface, the product exhibiting a three-dimensional shape that conforms to the shape of the three-dimensional non-planar mold surface.

[0317] For example, the product can have the shape of a cup, a plate, a bowl, a frying pan, a clamshell, or a tray.

[0318] Typically the product is a food or liquid package or container, or product for serving food or liquid, such as a drinking cup, a food tray or plate, a baking pan, a disposable lasagna tray type product, etc.

[0319] In some embodiments, the product is ovenable, for example, can be baked in an oven at a temperature of at least 100°C, preferably at least 220°C.

[0320] In some embodiments, the product is a package or container of a microwaveable food or liquid, such as a food tray.

[0321] In one example, the product is a baking vessel such as an ovenable pan.

[0322] The product can be used to package, store, serve, prepare, cook, and / or heat food or liquids. The liquids are drinkable liquids, such as beverages.

[0323] More generally, the product may be used to package or store any product that contains oil and / or water.

[0324] The product may be intended to be used or installed on oily, greasy or wet surfaces or in a damp environment.

[0325] The thickness, i.e., the smallest dimension, of the product will be in the range of 300 to 1000 μm, for example 450 to 900 μm.

[0326] The Bendtsen smoothness of the product will be in the range of 50-4000 ml / min, for example 100-1000 ml / min.

[0327] The tensile index of the product will be in the range of 10-60, such as 20-60 Nm / g in the machine and cross directions.

[0328] The product's modulus of elasticity will be in the range of 3.0 to 6.0 GPA in both the machine and cross directions.

[0329] The bending stiffness (Taber 15°) of the product ranges from 20 to 80 mNm, for example from 20 to 50 mNm, or from 40 to 80 mNm in the machine direction and cross direction.

[0330] In a first example, the following blowing agents and additives are used in the manufacture of a three-ply textile product: Upper fiber layer: SDS, PAE, AKD Middle fiber layer: PVA Lower fibrous layer: SDS, AKD In a second example, the following blowing agents and additives are used in the manufacture of a three-ply textile product: Upper fiber layer: PVA, AKD Middle fiber layer: SDS, PAE, AKD Lower fiber layer: PVA, AKD In a third example, the following blowing agents and additives are used in the manufacture of a three-ply textile product: Upper fiber layer: SDS, PAE, AKD Middle fiber layer: SDS Lower fiber layer: PVA

[0331] Reference is now made to the drawings. 1 shows a schematic diagram of a multilayer fibrous product in accordance with at least some embodiments of the present invention. The product includes a first fibrous layer 101, which is a bottom fibrous layer, a second fibrous layer 102, which is a top fibrous layer, and an inner fibrous layer 103 between the first fibrous layer 101 and the second fibrous layer 102.

[0332] Figure 2 (reference) shows stereomicroscope images of a three-layer structure obtained by foam molding using SDS as a foaming agent. Scale: 1000 μm (left), 1000 μm (center), 100 μm (right).

[0333] Figure 3 shows stereomicroscope images of a three-layer structure obtained by foam molding using PVA as a blowing agent, AKD as a hydrophobic agent, and a retention aid. Scales: 1000 μm (left), 1000 μm (center), and 100 μm (right).

[0334] Figure 4 shows stereomicroscope images of a monolayer structure obtained by foam molding using PVA as a foaming agent, AKD as a hydrophobic agent, and a retention aid. Scales: 1000 μm (left), 1000 μm (center), and 100 μm (right).

[0335] 5 is a flow chart showing process steps for producing a multi-layer foam molded article according to an embodiment of the present invention. The method includes the following steps:

[0336] 501: Prepare a fiber stock with a fiber consistency of, for example, 1-3%.

[0337] 502: The stock is treated, for example, by purification, pH adjustment, and / or addition of chemicals such as PAE, retention aids, MFC, pigments, and mixtures thereof.

[0338] 503a, 503b, 503c: From the processed stock, prepare foams 504a, 504b, 504c (not shown), respectively.

[0339] 505: The foams 504a, 504b, 504c are molded to obtain a multi-layer foam molded structure.

[0340] 506: The multi-layer foam molded structure is hot pressed from one side or both sides.

[0341] 507: Perform finishing such as coating, printing, cutting, and / or packaging as required.

