Oven-safe molded multi-layer textile product and its uses

Abstract

According to one aspect of the invention there is provided an ovenable molded multi-layer fibrous product comprising a first fibrous layer comprising a cellulosic fibrous material and a second fibrous layer on top of the first fibrous layer, the second fibrous layer comprising a cellulosic fibrous material, and the first and / or second fibrous layer exhibit barrier properties throughout substantially their structure, said product being configured to heat food or liquid thereon.

Description

[Technical field]

[0001] FIELD OF THEINVENTION This invention relates to molded textile products, and more particularly to multi-layer molded textile products. [Background technology]

[0002] In a known technique for producing molded textile products, the foam is deposited in a trough-shaped mold with a head box. Because the forming and pressing sequences are separate, the forming and dewatering processes are slow and the foam may spread unevenly in the mold. This method is mainly suitable for products such as filters or insulators. Usually, the resulting structures, such as egg trays, are porous and have an inhomogeneous and rough surface.

[0003] Another known alternative is to prepare molded textile products using water-molding processes, but these processes are only suitable for molding a single substantially thin layer at a time, making the process cumbersome when more complex structures are desired.

[0004] It is also known to apply various barrier coating films to packaging and containers made of two-dimensional fibrous materials, such as paperboard. Such barrier coatings typically involve the use of plastic materials and films. The addition of the barrier coating may be carried out in a separate process after the manufacture of the actual fibrous substrate.

[0005] Separate barrier coating films suffer from a number of disadvantages related to adhesion of the coating film to the rest of the product and degradation of the mechanical properties of the coating film during the drying steps in manufacturing or during humidity changes during transport and storage.

[0006] In particular, ovenable food containers and packaging are currently made of paper or paperboard materials that include a plastic or wax-based barrier coating on the food contact side of the container, such as a laminated or extruded barrier coating made of polyethylene terephthalate or polyethylene.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to overcome at least some of the problems present in the known art. Summary of the Invention

[0008] The invention is defined by the features of the independent claims. Some particular embodiments are defined in the dependent claims.

[0009] According to a first aspect of the present invention there is provided a moulded multi-layer fibrous product comprising a first fibrous layer comprising a cellulosic fibrous material and a second fibrous layer on top of the first fibrous layer, the second fibrous layer comprising a cellulosic fibrous material, and the first and / or second fibrous layer preferably exhibiting barrier properties throughout their structure.

[0010] Various embodiments of the first aspect may include at least one feature from the following bulleted list. The first fibrous layer forms the bottom fibrous layer of the product in use. The second fibrous layer forms the top fibrous layer of the product when in use. The second fibrous layer is configured for direct contact with the food or liquid. The barrier properties include one or more of the following: oil and grease resistance, water resistance, water vapor resistance, fragrance resistance, gas resistance, and oxygen resistance. The first and / or second fibrous layers are oil and grease resistant substantially throughout their structure. The first and / or second fibrous layers are water resistant throughout substantially their entire structure. The first and / or second fibrous layers are water vapor resistant throughout substantially their entire structure. The cellulose fiber material includes one or more of chemical wood pulp, mechanical wood pulp, fibrillated cellulose such as microfibrillated cellulose, nanocellulose, and any other cellulose material that contains cellulose fibers or parts of cellulose fibers. Cellulosic fiber materials include bleached or unbleached chemical pulps, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp. Cellulosic fiber materials include bleached and unbleached chemi-thermomechanical pulp. The first and / or second fibrous layers of the cellulosic fibrous material comprise bleached or unbleached softwood chemical pulp and bleached or unbleached hardwood chemical pulp, such as 80-95 wt.% bleached or unbleached softwood chemical pulp and 5-20 wt.% bleached or unbleached hardwood chemical pulp. The article further includes one or more inner fibrous layers between the first fibrous layer and the second fibrous layer. Each inner fibrous layer comprises a cellulosic fibrous material, preferably a mechanical pulp, such as bleached chemi-thermomechanical (BCTMP). The top and / or bottom fiber layer comprises bleached chemical pulp. One or more of the fibrous inner layers, when present, comprises mechanical pulp and, optionally, chemical pulp. · The top fibrous layer comprises refined softwood and / or hardwood chemical pulp. The bottom fibrous layer comprises refined softwood and / or hardwood chemical pulp, preferably hardwood chemical pulp, typically refined hardwood chemical pulp. The second fiber layer forms the top fiber layer of the product. The second fibrous layer has a higher resistance to oils and greases and / or water and / or water vapour than the fibrous layer below it. The first fibre layer forms the bottom fibre layer of the product. The first fibrous layer has a higher water resistance and / or a higher water vapor resistance than the fibrous layer above it. The cellulose fibrous material of the first and / or second fibrous layer comprises cellulose fibers refined to a Shopper-Riegler number of more than 40, such as more than 70, such as more than 80. The Shopper-Riegler Count of the bottom textile layer and / or one or more inner textile layers of the product is less than 50, such as less than 30, such as less than 40. The density of the second fibrous layer is greater than the density of the underlying fibrous layer, and preferably the density of the second fibrous layer is 600 to 950 kg / m, calculated as dry solid weight per volume. 3 , 800kg / m 3 Ultra-high, 300~1000kg / m 3 is in the range. The density of one or more inner textile layers of the product is 500 kg / m 3 Less than 600kg / m 3 is less than. At least one of the fibrous layers, preferably at least the first and / or second fibrous layers, comprises one or more of the following additives: pigments, colorants and fillers such as talc, clay or kaolin, ground calcium carbonate, precipitated calcium carbonate, and titanium dioxide; barrier agents such as dispersion barrier agents; water soluble binders such as latex binders, PVA, starch, CMC; sizing agents such as AKD. At least one of the fibrous layers, preferably at least the first and / or second fibrous layer, comprises PVA. At least one of the fibrous layers, preferably at least the first and / or second fibrous layer, comprises AKD, ASA, or a resin adhesive, preferably AKD. At least one of the first and / or second fibrous layers comprises a barrier agent, such as 1 wt%, preferably at least 0.5 wt%, that provides said barrier properties throughout the structure of the fibrous layer. Product weight is 5~900g / m 2 range, e.g. 100~800g / m 2 range, e.g. 200~600g / m 2 The dry basis weight ranges from 1.0 to 1.0. The top and / or bottom fiber layers of the product are 50-200 g / m 2 , for example 80~150g / m 2 The dry basis weight ranges from 1.0 to 1.0. The top and / or bottom fiber layers of the product are 20-80g / m 2 , for example 30-50g / m 2 The dry basis weight ranges from 1.0 to 1.0. Each of the fibrous layers of the product is obtained either by foam moulding in a mould or by water moulding, preferably by foam moulding. At least one, for example at least two, preferably at least three, fiber layers of the product are obtained by foam moulding. The fibre layer, which at least exhibits barrier properties, is obtained by foam moulding in a mould. The product is a three-dimensional molded multilayer textile product obtained by using a mold comprising at least one three-dimensional non-planar mold surface, said product exhibiting a three-dimensional shape that conforms to the shape of said three-dimensional non-planar mold surface. The product is a food or liquid package or a food or liquid presentation product, such as a liquid cup or food tray.

[0011] According to a second aspect of the present invention there is provided the use of a shaped multi-layer fibrous product according to the first aspect as, or as part of, a food or liquid package or food or liquid serving product.

[0012] According to a third aspect of the invention there is provided the use of a shaped multi-layer textile product according to the first aspect in packaging, storing, serving, cooking and / or heating food or liquids.

[0013] According to a fourth aspect of the present invention, there is provided a molded multilayer textile product obtained by a process comprising the steps of forming a molded single or multi-layer foamed textile structure from at least one foamed textile composition comprising cellulose fibers, water, air and a blowing agent, dewatering the structure, preferably by applying a vacuum, and hot pressing the dewatered structure, optionally together with further fibrous layers, to obtain a molded multilayer textile product, wherein at least one of the fibrous layers of the multilayer textile product exhibits barrier properties substantially throughout its structure.

