Oven-safe molded multilayer textile products and their applications

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] The present invention relates to molded textile products, and more particularly to multilayer molded textile products. [Background technology]

[0002] In known techniques for manufacturing molded textile products, foam is deposited in a tub-shaped mold with a headbox. Because the forming and pressing are performed in separate sequences, the forming and dewatering processes are slow, and the foam can spread unevenly in the mold. This method is mainly suitable for products such as filters or insulators. Typically, the resulting structure, such as an egg tray, is porous, and the surface is heterogeneous and rough.

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

[0004] It is also known that various barrier coating films are applied to packaging and containers made from two-dimensional fibrous materials such as cardboard. Such barrier coatings typically involve the use of plastic materials and films. The addition of barrier coatings may be carried out in a separate process after the actual fibrous substrate has been manufactured.

[0005] Individual barrier coating films have many drawbacks, including adhesion of the coating film to the rest of the product and deterioration of the mechanical properties of the coating film during the drying step in manufacturing or during humidity changes in transportation and storage.

[0006] In particular, oven-safe food containers and packaging are currently made from paper or cardboard materials, with a plastic or wax-based barrier coating on the food-contacting side of the container, such as a laminated or extruded barrier coating made of polyethylene terephthalate or polyethylene.

[0007] An object of the present invention is to solve at least some of the problems existing in the known art. SUMMARY OF THE INVENTION

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

[0009] According to a first aspect of the present invention, there is provided a shaped multilayer fiber product comprising: a first fiber layer comprising a cellulose fiber material; and a second fiber layer located on top of the first fiber layer, wherein the second fiber layer comprises a cellulose fiber material, and the first and / or second fiber layer preferably exhibits barrier properties substantially throughout the entire structure thereof.