[0342] Figure 6 illustrates foam molding of a three-layer fibrous structure in accordance with at least some embodiments of the present invention. Pressure can be applied from only one side of the fibrous structure or layer. Vacuum can be applied from the other side of the fibrous structure or layer. On the left side of Figure 6, a fibrous layer is formed that will eventually become the middle fibrous layer. In the center of Figure 6, an additional fibrous layer is formed that will eventually become the upper fibrous layer. On the right side of Figure 6, an additional fibrous layer is formed that will eventually become the lower fibrous layer, resulting in a three-layer fibrous structure. [Example]

[0343] The following three-ply samples 1-4 were prepared and tested. In all samples, the upper and lower fiber layers contained 50% BHKP (bleached hardwood kraft pulp) and 50% BSKP (bleached softwood kraft pulp), and the middle layer contained 100% BCTMP (bleached chemi-thermomechanical pulp).

[0344] Sample 1 is a reference sample. SDS was used as the foaming agent. No retention aids, PAE, or AKD were used.

[0345] In sample 2, SDS was used as the blowing agent, and PAE and AKD were applied as additives.

[0346] In sample 3, PVA was used as the blowing agent. Retention aid and AKD were used as additives.

[0347] In Sample 4, SDS and PVA were used as the foaming agents. Retention aid and AKD were used as additives.

[0348] In these tests, SDS was applied as a surface active foaming agent (as an anionic surfactant), PVA as a polymeric foaming agent (as a nonionic polymer), AKD as a hydrophobic agent (as an internal sizing agent), PAE as a wet strength enhancer, and retention aid.

[0349] The values ​​for each layer are indicated by the notation upper / middle / lower in Table 1. The contact angle values ​​indicate the surface free energy (Kruss) contact angle at 1 second (1 s).

[0350] [Table 1]

[0351] Based on the experiments, the following was observed: Hydrophobicity increased significantly for AKD, as indicated by an increase in contact angle and a decrease in Cobb value. The decrease in polar content also supports the conclusion that wettability decreased when the overall surface energy of the sample was reduced. By adding carefully selected surfactants, hydrophobic agents, and additives to the individual layers of a fibrous multilayer product, the surface and functionality of the product can be modified to suit final processing steps such as coatings or end uses such as food packaging.

[0352] It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein, but extend to equivalents thereof recognized by those of ordinary skill in the relevant art. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0353] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.

[0354] For convenience, multiple items, structural elements, components, and / or materials may be presented herein in common lists. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Accordingly, individual members of such lists should not be construed as de facto equivalents of other members of the same list merely by virtue of being presented in a common group, unless indicated to the contrary. Furthermore, various embodiments and examples of the present invention may be referenced herein, along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives should not be construed as de facto equivalents of one another, but should be considered as separate and independent manifestations of the present invention.

[0355] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are set forth, such as example lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. However, one skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0356] While the foregoing examples illustrate the principles of the present invention in one or more particular applications, it will be apparent to those skilled in the art that numerous changes in the embodiments, uses and details may be made without the exercise of inventive faculty and without departing from the principles and concepts of the present invention. Accordingly, the present invention is not limited except as by the claims set forth below.

[0357] The verbs "comprise" and "comprise" are used in this document as open limitations that do not exclude or require the presence of unrecited features. Features recited in dependent claims may be freely combined with one another, unless expressly stated otherwise. Furthermore, it is to be understood that the use throughout this document of "a" or "an", i.e., the singular, does not exclude the plural. [Industrial Applicability]

[0358] The present invention is industrially applicable at least in the production of molded textile products.

[0359] acronym SDS: sodium dodecyl sulfate PVA: Polyvinyl alcohol AKD: alkyl ketene dimer PAE: Polyamide epichlorohydrin MFC: Microfibrillated cellulose APG: alkyl polyglycoside BHKP: bleached hardwood kraft pulp BSKP: bleached softwood kraft pulp BCTMP: Bleached Chemi-Thermomechanical Pulp [Explanation of symbols]

[0360] 101: First fiber layer 102: Second fiber layer 103: inner fiber layer 501: Adjust the fiber stock to a fiber consistency of, for example, 1-3% 502: The stock is treated, for example, by purifying, adjusting pH, and / or adding chemicals such as PAE, retention aids, MFC, pigments, and mixtures thereof. 503a, 503b, 503c: Prepare foams 504a, 504b, 504c (not shown), respectively, from the processed stock. 505: Forming the foams 504a, 504b, 504c to obtain a multi-layer foamed structure. 506: Multilayer foam molded structure is hot pressed from one side or both sides 507: Finishing, such as coating, printing, cutting, and / or packaging, as required.

Claims

1. forming a multi-layer foamed fibrous structure from foamed fibrous compositions in a mold, each of said foamed fibrous compositions comprising cellulose fibers, water, air, and at least one blowing agent; dehydrating the foamed fibrous structure; and hot pressing the dehydrated structure to obtain a shaped textile product; 1. A method comprising: the at least one blowing agent comprises at least one surfactant blowing agent and / or at least one polymeric blowing agent; The method wherein at least one of the foamed fiber compositions comprises a hydrophobic agent.