[0014] Various embodiments of the fourth aspect may include at least one feature from the following bulleted list. At least one of the foamed fiber compositions includes a barrier agent to provide said barrier properties. The step of forming a molded single or multi-layered foamed fibrous structure comprises the steps of: providing a first fiber composition; providing a second fiber composition, optionally including purifying the cellulosic fibers of the second fiber composition to a Shopper-Riegler number of preferably more than 40, such as more than 70; providing the first fiber composition in a foamed form to a mold and molding the first fiber composition in the mold to prepare a first foamed fibrous layer; and providing the second fiber composition in a foamed form to the mold and molding the second fiber composition in the mold to prepare a second foamed fibrous layer to obtain a two-layered molded foamed fibrous structure, the first foamed fibrous layer being located either above or below the second foamed fibrous layer in the mold, and the providing steps may be performed in any order. Said providing to the mould comprises providing the fibre composition in a foamed form to an interior space / volume of the mould, said interior space being bounded by the interior surface of the mould. Feeding into the mold includes feeding the fiber composition in a foamed form into a closed cavity of the mold. The molding includes pressing the fiber composition in the interior space of a mold by bringing parts of the mold closer together.

[0015] According to a fifth aspect of the present invention there is provided an ovenable moulded multi-layer textile product comprising a first fibrous layer comprising cellulosic fibrous material and a second fibrous layer on top of the first fibrous layer, the second fibrous layer comprising cellulosic fibrous material, wherein the first and / or second fibrous layer exhibit barrier properties substantially throughout their structure, the product being configured to heat food or liquid thereon, preferably to at least 100°C, preferably to at least 220°C.

[0016] Various embodiments of the fifth aspect may include at least one feature from the following bulleted list. The product further includes a non-fibrous release layer on top of the second fibrous layer that forms a top layer of the product in use, the non-fibrous release layer in direct contact with a food or liquid, the non-fibrous release layer configured to facilitate release of the food or liquid from the product after it has been in direct contact with and heated thereon. The non-fibrous release layer comprises a silicone composition. The dry basis weight of the non-fiber peeling layer is 2.0 g / m 2 Less than 0.5 to 2.5 g / m 2 It is. The first fibrous layer forms the bottom fibrous layer of the product when in use and the second fibrous layer forms the top fibrous layer of the product when in use. Barrier properties include one or more of the following: oil and grease resistance, water resistance, water vapor resistance, fragrance resistance, gas resistance, and oxygen resistance. The first and / or second fibrous layers are oil and grease resistant throughout substantially their entire structure. The first and / or second fibrous layers are water and / or water vapor resistant throughout substantially their entire structure. The article further comprises one or more inner fibrous layers between the first fibrous layer and the second fibrous layer, each comprising a cellulosic fibrous material. The second fibrous layer forms the top fibrous layer of the product and has higher resistance to oils and greases than the fibrous layers below it. The first fibrous layer forms the bottom fibrous layer of the product and has a higher water resistance and / or a higher water vapour resistance than the fibrous layers above it. The cellulose fiber material of the fiber layer of the product comprises or consists of bleached chemical wood pulp, preferably bleached softwood chemical wood pulp and / or bleached hardwood chemical wood pulp. The cellulose fibrous material of the first and / or second fibrous layer comprises cellulose fibres, preferably softwood chemical wood pulp, refined to a Shopper-Riegler number of more than 40, such as more than 70, such as more than 80. The Shopper-Riegler Count of the bottom textile layer and / or one or more inner textile layers of the product is less than 50, such as less than 30, such as less than 40. The density of the second fibrous layer is greater than the density of the underlying fibrous layer, and preferably the density of the second fibrous layer is 600 to 950 kg / m, calculated as dry solid weight per volume. 3 , 800kg / m 3 Ultra-high, 300~1000kg / m 3 is in the range. The density of the bottom textile layer and / or one or more inner textile layers of the product is 500 kg / m 3 Less than 600kg / m 3 is less than. At least one of the fibrous layers, preferably at least the second fibrous layer, comprises one or more of the following additives: pigments, barrier agents, binders, sizing agents such as AKD. At least one of the fibrous layers, preferably at least the second fibrous layer, comprises MFC and starch. -Products are, for example, 100-900g / m 2 Range: 300~600g / m 2 In the range of 200~400g / m 2 In the range of 5 to 900 g / m 2 The dry basis weight ranges from 1.0 to 1.0. The top and / or bottom fiber layers of the product are 30-50g / m 2 In the range of 20 to 80 g / m 2 The dry basis weight is The top and / or bottom textile layer of the product must be between 50 and 150 g / m 2 The dry basis weight ranges from 1.0 to 1.0. The product is a three-dimensional molded multilayer textile product obtained by using a mold comprising at least one three-dimensional non-planar mold surface, said product exhibiting a three-dimensional shape that conforms to the shape of said three-dimensional non-planar mold surface, wherein the product is preferably obtained by foam moulding or water moulding in the mold. The product is an ovenable or micro-ovenable food or liquid package, container, or tray, or a baking or cooking container such as an ovenable pan.

[0017] According to a sixth aspect of the present invention there is provided the use of an ovenable moulded multi-layer textile product according to the fifth aspect in baking, cooking and / or heating food or liquids.

[0018] According to a seventh aspect of the present invention, there is provided a molded multi-layered textile product obtained by a method comprising forming a molded multi-layered foamed textile structure from at least one foamed textile composition comprising cellulose fibers, water, air and a blowing agent, dewatering the structure, preferably by applying a vacuum, and hot pressing the dewatered structure to obtain a molded multi-layered textile product, wherein at least one of the fiber layers of the foamed molded multi-layered textile product exhibits barrier properties substantially throughout its structure.

[0019] Various embodiments of the seventh aspect may include at least one feature from the following bulleted list. The step of forming a molded multi-layer foamed fibrous structure includes the steps of: providing a first fiber composition; providing a second fiber composition, the second fiber composition comprising refining the cellulosic fibers of the second fiber composition to a Shopper-Riegler number of preferably more than 40, such as more than 70; providing the first fiber composition in a foamed form to a mold and molding the first fiber composition in the mold to prepare a first foamed fibrous layer; and providing the second fiber composition in a foamed form to the mold and molding the second fiber composition in the mold to prepare a second foamed fibrous layer to obtain a two-layer molded foamed fibrous structure. The first foamed fiber layer is located either above or below the second foamed fiber layer in the mold, and the feeding steps can be performed in either order. The hot pressing comprises two or more successive hot pressing steps. The total duration of the hot pressing is less than 30 seconds, such as less than 20 seconds.

[0020] (Advantages of the present invention)

[0021] The present invention may avoid the need for a separate non-textile barrier coating layer. Problems with adhesion of the coating may be avoided.

[0022] The present invention may allow for rapid production of multi-layer molded textile products. Cycle times may be short. Wetting or rewetting of the product by a separate coating step may be avoided.

[0023] The present invention may allow the properties of the individual layers to be easily tailored.

[0024] The present invention may enable the production of lightweight, bulky and homogeneous multi-layer fiber mouldings. Due to the light weight of the product, logistics and transport costs may be reduced.

[0025] The present invention may avoid separate conversion steps and conversion logistics.

[0026] In this product, the distribution of cellulose fibers can be more uniform.

[0027] In the present invention, fiber clumping and hazy appearance can be avoided or reduced.

[0028] The present invention may avoid the use of a separate plastic barrier coating.

[0029] The present invention can provide ovenable and / or micro-ovenable, biodegradable, compostable and recyclable multi-layer molded fiber products.

[0030] The present invention may reduce energy consumption due to a reduced need for dewatering and drying of the product, especially when foam molding is used.

[0031] The present invention may reduce production costs associated with cycle times, dewatering, drying, and chemicals. Chemical retention may be improved, especially when foam molding is used.

[0032] The present invention can provide textile products with good barrier properties.

[0033] The present invention can provide textile products of complex shapes that are free of wrinkles and cracks.

[0034] The present invention can provide plastic-free textile packaging that is recyclable in existing textile recycling infrastructure.

[0035] The present invention may make it possible to replace existing, often plastic-based, packaging solutions. [Brief description of the drawings]

[0036] [Figure 1] 1 is a schematic diagram illustrating a multi-layer fibrous product according to at least some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Unless otherwise stated herein or apparent from the context, percentages referred to herein are expressed as weight percentages based on the total dry weight of the respective composition or layer.

[0038] In this context, "resistance", such as water resistance, means that the material or layer resists penetration of the substance in question. In a preferred embodiment, the material or layer exhibits "repellency", such as water repellency, meaning that the substance in question cannot easily penetrate the material or layer. In a more preferred embodiment, the material or layer exhibits "proof", such as waterproofness, meaning that the substance in question cannot penetrate the material or layer during normal use of a product that includes the material or layer. That is, resistance to penetration of the target substance increases in the following order: "resistance" < "repellency" < "proofness".

[0039] Also, in this context, reference to "resistant" means "at least resistant", i.e. the material or layer may exhibit water repellency or even waterproofing.

[0040] In the present context, the expression "a layer exhibits barrier properties" generally means that the layer is configured, e.g. modified or tailored, to have increased resistance to the penetration and / or migration of a particular (predetermined) substance or group of substances. Such a layer exhibiting barrier properties is thus configured to form a barrier to the penetration and / or migration of said predetermined substances.

[0041] As used herein, the phrase "a layer exhibits barrier properties throughout substantially its entire structure" means that the barrier properties are not limited to only a small portion (e.g., less than 50%) of the volume of the layer, such as a thin surface portion of the layer.

[0042] As used herein, the term "hot pressing" generally refers to a process of increasing pressure and temperature for a period of time. Hot pressing may include several successive cycles or steps of increasing pressure and temperature. In some cases, hot pressing may also include the application of subatmospheric pressure.

[0043] In this specification, the term "molded product" refers to a product obtained by molding or giving shape to a product in a closed or closable cavity of a mold. "Molding" does not usually refer to simply pressing a product between two plates.

[0044] As used herein, the term "ovenable product" refers to a product that is configured to be heated in an oven, typically while holding or carrying food or liquid for human or animal consumption.

[0045] In the present context, the term "food" generally refers to food for human or animal consumption.

[0046] As used herein, the term "liquid" generally refers to liquid or flowable materials for human or animal consumption, such as beverages.

[0047] The present invention provides new molded textile products with improved barrier properties. At least a portion of the product may be manufactured by a foam-based process. Foam molding advantageously allows for the preparation of molded multi-layer structures and the tailoring of the properties of the individual layers.

[0048] The products are typically three-dimensional molded multi-layer products obtained using a foam molding process.

[0049] Preferably, at least one of the fibrous layers prepared by foam molding exhibits improved barrier properties, such that at least one of the fibrous layers can act as a barrier against oils, grease, fats, water, water vapor, liquids, fragrances, gases and / or oxygen.

[0050] According to the invention, the product is a molded multi-layer fibrous product comprising a first fibrous layer comprising a cellulosic fibrous material and a second fibrous layer on top of the first fibrous layer, the second fibrous layer comprising a cellulosic fibrous material, the first and / or second fibrous layer exhibiting barrier properties substantially throughout their structure. In a preferred embodiment, the product is configured to heat food or liquid thereon to at least 100°C, preferably at least 220°C.

[0051] The cellulosic fibrous material may include wood pulp selected from the group of chemical pulp, mechanical pulp, and any combination thereof.

[0052] The cellulose fibrous material may include one or more of chemical wood pulp, mechanical wood pulp such as chemithermomechanical pulp, fibrillated cellulose such as microfibrillated cellulose, nanocellulose, and any other cellulose material that includes cellulose fibers or portions of cellulose fibers.

[0053] The cellulosic fibrous materials may also include non-wood pulps, such as straw pulp.

[0054] In some embodiments, the cellulosic fibrous material comprises or consists essentially of virgin wood pulp, such as virgin bleached chemical pulp that is substantially free of lignin, making the product particularly suitable for cooking, heating, and food contact, e.g., in a micro-oven.

[0055] In one embodiment, at least 90 wt%, such as at least 95 wt%, of the cellulosic fibrous material of the product consists of virgin cellulosic fibers, such as virgin wood pulp.

[0056] The advantage of virgin pulp is that it is free of pigments and other undesirable chemicals. Recycled waste often contains chemical and microbial contaminants that may affect safe use. Mixtures of chemical compounds and microbial products may leach from recycled materials and cause various adverse health or environmental effects. Not only the harmfulness of individual compounds but also interactions with other compounds and microbial products may increase the toxicity of recycled materials and their emissions. Therefore, the present invention preferably avoids the use of recycled materials.

[0057] An advantage of chemical pulps, such as bleached chemical pulp, is that they are substantially free of 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.

[0058] Lignin-containing pulps often have insufficient organoleptic properties for direct contact with food, and are susceptible to aging and yellowing of the material.

[0059] In one embodiment, the cellulosic fibrous material of the second fibrous layer comprises bleached softwood chemical pulp and bleached hardwood chemical pulp, such as 80-95 wt % bleached softwood chemical pulp and 5-20 wt % bleached hardwood chemical pulp.

[0060] In one embodiment, the cellulosic fibrous material of the second fibrous layer comprises 50-95 wt % bleached softwood chemical pulp.

[0061] In one embodiment, the cellulosic fibrous material of the second fibrous layer comprises 5-50 wt % bleached hardwood chemical pulp.

[0062] In one embodiment, the cellulosic fibrous material of the second fibrous layer comprises or consists of bleached softwood chemical pulp.

[0063] In one embodiment, the cellulosic fibrous material of the second fibrous layer comprises or consists of bleached hardwood chemical pulp.

[0064] The barrier properties may include one or more of oil and grease resistance, water resistance, water vapor resistance, fragrance resistance, gas resistance, oxygen resistance, and heat resistance.

[0065] Preferably, the barrier properties include water resistance, which is typically exhibited by the top fibrous layer.

[0066] Preferably, the barrier properties, such as oil and / or grease resistance, of the fibrous layer are obtained by mechanical treatment of the fibers. The mechanical treatment may be a treatment of the fibers in the fibrous furnish, which treatment is configured to increase the density of the layer formed, such as a treatment to increase the Shopper-Riegler number of the fibers. The Shopper-Riegler value may be obtained by standard method EN ISO 5267-1.

[0067] In one embodiment, barrier properties are provided to the fibrous layer by incorporating mechanically treated cellulose and / or lignocellulosic fibers, such as mechanically produced MFC (microfibrillated cellulose), NFC (nanofibrillated cellulose) or grub pulp.

[0068] The first fibrous layer may form the bottom fibrous layer of the product when in use, and the second fibrous layer may form the top fibrous layer of the product when in use. For example, when the product is a container, the contents of the container are in contact with the top layer of the product, while the bottom layer is furthest from the contents, usually on the surface.

[0069] The top fibrous layer may be further coated with one or more non-fibrous layers, which will form the top layer of the product.

[0070] Similarly, a bottom fibrous layer may be positioned over one or more non-fibrous layers, which form the bottom layer of the product.

[0071] Where the article is a container, holder, or support structure, the second fibrous layer may be configured to be in direct contact with the contents of the container, holder, or support structure.

[0072] The second fibrous layer may be configured to be in direct contact with the food, liquid, or beverage, or at least form the closest fibrous layer to the food, liquid, or beverage, which often contain oils, grease, and / or water that must be avoided from penetrating the fibrous layer of the product.

[0073] Preferably, the first and / or second fibrous layer, in particular the second fibrous layer, is oil and grease resistant throughout its entire structure. Alternatively or additionally, the first and / or second fibrous layer, in particular the second fibrous layer, is substantially water resistant throughout its entire structure.

[0074] In one embodiment, the oil and grease resistance OGR of the product or fibrous layer is at a "moderate" level or higher, as measured by ASTM F119 using olive oil at 60°C.

[0075] In one embodiment, the moisture permeability of the product or fibrous layer is at or below a "moderate" level as measured by ISO 2528 and ASTM E96 at standard conditions of 23° C. and 50% RH.

[0076] In one embodiment, the water absorbency on the barrier side of the product is at a "medium" level or less as measured by ISO 535, Cobb value after 3 minutes.

[0077] The first fibrous layer may be configured to be in direct contact with an exterior surface upon which the product is placed.

[0078] Typically, the first fibrous layer forms the bottom fibrous layer of the product and has a lower resistance to oils and greases than the second fibrous layer. The bottom fibrous layer of the product is typically not configured to come into direct contact with oily substances such as food.

[0079] In one embodiment, the bottom fibrous layer of the product is resistant to water and / or water vapor. Such barrier properties may be desirable, for example, to protect the product from direct contact with ambient water and moisture during storage and transportation of the product.

[0080] The product may include one or more, for example 1 to 10, inner fibrous layers between the first and second fibrous layers, each layer comprising cellulosic fibrous material, preferably comprising a chemical pulp, such as softwood pulp, and / or a mechanical pulp, such as bleached chemi-thermomechanical pulp (BCTMP). Products intended for heating or storage in high temperature environments preferably do not comprise mechanical pulp.