2. Each layer is formed from a respective foamed fiber composition; The method of claim 1.

3. each foamed fiber composition independently comprises at least one surface-active foaming agent, e.g., an anionic surfactant, and / or at least one polymeric foaming agent, e.g., a nonionic polymer; The method according to claim 1 or 2.

4. In the method, at least two different blowing agents are used, such as at least three different blowing agents, for example at least four different blowing agents. The method according to any one of claims 1 to 3.

5. at least one of the foamed fiber compositions includes both a surfactant foaming agent and a polymeric foaming agent; The method according to any one of claims 1 to 4.

6. At least two of the foamed fiber compositions comprise different foaming agents, e.g., different sets of foaming agents; The method according to any one of claims 1 to 5.

7. the total amount of blowing agent in each foamed fiber composition is in the range of 0.1 to 35 wt. %, such as 5 to 20 wt. %, such as 1 to 3 wt. %, or such as 0.1 to 1 wt. %, calculated from the weight of dry fiber in said foamed fiber composition; The method according to any one of claims 1 to 6.

8. the foamed fiber composition for at least one fiber layer comprises at least 0.5 wt. %, such as at least 1 wt. %, such as at least 5 wt. %, such as 5-35 wt. %, of a non-ionic polymer as a foaming agent, calculated on the weight of dry fibers in the fiber composition; the foamed fiber composition for at least one fiber layer, whether the fiber layer is the same or a different fiber layer, comprises at least 0.1 wt. %, such as at least 0.5 wt. %, such as at least 1 wt. %, such as 0.1-1 wt. % or 1-5 wt. %, of an anionic surfactant as a foaming agent, calculated on the weight of dry fiber in the fiber composition; The method according to any one of claims 1 to 7.

9. the at least one non-ionic polymer is selected from the following group: polyvinyl alcohol (PVA), polyethylene glycol dodecyl ether (Brij), polyethylene glycol sorbitan monolaurate (Tween 20), PEG-6 lauramide, alkyl polyglucosides (APG), fatty alcohol ethoxylates, alkylphenol ethoxylates, fatty acid ethoxylates, fatty amide ethoxylates, alkyl glucosides, sugar-based non-ionic polymers such as sorbitan alkanoates, sorbitan fatty acid esters (Span), and combinations thereof; The method according to any one of claims 1 to 8.

10. the at least one anionic surfactant is selected from the following group: sodium dodecyl sulfate, α-olefin sulfonate, alkyl sulfate, alkyl benzene sulfonate, alkyl ether sulfate, taurate, isethionate, and combinations thereof; The method according to any one of claims 1 to 9.

11. the foamed fiber composition for at least one fiber layer of the product comprises at least 0.5% by weight, such as at least 1% by weight, such as 1 to 50% by weight, of polyvinyl alcohol, calculated on the weight of dry fiber in the fiber composition; The method according to any one of claims 1 to 10.

12. the foamed fiber composition for at least one fiber layer comprises a nonionic polymer and an anionic surfactant in a molar ratio of 5:95 to 50:50, for example, 10:90 to 30:70; The method according to any one of claims 1 to 11.

13. At least two, e.g., at least three, of the foamed fiber compositions further comprise a hydrophobic agent or a sizing agent; The method according to any one of claims 1 to 12.

14. The hydrophobic agent is contained in at least the last formed fiber layer. The method according to any one of claims 1 to 13.

15. The hydrophobic agent is contained in at least the upper fiber layer. The method according to any one of claims 1 to 14.

16. The hydrophobic agent is contained in at least the inner fiber layer. The method according to any one of claims 1 to 15.

17. all inner fibrous layers, e.g. all fibrous layers of the product, contain a hydrophobic agent, thereby imparting barrier properties, such as water resistance, to the product; The method according to any one of claims 1 to 16.

18. The hydrophobic agent is an alkyl ketene dimer (AKD). The method according to any one of claims 1 to 17.

19. the foamed fiber composition for at least one fiber layer comprises at least 0.1 wt. %, for example 0.1 to 1 wt. %, for example 0.2 to 0.8 wt. %, of a hydrophobic agent, preferably AKD, calculated on the weight of dry fibers in the fiber composition; The method according to any one of claims 1 to 18.

20. the shaped textile product comprises at least three fiber layers, for example exactly three fiber layers; The method according to any one of claims 1 to 19.