[0081] In one embodiment, the article includes three fibrous layers: a first and a second fibrous layer with a single inner fibrous layer therebetween.

[0082] In one embodiment the product is an ovenable product.Preferably the product comprises one or more inner layers comprising or consisting of a mechanical pulp such as BCTMP.

[0083] The top fibrous layer and / or the bottom fibrous layer may include bleached chemical pulp.

[0084] One or more of the inner fibrous layers may include mechanical pulp.

[0085] The barrier properties of the product, and in particular its fibrous layer, can be enhanced in a variety of ways.

[0086] In one example, refining of the fibrous starting material is used to densify the final product and obtain barrier properties for desired layers.

[0087] The top fibrous layer may comprise refined wood pulp, such as refined softwood chemical pulp, refined hardwood chemical pulp, such as refined birch or eucalyptus chemical pulp, or any combination thereof. The pulp is preferably bleached.

[0088] The cellulosic fibrous material of the second fibrous layer may comprise cellulosic fibers refined to a Shopper-Riegler number greater than 40, such as greater than 60, such as greater than 70, such as greater than 80.

[0089] The cellulose fibrous material of the bottom fibrous layer and / or the inner fibrous layer may comprise unrefined cellulose fibers or cellulose fibers that are less refined than the refined cellulose fibers of the top fibrous layer.

[0090] For example, the Shopper-Riegler number of the bottom textile layer and / or one or more inner textile layers of the product may be less than 60, for example less than 50, for example less than 20, such as in the range of 10-30.

[0091] For example, the Shopper-Riegler number of the bottom textile layer and / or one or more of the inner textile layers of the product may be between 10 and 50.

[0092] For example, the Shopper-Riegler number of the top fiber layer may be greater than 40, such as greater than 50.

[0093] For example, the Shopper-Riegler number of the bottom fiber layer can be greater than 10, such as greater than 15.

[0094] In one embodiment, the density of each fiber layer is 100 kg / m 3 Greater than.

[0095] In some embodiments, the density of the second fibrous layer is greater than the density of the first fibrous layer. In one embodiment, the density of the second fibrous layer is greater than 100 kg / m 3 Preferably, the density of the second fibrous layer is between 500 and 950 kg / m, calculated as dry solid weight per volume. 3, e.g. 600 kg / m 3 Ultra-high, 300~1000kg / m 3 The range is.

[0096] Preferably, the density of the first fibrous layer is greater than or equal to 400 kg / m 3 Less than 300 kg / m 3 Less than 500kg / m 3 and the density of the second fiber layer is less than 800 kg / m 3 Over 500kg / m 3 It's super.

[0097] The density of the second fibrous layer may be substantially uniform throughout its structure.

[0098] In another example, suitable additives or chemicals are added to the fiber starting material to impart barrier properties to the final product, for example to a particular fiber layer of the final product.

[0099] Both refining and the addition of barrier agents may be utilized to achieve barrier properties specifically in one or more of the fiber layers.

[0100] Any of the fiber layers of the product may be provided with barrier properties by refining the fiber and / or adding a barrier additive. Different barrier properties may be provided to the fiber layers. For example, one of the fiber layers may exhibit oil and grease resistance, while another fiber layer may exhibit water resistance.

[0101] The additives or chemicals are preferably added to the fibrous furnish or slush prior to the foaming step, e.g. at a consistency of 0.5-15%, e.g. 2-10%, or to the foam which is mixed into a slush of fibres having said consistency prior to foaming.

[0102] The additives or chemicals are preferably added to the fibrous furnish or slush at a consistency of less than 5%, such as less than 2%.

[0103] At least one of the fibrous layers, such as the first and / or second fibrous layer, may include one or more of the following additives: pigments, such as talc, clay, and ground calcium carbonate; barrier agents; latex binders; water soluble binders, such as PVA, starch, CMC; and sizing agents, such as AKD.

[0104] The amount of additive may range from 0.01 to 30 wt%, such as from 0.01 to 10 wt%, for example from 0.1 to 8 wt%, such as from 1 to 5 wt%, calculated on the total dry weight of the fibrous layer.

[0105] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-5 wt % talc.

[0106] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-5 wt% clay.

[0107] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-5 wt % calcium carbonate.

[0108] In one embodiment, at least one of the fibrous layers, such as the first and / or second fibrous layer, comprises a barrier agent selected from the group of dispersion polymers, polyolefins, polyesters, other thermoplastic polymers, biodegradable polymers such as polylactic acid, starch and its derivatives, plastomers, elastomers, ethylene vinyl alcohol, and any derivatives, copolymers and mixtures thereof.

[0109] In one embodiment, at least one of the fibrous layers, such as the first and / or second fibrous layer, comprises 0.1-15 wt %, such as 0.1-10 wt %, such as 0.1-5 wt %, of a barrier agent, such as a dispersed polymeric barrier agent. Such barrier agents typically provide the barrier properties in question throughout the structure of the fibrous layer, particularly in the absence of refinement.

[0110] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-5 wt % of a polymer latex binder, such as styrene butadiene latex, styrene acrylate latex, polyvinyl acetate latex, or the like.

[0111] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-15 wt %, such as 0.1-5 wt %, polyvinyl alcohol (PVA).

[0112] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-20 wt %, such as 0.1-5 wt %, of starch.

[0113] The starch may be a native, modified, cooked or swollen cationic starch.

[0114] In one embodiment, one of the fibrous layers, such as the second fibrous layer, comprises 0.1-5 wt% CMC.

[0115] In one embodiment, at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-20 wt % inorganic filler.

[0116] In one embodiment, the fibrous layer of the product comprises less than 5 wt% inorganic filler, such as less than 1 wt%.

[0117] In one embodiment, all or at least one of the fibrous layers, such as the second fibrous layer, comprises 0.1-20 wt% of a reinforcing additive, such as nanocellulose or microfibrillated cellulose (MFC) or other reinforcing cellulose material.

[0118] Preferably, the fibrous layer of the product comprises less than 5 wt. %, such as less than 2 wt. %, of waxes, plastics and fluorochemicals. In one embodiment, the fibrous layer of the product comprises less than 2 wt. % of waxes. In one embodiment, the fibrous layer of the product comprises less than 2 wt. %, such as less than 1 wt. % of plastics. In one embodiment, the fibrous layer of the product comprises less than 2 wt. %, such as less than 1 wt. % of fluorochemicals. In some embodiments, the product is substantially free of waxes, plastics and fluorochemicals, especially plastics.

[0119] For ovenable applications, the additives and foaming chemicals may be selected from among additives approved for use in materials or packaging in contact with food and approved for ovenable food packaging intended for heating. Preferably, the additives are selected from among those approved in BfR XXXVI / 2 "Paper and board for bakery use": https: / / bfr.ble.de / kse / faces / resources / pdf / 362-english.pdf.

[0120] For products not intended for ovens, the additives and foaming chemicals may be chosen more freely from all additives approved for use in materials or packaging in contact with food. Additives may include water-based barrier additives.

[0121] The amount of barrier additive may be in the range of 1-15 wt%, such as 1-10 wt%, such as 5-8 wt%, calculated on the total dry weight of the fibrous layer.

[0122] "Food contact material" refers to all materials and articles, such as packaging and containers, that are intended to come into contact with food.

[0123] Preferably, the product complies with Regulation (EC) No 1935 / 2004.

[0124] In one embodiment, the first fibrous layer and / or the second fibrous layer includes a sizing agent, such as modified rosin, wax, oil, or polymer. The advantage of using a sizing agent is that it can reduce the undesirable absorption of liquid and / or water and / or moisture into the foamed molded structure. This improves the moisture or water resistance of the product.

[0125] An example of a wax is alkyl ketene dimer (AKD). An example of an oil is alkenyl succinic anhydride (ASA). An example of a polymeric sizing agent is styrene acrylate emulsion (SAE).

[0126] A preferred sizing agent is AKD or a similar wax.

[0127] Sizing agents applicable to some embodiments of the present invention may be cationic or anionic surface sizes. In addition, or as an alternative, some reactive sizing agents such as alkyl ketene dimers (AKDs) may be used as surface sizes.

[0128] Suitable cationic sizes include cationic starch and starch derivatives, as well as the corresponding carbohydrate-based natural polymers. Among the synthetic polymers, for example, styrene / acrylate copolymers (SA), polyvinyl alcohol, polyurethanes, and alkylated urethanes may be used.

[0129] Suitable anionic sizing agents include anionic starches and starch derivatives, as well as 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, polyurethanes and similar latex products containing the same chemical functional groups.

[0130] In one embodiment, the sizing agent comprises alkyl ketene dimer (AKD).

[0131] In one embodiment, additives such as pigments, binders, and sizing agents are compatible with ovenable products.

[0132] In some embodiments, the product has a mass of, for example, 100 to 900 g / m 2 For example, in the range of 200-400g / m 2 or 400~600g / m 2 In the range of 5 to 900 g / m 2 The dry basis weight ranges from 1.0 to 1.0.

[0133] In one embodiment, the bottom and / or inner fibrous layers of the product have a fiber density of 100 to 400 g / m 2 For example, 230~270g / m 2 80~400g / m 2 The dry basis weight ranges from 1000 to 15000.

[0134] In one embodiment, the bottom and top fibrous layers of the product each have a fiber density of 80 to 150 g / m 2 The dry basis weight ranges from 1.0 to 1.0.

[0135] In one embodiment, the inner fibrous layer of the product has a fiber thickness of 150 to 250 g / m 2 The dry basis weight ranges from 1.0 to 1.0.

[0136] In one embodiment, the density of the inner fibrous layer is 100 kg / m 3 Greater than.

[0137] In one embodiment, the second fibrous layer of the product has a fiber density of, for example, 60 to 150 g / m 2 , or for example 20 to 60 g / m 2 , for example 30-50g / m 2 10~150g / m 2 The dry basis weight ranges from 1.0 to 1.0.

[0138] In some embodiments, the product may include 2-20 fiber layers, for example at least 3 fiber layers.

[0139] In some embodiments, the molded multi-layered fibrous product further comprises a release layer as the top layer of the product. The release layer is advantageous in baking applications, such as bread pans. Furthermore, the presence of the release layer can protect the fibers of the first and second fibrous layers from heat.

[0140] The product may include a non-fibrous release layer on top of a top fibrous layer, such as a second fibrous layer, which release layer forms the top layer of the product in use. In this case, the product may include 1 to 10 fibrous layers, preferably at least one of the layers exhibits barrier properties.

[0141] Typically, the non-fibrous release layer is configured to directly contact the food or liquid and to facilitate the release of the food or liquid from an article such as a container after it has been heated within the container.

[0142] In some embodiments, the product includes an intermediate layer, such as a pre-coating layer, between the release layer and the second fibrous layer. The intermediate layer may include or consist of PVA, CMC, starch, or combinations thereof.

[0143] An advantage of using an intermediate layer between the release layer and the fibrous layer is that intermixing of the release layer material with the fibrous structure may be avoided.

[0144] The method of the present invention makes it possible to obtain a smooth product surface, thereby reducing the amount of material required to prepare the release layer.

[0145] For example, the release layer can include a silicone composition, such as a sprayable silicone composition. The silicone composition can include an emulsion or a solventless system.

[0146] The silicone composition may contain cured modified silicone with very low surface tension and good insulating effect. The modified silicone component may be crosslinked by platinum catalyst. The product obtains high temperature resistance.

[0147] The intermediate layer and release layer are usually applied after hot pressing and then dried.

[0148] The dry basis weight of the release layer is 2.0 g / m 2 Less than 0.5 to 2.5 g / m 2 The range may be:

[0149] 1 shows a schematic diagram of a multi-layered textile product according to at least some embodiments of the present invention. The product includes a first textile layer 1, which is a bottom textile layer, a second textile layer 2, which is a top textile layer, and an inner textile layer 3 between the first textile layer 1 and the second textile layer 2. In addition, the product includes a non-textile peeling layer 5, which is a top layer of the product, and an intermediate layer 4 between the non-textile peeling layer 5 and the top textile layer 2 of the product. One or more of the textile layers 1, 2, 3 may exhibit barrier properties.

[0150] In another embodiment, the product includes only one fibrous layer, such as the first fibrous layer 1, a non-fibrous peeling layer 5, and optionally an intermediate layer 4.

[0151] In yet another embodiment, the product does not include a release layer or an intermediate layer.

[0152] In some embodiments, the product does not include an inner fibrous layer, while in other embodiments, the product includes one, two or three inner fibrous layers between the first fibrous layer 1 and the second fibrous layer 2.

[0153] A multi-layer product is preferably obtained in such a way that all the fibers contained in the final structure are subjected to the foaming process, in some embodiments all the fibers contained in the layer exhibiting barrier properties are subjected to the foaming process.

[0154] 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 a top fibrous layer, a bottom fibrous layer and / or one or more inner fibrous layers.

[0155] The advantage of foam molding is that it can produce lighter and bulkier products. In addition, it can achieve a more homogeneous molding. The use of foams makes it easy to produce multi-layer structures in a batch process; that is, all layers can be formed in the same mold to form a multi-layer stack in the mold, which is then hot pressed.

[0156] The advantage of dehydrating the entire multi-layer structure in the same mold is that the bonds between the layers may be stronger during dehydration as compared to dehydrating the layers individually.

[0157] In some embodiments, in addition to the foam-forming layer, the final product may further include a water-formed layer. Such one or more water-formed layers may be formed in a separate process and may be combined with the foam-forming layer or foam-forming multi-layer structure by hot pressing. The advantage of water-forming is the simplicity of preparing flat or planar structures. In the water-forming method, the individual layers are usually formed and removed from the mold independently of each other. Separate molds may also be used. After removal from the mold, the layers may be stacked and bonded to each other and / or other layers by hot pressing.

[0158] In one embodiment, the product comprises several fibrous layers prepared by a water-molding process, bonded together and optionally added to at least one foamed fibrous layer, advantageously one or more of which constitute the top and / or bottom fibrous layer of the product and advantageously exhibit barrier properties.

[0159] Preferably, the product is a three-dimensional molded multi-layer textile product obtained by using a mold comprising at least one three-dimensional non-planar mold surface, said product exhibiting a three-dimensional shape that conforms to the shape of said three-dimensional non-planar mold surface.

[0160] For example, the product may have the shape of a cup, a plate, a bowl, a pot, a clamshell, or a tray.

[0161] Typically, the product is a food or liquid package or container, or a food or liquid serving product such as a beverage cup, food tray or plate, baking pan, or disposable lasagna tray mold product.

[0162] In some embodiments the product is ovenable, for example ovenable up to a temperature of at least 100°C, preferably at least 220°C.

[0163] In some embodiments, the product is a micro-oven compatible food or liquid package or container, such as a food tray.

[0164] In one example, the product is a baking vessel such as an oven-safe pan.

[0165] The product may be used to package, store, serve, cook and / or heat food, liquids and beverages.

[0166] More generally, the product may be used for packaging and storing oil-containing and / or water-containing products.

[0167] The product may be intended for use or installation on greasy, oily, and / or wet surfaces, or in moist environments.

[0168] Below are examples of multi-layer product structures suitable for specific applications.

[0169] In one example, the top fibrous layer of the product is a barrier layer, such as a water-resistant barrier layer. The product can be a fruit package. The barrier function is to prevent wetting of the package and the associated deterioration of the appearance of the package.

[0170] In one example, the top fibrous layer of the product is a barrier layer, such as an oil- and grease-resistant barrier layer. The product can be a package for oily foods. The barrier function is to prevent oils and greases from penetrating into the package, such as during transportation or heating.

[0171] In one example, the bottom fibrous layer of the product is a barrier layer, such as a moisture and / or water vapor barrier layer. The product can be packaging for food, such as dry food. The barrier function is to prevent moisture and / or water vapor from penetrating into the package, such as during transportation in tropical conditions.

[0172] In one example, the bottom fibrous layer of the product is a barrier layer, such as a moisture and / or water vapor barrier layer. The product can be a package for a food product, such as a frozen food. The barrier function is to prevent moisture from the frozen food from penetrating out through the package, which can lead to the product drying out during storage in the freezer.

[0173] The molded multi-layer fibrous product may be used as, or as part of, a food or liquid package, or a food or liquid serving product, or a baking product.

[0174] One embodiment provides a product obtained by the following process:

[0175] In some embodiments, the product or at least one of its fiber layers may be obtained by a method comprising the steps of providing a fiber slash comprising fibers, refining the fibers of the fiber slash and / or adding a barrier agent to the fiber slash, preparing the fiber slash into a foamed composition, forming the foamed composition in a mold, such as by molding and pressing, dewatering, and hot pressing.

[0176] Alternatively, the barrier agent may be added at a later stage in the process, for example by applying a composition containing the barrier agent to an already formed layer, preferably a foamed layer.