21. the foamed fiber composition for at least one fiber layer comprises a surfactant foaming agent, a hydrophobic agent and a wet strength agent, preferably SDS, AKD and PAE, respectively; The method according to any one of claims 1 to 20.

22. the resulting shaped textile is further coated, or configured to be coated, with a non-fibrous barrier coating layer that provides resistance to water, water vapor, gases, e.g., oxygen, and / or oil and grease; The method according to any one of claims 1 to 21.

23. The cellulose fibers consist of or comprise bleached chemical pulp and / or bleached chemi-thermomechanical pulp, The method according to any one of claims 1 to 22.

24. the foamed fiber composition for at least one fiber layer comprises 0.1 to 1 wt. %, for example 0.2 to 0.8 wt. %, of AKD, calculated on the weight of dry fibers in the fiber composition; The method according to any one of claims 1 to 23.

25. the molded textile product comprises at least three fibrous layers, and the foamed textile composition for at least one fibrous layer comprises SDS as a surfactant foaming agent, AKD as a hydrophobic agent, and PAE as a wet strength agent; The method according to any one of claims 1 to 24.

26. the molded textile product comprises at least three fibrous layers; the foamed fiber compositions for the upper and lower fibrous layers include a non-ionic polymer as a foaming agent; the foamed fiber composition for the inner fiber layer comprises an anionic surfactant as a foaming agent; the foamed fiber composition for the upper fibrous layer further comprises a hydrophobic agent such as a sizing agent, and / or the foamed fiber composition for the lower fibrous layer further comprises a hydrophobic agent such as a sizing agent; The method of claim 1.

27. the molded textile product comprises at least three fibrous layers; the foamed fiber compositions for the upper and lower fibrous layers include an anionic surfactant as a foaming agent; the foamed fiber composition for the inner fiber layer comprises a non-ionic polymer as a foaming agent; the foamed fiber composition for the inner fiber layer further comprises a hydrophobic agent, such as a sizing agent; The method of claim 1.

28. the foamed fiber composition for at least one fiber layer comprises a nonionic surfactant, such as a glucamide, optionally in combination with an anionic surfactant, such as SDS; The method according to any one of claims 1 to 27.

29. A shaped multi-layer textile product obtained by the method according to any one of claims 1 to 28.

30. The dry weight of each fiber layer is 30 to 700 g / m ２ is in the range of 30. The molded multi-layer textile product of claim 29.

31. the cellulose fibers in one or more inner fibrous layers of the product have a Shopper-Riegler number of less than 50, e.g., less than 30; 31. The molded multi-layer textile product of claim 29 or 30.

32. the cellulose fibers in the lower fibrous layer of the product have a Shopper-Riegler number of at least 20, e.g., 20 to 40; A molded multi-layer textile product according to any one of claims 29 to 31.

33. the cellulose fibers in the upper fibrous layer of the product have a Schopper-Riegler number of at least 40, e.g., at least 50; A molded multi-layer textile product according to any one of claims 29 to 32.

34. 1. A packaging for food or liquid, or a product or part thereof for providing food or liquid, wherein preferably at least the upper fibrous layer adapted to come into contact with said food or liquid comprises a hydrophobic agent to impart barrier properties. A molded multi-layer textile product according to any one of claims 29 to 33.

35. Thin-walled molded textile products obtained by foam molding, the thickness of said products being variable or substantially constant, typically less than 2 mm in its shortest dimension; A molded multi-layer textile product according to any one of claims 29 to 34.

36. The product has a Bendtsen smoothness in the range of 50 to 4000 ml / min, for example 100 to 1000 ml / min, and a bending stiffness (Taber 15°) in the machine direction and cross direction in the range of 40 to 80 mNm. A molded multi-layer textile product according to any one of claims 29 to 35.

37. the cellulose fibers in one or more inner fibrous layers of the article have a Shopper-Riegler number of less than 30; the cellulose fibers in the lower fibrous layer of the article have a Schopper-Riegler number of 20 to 40; the cellulose fibers in the upper fibrous layer of the article have a Schopper-Riegler number of at least 40; A molded multi-layer textile product according to any one of claims 29 to 36.

38. 38. Use of a product according to any one of claims 29 to 37 as or part of a food or liquid packaging, food or liquid serving product or in packaging, serving, storing, preparing, cooking and / or heating food or liquid.

39. 1. Use of a nonionic polymer as a foaming agent and AKD as an internal sizing agent in the manufacture of a textile product or part thereof, such as a layer thereof, which is formed by a process comprising foam molding followed by hot pressing.

Images