[0177] In this method, a foam composition is first provided that includes fibers, water, air, and one or more foaming chemicals. The foam may further include fillers, additives, pigments, binders, barrier dispersants, and sizing agents.

[0178] The foaming chemicals, such as surfactants, used may be nonionic, anionic, cationic, or amphoteric. A suitable amount of surfactant is about 150-1000 ppm by weight. An example of an anionic surfactant is alpha olefin sulfonate, and an example of a nonionic surfactant is PEG-6 lauramide. A specific example is sodium dodecyl sulfate.

[0179] Typically, the size (diameter) of the cells in the foam is about 10 to 300 μm, for example, 20 to 200 μm, and usually about 20 to 80 μm.

[0180] In one embodiment, a composition suitable for foaming is obtained by mixing a fiber slush having a consistency (amount of fiber relative to the weight of the slush) of about 0.5-7% by weight with a foam formed from water and surfactants, the air content of which is about 10-90% by volume, such as, for example, 20-80%, 50-70% by volume, in this case a foamed fiber slush is produced having a fiber content of about 0.1-3% by weight.

[0181] The fibers may include any type of fiber from chemical and / or mechanical pulping, recycled fibers, shredded fibers, agricultural waste streams, fibers from annual plants, by-products, micro- or nanofibrillated cellulose fibers and regenerated cellulose fibers, and combinations thereof.

[0182] In one embodiment, the molded multi-layer fibrous product is obtained by a method comprising forming a molded multi-layer foamed structure from at least one foamed fibrous composition comprising cellulose fibers, water, air and a blowing agent, and optionally also a barrier agent, dewatering the structure, preferably by applying a vacuum, and hot pressing the dewatered structure to obtain a molded multi-layer fibrous product, wherein at least one of the fibrous layers of the multi-layer fibrous product exhibits barrier properties substantially throughout its structure.

[0183] As used herein, "forming", typically foam molding, refers to the process of imparting a foam composition to a shape, such as a three-dimensional shape, within a mold.

[0184] In a preferred method, the foamed fiber composition is fed into a mold, typically into a cavity within the mold. The mold typically comprises a cavity or interior space defined by the inner surface of the mold. Within the cavity, the foamed composition is molded. The cavity may have dimensions, such as a shortest dimension, in the closed configuration of the mold in the range of 0.1 to 100 mm, for example 5 to 100 mm, preferably 5 to 60 mm.

[0185] The foaming composition may be provided to a mold to provide a quantity of the foaming composition, e.g., a layer of the foaming composition, on at least one interior surface of the mold, which layer is typically non-planar and may be understood as a thickness, e.g., a substantially constant thickness, of the foaming composition present on the interior surface of the mold and conforming to the shape of that surface.

[0186] Typically, the molding step involves pressing the fiber composition in the interior space of a mold by bringing parts of the mold closer together.

[0187] The step of forming a multi-layer foamed structure may include providing a first fiber composition in a foamed form to a mold and molding the first fiber composition in the mold to prepare a first foamed fiber layer. Then, without removing the first fiber layer from the mold, the process continues by providing a second fiber composition in a foamed form to the mold and molding the second fiber composition in the mold to prepare a second foamed fiber layer. As a result, a two-layer foamed structure is obtained in the mold.

[0188] Unless otherwise specified, "part of the mold" refers to the part of the mold that serves to define the interior space and thus contributes to shaping the foamed fiber composition.

[0189] The second expanded fiber layer can be delivered and placed in the mold on top of or below the first expanded fiber layer, and the delivering steps can be performed in either order, with either the first layer or the second layer being formed in the mold first.

[0190] It is also conceivable that the product is obtained by using separate molds to prepare the first and second foamed fiber layers, and the obtained first and second fiber layers are bonded in the hot pressing step.

[0191] In one embodiment, said providing to the mold comprises providing the foamed fiber composition in foamed form to an interior space or volume of the mold, said interior space being bounded by the interior surface of the mold.

[0192] The application of a vacuum in the dehydration step is preferably possible.

[0193] The final multi-layer foam structure is removed from the mold by opening the mold.

[0194] 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.

[0195] Before starting to feed further, such as the second fiber composition, into the mold, it is usually necessary to move the parts of the mold away from each other to expand the interior space of the mold, the volume of which can be reduced or expanded to mold the foam already fed and to make room for the foam to be fed next, respectively.

[0196] When adjusting the volume of the interior space of the mold, some parts of the mold may remain stationary while other parts move.

[0197] In one example, during said approaching or said expanding, one or more portions of the mold remain stationary and one or more other portions of the mold move.

[0198] For example, a mold may include two sub-molds, such as two half-molds, arranged opposite each other and movable relative to each other. The sub-molds may be brought closer together to mold the product. The sub-molds may be moved away from each other to enlarge the interior space, or moved further apart to open the mold and remove the molded product from the mold.

[0199] In one example, the product may be obtained by using a mold with two parts, a negative mold and a positive mold, which may be arranged facing each other to enclose the internal space, also called the molding space or mold cavity, between the two parts. The composition to be molded or formed 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 in which the internal space is reduced by moving one or both of the positive and negative molds.

[0200] Dehydration of the structure may be carried out by applying a vacuum to the interior space of the mold containing the dispensed foam composition.

[0201] The dehydration step is performed before the hot pressing step, which results in the final, usually dry, product in which all layers are bonded together. In the hot pressing, the temperature is usually higher than 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.

[0202] The hot pressing may include two successive hot pressing steps.

[0203] During hot pressing, heat can be applied from one or both sides of the material being pressed.

[0204] For example, the hot pressing may include two hot pressing steps where both heats are applied from the same side, or the hot pressing may include two hot pressing steps where heats are applied from different sides.

[0205] Hot pressing may contribute to the development of barrier properties through chemical reactions that occur at elevated temperatures, such as crosslinking and curing reactions, and therefore may be advantageous when using barrier chemistries such as AKD. EXAMPLES

[0206] (Example)

[0207] In the following, an embodiment will be described in which the product is obtained using a two-part mold, called a pair of molds.

[0208] Any of the features and combinations of features described below may be combined with the embodiments and alternatives previously described in this application.

[0209] This method is for forming a fiber molded article. In this method, a layer is formed with the foam. The layer is part of the final product. The foam, also called a "foam composition", contains fiber, water, air, and one or more foaming chemicals. The foam may also contain fillers and other conventional papermaking chemicals such as additives, pigments, colorants, binders, etc.

[0210] The fibers may include any type of cellulosic and / or lignocellulosic fibers from chemical and / or mechanical pulping, recycled fibers, shredded fibers, by-products, micro- or nanofibrillated cellulose and regenerated fibers, and combinations thereof.

[0211] The recipe of a single foam layer may consist of any selected mixture of the aforementioned raw materials. Naturally, the recipes of the different layers may differ from each other.

[0212] The layer is formed by a pair of molds, which may consist of several part molds, each for one product.

[0213] As a rule, one mould is a negative mould and the other a corresponding positive mould. In this way, a three-dimensional shape is obtained during the formation of the layer. The water and air in the foam must be removed. This is mainly done by shortening the distance between the moulds and applying pressure. The pressure forces the air and water out of the foam fed between the moulds. The porous surface of the mould (product surface) provides an escape route for the water and air while the fibres form a residual layer.

[0214] The foam can be fed through one of the moulds, which are spaced apart from each other and have a closed cavity for the foam, which allows for faster feeding and more flexible timing choices.

[0215] Foam can be fed through both molds.

[0216] In this example, the pair is formed of an upper and lower mould, the upper mould being movable whilst the lower mould being fixed, and the foam is fed through the lower mould.

[0217] The foam can be dispensed when the pairs are apart from each other or when the pairs are moving relative to each other, thereby shortening the forming cycle. For example, foam can be dispensed even when the upper mold is rising. On the other hand, the pairs can be first moved away from each other and only then start dispensing foam.

[0218] By passing the foam through the mould, an additional advantage is provided: it is now possible to form not only a single layer, but also multiple layers by the lamination process. The formed layer can be removed from the inside of the pair after formation. Alternatively, after the layer is formed, the pair can be moved away from each other and more foam can be provided for the further layer, after which the pair can be brought closer together again. Again, foam can be provided already when the pair is apart from each other.

[0219] In practice, 1 to 10 further layers, advantageously 2 to 4 further layers, can be formed. After forming and pressing, the air and unbound moisture are removed and a semi-finished product is obtained.

[0220] The next step is hot pressing to remove any water that may be bound to the fibers. The hot pressing step finally bonds the layers together. Additionally, the high temperature may develop and / or exhibit barrier properties.

[0221] Surprisingly, after the first layer, further layers may be formed on either side of the textile. In other words, the foam may be provided on either side of the preceding layer. For example, one inner layer may be formed first to function as a body layer, and then one further layer may be formed on either side of the inner layer to function as a surface layer. Thus, there are three layers in total.

[0222] Other methods can also be used to create multi-layer products. A product can combine multiple partial products obtained from two separate mold pairs. The partial products formed from these two pairs can be combined and hot pressed to obtain a single product. For example, in one pair, one inner layer with one bottom layer can be formed. Simultaneously with the other pair, one inner layer with one top layer can be formed. When these layers are combined, a four-layer product is formed.

[0223] The rapid formation of multiple layers to construct one product is a great advantage. The foam can be replaced before forming one or more additional layers after the first layer. Foams with different properties can be used to form one product. In this way, each layer can be different from each other. The product can, for example, include one or two inner layers formed from one type of foam. In that case, there can be at least one outer layer of another type of foam. Thus, the foam can change the cross-sectional shape of the product.

[0224] Surprisingly, the textile product can be formed without additional heating. Because the foam has a low moisture content and a high air content, moisture can be removed efficiently and the product retains its shape after formation. At the same time, the foam maintains its shape and consumes low power.

[0225] The temperature of the foam is maintained in the range of 15-45° C., advantageously in the range of 25-35° C. If necessary, the foam and / or the mold may be cooled to keep the temperature stable and sufficiently low.

[0226] At such low temperatures, the fibers of the product remain moisture-containing. During hot pressing, moisture is expelled as water and steam, which also provides a smooth surface and contributes to internal bonding to form a solid layered product. Additionally, barrier properties may develop and / or be expressed at the elevated temperatures applied during hot pressing.

[0227] As soon as the pairs start to move away from each other, foam is fed into the mould interior. When the pairs move towards each other again, the feeding stops and the water is drained from the pairs, simultaneously removing the air.

[0228] Removal of water and air by pressing may be aided by a vacuum.

[0229] Although a single layer product may be formed, the method is advantageous when multiple layers are formed.

[0230] Foams are made from water, air, fibers, and foaming chemicals. Foams contain small pieces or particles of the fibers that matter. Foaming chemicals are also used to accelerate the foam production and to maintain the shape of the foam.

[0231] The fibres can vary greatly in their origin and composition: for example, wood fibres or vegetable fibres (such as straw, bagasse and bamboo fibres) can be used, but also man-made cellulose fibres.

[0232] In a proper foam, the water, fibers, and additives are uniformly distributed in the foam's cell walls. Foam is a non-cohesive, heterogeneous fibrous material, and the air in the foam carries the fibers and other ingredients into the forming process. The use of foam also provides very high fiber retention. In fact, over 99% of the fibers remain in products formed from thick foam as a carrier medium.

[0233] The additives may have different retention characteristics depending on the purpose. Retention aids may be added.

[0234] By forming the textile product in multiple layers, the product properties can be tailored in various ways. For example, the base structure and the surface properties of the product can be formed with different foam compositions. In fact, each layer can have its own process parameters and raw materials. For example, the rigid body of the product can be formed with cheaper fibers, while the surface layers can be formed with higher quality fibers. Compared to known processes using aqueous fiber slurries, the fiber density is much higher in the foam. At the same time, the amount of water in the circulating cell walls is also significantly lower, making it easier to remove the water during formation. Foams with a lower amount of water allow for faster process cycles.

[0235] There may be cases where it is possible to interchange the proportions or types of foam in different layers of the product.

[0236] The foam can be fed into the mould cavity quickly enough, especially if a vacuum is used.

[0237] In a proper foam, the air bubbles do not separate and the fibers are evenly distributed. During formation, the foam is distributed or fed into the mold interior space between the two molds. The volume of the mold interior space can be adjusted depending on the required layer thickness.

[0238] For example, the formation of the next layer can take place on either side of the previous layer, and it may be the case that foam feeding has already begun while the pair is separating, which is advantageous because during separation the mold space is instantly filled with foam, without air being able to enter the space in front of the foam.

[0239] The foam is fed through the mold into the mold inner space. The "mold inner space" refers to the space between a pair of molds.

[0240] Vacuum may also be used. Vacuum helps in removing water and air. Vacuum may be applied even during foam feeding, or at the latest when the pairs start to approach each other. During forming, the mold space decreases, but not as much as in the actual pressing step after forming. Furthermore, it is possible to hold the formed layer under vacuum on the desired mold surface (inner surface) and form additional layers on selected sides of the previous layer.

[0241] Forming can be done without heating in order to control the optimal foam structure for uniform formation of the product. In practice, forming is done at a substantially constant process temperature, advantageously 15-45°C. In addition to the pair of molds, this temperature can also be maintained throughout the foaming system, ensuring optimal cell size for high product quality. In this way, the life of the foam can be extended. Also, it is easier to remove air than steam, the layers are not damaged and the process is stable. In practice, the foam contains more than 50% air, advantageously 55-75% air.

[0242] The optimal bubble size of the foam upon formation may be about 10 to 500 μm in diameter, preferably 50 to 150 μm in diameter.

[0243] Surprisingly, the foaming process of the present invention simultaneously achieves high consistency and good formation compared to known aqueous slurry forming processes, which require longer heating and dewatering times due to much lower consistency and poor formation due to agglomeration.

[0244] The laminated products are formed as layers on top of each other, and pressing and dewatering are finally carried out through a mold with the previous layer below. The layer structure is bonded at the latest by hot pressing.

[0245] The laminated product can be formed in any order required, in other words starting from any of the inner layers or from any of the outer layers.

[0246] Bonding of the layers to one another is ensured by dehydration through the layer interfaces.

[0247] The bonding of the layers continues in a subsequent hot pressing step, where the heat and steam generated within the product and steam passing through the layers also strengthens the bond between the layers. During the hot pressing step, the barrier chemical may become further and / or more uniformly distributed within one or more of the fibrous layers.

[0248] The layering may be performed with the same fibers, but different additives may be used in the different layers.

[0249] The hot pressing may include multiple separate hot pressing stages. Hot air or radiant heating or impulse drying, preferably impulse drying, may be applied to hot press and / or dry the product.

[0250] The hot pressing step may be followed by an optional additional drying step at elevated temperature to cure added chemicals such as AKD, barrier agents, etc. Such additional drying is also advantageous when the product includes a non-fibrous release layer (typically comprising silicone).

[0251] The method includes producing a foam from fibers, water, air, and foaming chemicals. As mentioned above, the properties of the foam can be varied. Furthermore, the method includes using a pair of molds with varying distances from each other. In other words, the distance between the molds, i.e., the volume of the internal cavity, can be varied. In practice, after the foam is dispensed, the molds are pressed together to remove the water and air, thereby forming the product.

[0252] Additionally, the method further includes feeding foam between the molds to form a layer. A single layer may constitute the product, but advantageously the product may include multiple layers. Foam may be fed when the molds are spaced apart from each other, or when the pair of molds are moved relative to each other. This shortens the process cycle and provides more options in tailoring the process and the product.

[0253] The method may include creating a closed mold space and feeding a quantity of foam into the mold space as a closed cavity. The product is removed from the pair and transferred to a hot press.

[0254] Advantageously, the pair comprises an upper mould and a lower mould, the upper mould being movable and the lower mould being fixed.

[0255] In a closed mold space, the molds can move apart during formation. After moving apart, the pair provides space for additional foam to enter.

[0256] In practice, the distance between the dies is 10-100 mm, preferably 20-60 mm. Generally, the thicker the layer, the longer the distance. The foam flow rate is kept moderate. In practice, the flow rate is 1-3 meters per second.

[0257] As previously mentioned, several identical products can be obtained in parallel by a forming method in which each mould pair comprises several identical partial moulds or sub-moulds.

[0258] Each part or sub-mold is filled evenly with foam, so the product is uniform and the process is quick.

[0259] After the mold cavity is filled with foam, it is pressed to remove water and air. Water and air can pass through the mold surface while the fibers accumulate on the mold surface. Water removal can be aided by vacuum. Water removal can also be aided by overpressure applied by an opposing mold.

[0260] 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 as recognized by those skilled in the relevant art. It is also to be understood that the terminology used herein is used only for the purpose of describing particular embodiments, and is not intended to be limiting.

[0261] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that 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.

[0262] As used herein, a plurality of items, structural elements, components, and / or materials may be presented in a common list for convenience. However, these lists are to be construed as if each element of the list were individually identified as a separate and unique element. Thus, the individual elements of such lists should not be construed as being de facto equivalents to other elements of the same list solely based on their appearance within a common grouping, absent a contrary indication. Furthermore, various embodiments and examples of the invention may be referenced herein along with alternatives for the various components thereof. It is to be understood that such embodiments, examples, and alternatives should not be construed as de facto equivalents of each other, but should be considered as separate and autonomous representations of the invention.

[0263] 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 provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. However, one of ordinary skill in the 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 some cases, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the invention.

[0264] While the foregoing examples illustrate the principles of the invention in one or more particular applications, it will be apparent to those skilled in the art that numerous changes in form, use, and details of implementation may be made without affecting the inventive step and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0265] In this document, the verbs "comprise" and "include" are used as open limitations that do not exclude or require the presence of unmentioned features. Features recited in the dependent claims may be freely combined with each other, unless expressly stated otherwise. Furthermore, it is to be understood that the use of "a" or "an", i.e. the singular, throughout this document does not exclude the plural. [Industrial Applicability]

[0266] The present invention is industrially applicable at least in the production of multi-layer fiber molded articles.

[0267] BCTMP Bleached Chemi-Thermo-Mechanical Pulp MFC Microfibrillated Cellulose NFC Nanofibrillated cellulose [Explanation of symbols]

[0268] 1. First Fiber Layer 2 Second fiber layer 3. Inner fiber layer 4. Middle Tier 5. Non-fiber peeling layer

Claims

1. An oven-compatible formed multi-layer fiber product, comprising: a first fiber layer containing a cellulose fiber material; a second fiber layer on top of the first fiber layer, the second fiber layer containing a cellulose fiber material, the second fiber layer on top of the first fiber layer; the first and / or the second fiber layer exhibits barrier properties substantially throughout its structure; the product is an oven-compatible formed multi-layer fiber product configured to heat food or a liquid thereon to at least 100°C, more preferably at least 220°C.

2. The product further comprises a non-fiber release layer on top of the second fiber layer, which forms the uppermost layer of the product during use; the non-fiber release layer is in direct contact with food or a liquid and is configured to facilitate the release of food or a liquid from the product after being heated thereon. The oven-compatible formed multi-layer fiber product according to Claim 1.

3. The oven-compatible formed multi-layer fiber product according to Claim 1 or 2, wherein the non-fiber release layer contains a silicone composition.

4. The dry basis weight of the non-fiber peeling layer is less than 2.0 g / m ２ such as less than 0.5 to 2.5 g / m ２ , and is the oven-compatible molded multilayer fiber product according to claim 1 or 2.

5. The oven-compatible formed multi-layer fiber product according to Claim 1 or 2, wherein the first fiber layer forms the lowermost fiber layer of the product during use, and the second fiber layer forms the uppermost fiber layer of the product during use.

6. The oven-compatible formed multi-layer fiber product according to Claim 1 or 2, wherein the barrier properties include one or more of oil resistance, grease resistance, water resistance, water vapor resistance, aroma resistance, gas resistance, and oxygen resistance.

7. The oven-compatible formed multi-layer fiber product according to Claim 1, wherein the first and / or the second fiber layer is substantially oil-resistant and grease-resistant throughout its structure.

8. The oven-compatible formed multi-layer fiber product according to any one of Claims 1, 2, and 7, wherein the first and / or the second fiber layer is substantially water-resistant and / or water vapor-resistant throughout its structure.

9. The oven-compatible formed multi-layer fiber product according to any one of Claims 1, 2, and 7, further comprising one or more inner fiber layers each containing a cellulose fiber material between the first fiber layer and the second fiber layer.

10. The oven-compatible formed multi-layer fiber product according to any one of Claims 1, 2, and 7, wherein the second fiber layer forms the uppermost fiber layer of the product and has higher oil resistance and grease resistance than the fiber layer below it.

11. The first fiber layer forms the bottommost fiber layer of the product and has higher water resistance and / or higher water vapor resistance than the fiber layers above it, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

12. The cellulose fiber material of the fiber layer of the product contains or consists of bleached chemical wood pulp, preferably bleached softwood chemical wood pulp, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

13. The cellulose fiber material of the first and / or second fiber layer contains cellulose fibers refined to a Schopper-Riegler number exceeding 40, such as exceeding 70, exceeding 80, etc., preferably bleached softwood chemical wood pulp, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

14. The Schopper-Riegler number of the bottommost fiber layer and / or one or more inner fiber layers of the product is less than 50, such as less than 30, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

15. The density of the second fiber layer is greater than the density of the fiber layer below it. Preferably, the density of the second fiber layer, calculated as the dry solid weight per volume, is 600 to 950 kg / m ３ , 800 kg / m ３ super, etc., in the range of 300 to 1000 kg / m ３ of the oven-corresponding molded multi-layer fiber product according to any one of claims 1, 2, and 7.

16. The density of the lowermost fiber layer and / or one or more inner fiber layers of the product is less than 500 kg / m ３ The oven-compatible molded multilayer fiber product according to any one of claims 1, 2, and 7.

17. At least one of the fiber layers, preferably at least the second fiber layer, contains one or more of additives such as pigments, barrier agents, binders, sizing agents such as AKD, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

18. The product has a dry basis weight in the range of 5 to 900 g / m ２ , for example, in the range of 100 to 900 g / m ２ , in the range of 200 to 400 g / m ２ and is an ovenable molded multi-layer fiber product according to any one of claims 1, 2, and 7.

19. The fiber layer on the uppermost layer and / or the lowermost layer of the product has a basis weight in the range of 20 to 80 g / m ２ in the range of 30 to 50 g / m ２ in the range of 20 to 150 g / m, such as ２ the ovenable molded multi-layer fiber product according to any one of claims 1, 2, and 7.

20. The product is a three-dimensional molded multi-layer fiber product obtained by using a mold including at least one three-dimensional non-planar mold surface, the product exhibits a three-dimensional shape conforming to the shape of the three-dimensional non-planar mold surface, and preferably, the product is obtained by a foam-forming method or a water-forming method in the mold, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

21. The product is an ovenable or micro-ovenable food or liquid packaging or container or tray, or a baking or cooking container such as an ovenable pot, for the oven-compatible molded multi-layer fiber product according to any one of claims 1, 2, 7.

22. An oven-compatible molded fiber product including at least one fiber layer containing a cellulose fiber material, The first fiber layer exhibits barrier properties substantially throughout its structure, The product is configured to heat food or a liquid thereon to at least 100°C, preferably at least 220°C. The product further includes a non-fiber release layer that forms the uppermost layer of the product during use. The non-fiber release layer is in direct contact with the food or liquid and is configured to easily release the food or liquid from the product after heating. An oven-compatible molded fiber product comprising at least one fiber layer containing a cellulose fiber material.

23. Use of the oven-compatible molded fiber product according to any one of claims 1, 2, 7, 22 in baking, cooking and / or heating food or liquid.

24. Forming a single-layer or multi-layer foamed fiber structure from at least one foamed fiber composition comprising cellulose fiber, water, air and a foaming agent; Dehydrating the structure, preferably by applying a vacuum; Hot pressing the dehydrated structure to obtain a molded multi-layer fiber product; Obtained by a method comprising: wherein at least one of the foamed form fiber layers of the multi-layer fiber product exhibits barrier properties substantially throughout its structure. A molded multi-layer fiber product.

25. The step of forming the molded multi-layer foamed fiber structure comprises: Providing a first fiber composition; Providing a second fiber composition, the cellulose fibers of the second fiber composition being purified to a Schopper-Riegler number of greater than 40, preferably greater than 70; Supplying the first fiber composition in foamed form to a mold and molding the first fiber composition in the mold to prepare a first foamed fiber layer; Supplying the second fiber composition in foamed form to the mold and molding the second fiber composition in the mold to prepare a second foamed fiber layer and obtaining a two-layer molded foamed fiber structure, wherein the first foamed fiber layer is located either above or below the second foamed fiber layer in the mold, The product according to claim 24, wherein the supplying steps can be carried out in any order.

26. The product according to any one of claims 1, 2, 7, 22.

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