[0010] Various embodiments of the first aspect may include at least one feature from the bulleted list below. · The first fiber layer forms the lowermost fiber layer of the product in use. · The second fiber layer forms the uppermost fiber layer of the product in use. · The second fiber layer is configured to be in direct contact with food or liquid. · The barrier properties include one or more of oil and grease resistance, water resistance, water vapor resistance, aroma resistance, gas resistance, and oxygen resistance. · The first and / or second fiber layer is substantially oil and grease resistant throughout the entire structure thereof. · The first and / or second fiber layer is substantially water resistant throughout the entire structure thereof. · The first and / or second fiber layer is substantially water vapor resistant throughout the entire structure thereof. · The cellulose fiber material comprises one or more of: chemical wood pulp, mechanical wood pulp, fibrillated cellulose such as microfibrillated cellulose and nanocellulose, and any other cellulose material comprising cellulose fibers or a portion of cellulose fibers. The cellulose fiber material comprises bleached or unbleached chemical pulp, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp. The cellulose fiber material comprises bleached or unbleached chemithermomechanical pulp. The first and / or second fiber layer of the cellulose fiber material comprises bleached or unbleached softwood chemical pulp and bleached or unbleached hardwood chemical pulp, such as 80 to 95 wt% of bleached or unbleached softwood chemical pulp and 5 to 20 wt% of bleached or unbleached hardwood chemical pulp. The product further comprises one or more inner fiber layers between the first fiber layer and the second fiber layer. Each inner fiber layer comprises a cellulose fiber material, and preferably comprises mechanical pulp such as bleached chemithermomechanical pulp (BCTMP). The uppermost fiber layer and / or the lowermost fiber layer comprises bleached chemical pulp. One or more of the inner fiber layers, if present, comprises mechanical pulp and optionally comprises chemical pulp. The uppermost fiber layer comprises refined softwood and / or hardwood chemical pulp. The lowermost fiber layer comprises refined softwood and / or hardwood chemical pulp, preferably comprises hardwood chemical pulp, and usually comprises refined hardwood chemical pulp. The second fiber layer forms the uppermost fiber layer of the product. The second fiber layer has higher oil resistance and grease resistance and / or higher water resistance and / or higher water vapor resistance than the fiber layer thereunder. The first fiber layer forms the lowermost fiber layer of the product. The first fiber layer has higher water resistance and / or higher water vapor resistance than the fiber layer thereabove. The cellulose fiber material in the first and / or second fiber layer comprises cellulose fibers refined to a Shopper-Riegler number of more than 40, such as more than 70, more than 80. The Shopper-Riegler number of the lowermost fiber layer and / or one or more inner fiber layers of the product is less than 50, such as less than 40, such as less than 30. • The density of the second fiber layer is greater than that of the fiber layer thereunder, preferably, the density of the second fiber layer, calculated as dry solid weight per volume, is 600~950kg / m 3 , 800kg / m 3 or more, within the range of 300~1000kg / m 3 . • The density of one or more inner fiber layers of the product is less than 600kg / m 3 , such as less than 500kg / m 3 . • At least one of the fiber layers, preferably at least the first and / or second fiber layer, comprises one or more of the following additives: pigments such as talc, clay or kaolin, heavy calcium carbonate, precipitated calcium carbonate, and titanium dioxide, colorants and fillers, barrier agents such as dispersion barrier agents, latex binders, water-soluble binders such as PVA, starch and CMC, and sizing agents such as AKD. • At least one of the fiber layers, preferably at least the first and / or second fiber layer, comprises PVA. • At least one of the fiber layers, preferably at least the first and / or second fiber layer, comprises AKD, ASA, or a resin adhesive, preferably AKD. • At least one of the first and / or second fiber layers comprises a barrier agent that provides the barrier property throughout the entire structure of the fiber layer, in an amount of preferably at least 0.5wt%, such as 1wt%. • The product has a dry basis grammage in the range of 5~900g / m 2 , for example in the range of 100~800g / m 2 , for example in the range of 200~600g / m 2 . • The uppermost fiber layer and / or lowermost fiber layer of the product has a dry basis grammage in the range of 50~200g / m 2 , for example 80~150g / m 2 . • The uppermost fiber layer and / or lowermost fiber layer of the product has a dry basis grammage in the range of 20~80g / m 2 , for example 30~50g / m 2 . Each fiber layer of the product is obtained by either foam molding or water molding in a mold, preferably by foam molding. • At least one, for example, at least two, preferably at least three, fiber layers of the product are obtained by foam molding. • At least the fibrous layer exhibiting barrier properties was obtained by a foam molding method within a mold. The product is a three-dimensional molded multilayer fiber product obtained by using a mold that includes at least one three-dimensional non-planar mold surface, and the product exhibits a three-dimensional shape that conforms to the shape of the three-dimensional non-planar mold surface. • The products are food or liquid serving products, such as food or liquid packaging, or liquid cups or food trays.

[0011] According to a second aspect of the present invention, the use of a molded multilayer fiber product according to the first aspect is provided as packaging for food or liquids, as a serving product for food or liquids, or as part thereof.

[0012] A third aspect of the present invention provides the use of a molded multilayer fiber product according to the first aspect in packaging, storing, serving, cooking and / or heating food or liquids.

[0013] A fourth aspect of the present invention provides a molded multilayer fiber product obtained by a method comprising the steps of: forming a molded single-layer or multilayer foam fiber structure from at least one foam fiber composition comprising cellulose fibers, water, air and a foaming agent; dehydrating the structure, preferably by applying a vacuum; and hot-pressing the dehydrated structure, along with any additional fiber layers, to obtain a molded multilayer fiber product, wherein at least one of the fiber layers of the multilayer fiber 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 for providing the said barrier properties. The step of forming a molded single-layer or multi-layer foamed fiber structure includes the steps of: providing a first fiber composition; providing a second fiber composition, which optionally includes purifying the cellulose fibers of the second fiber composition to a Shopper-Leighler number of more than 40, preferably more than 70; supplying the first fiber composition in foam form to a mold and molding the first fiber composition in the mold to prepare a first foamed fiber layer; and supplying the second fiber composition in foam form to a mold and molding the second fiber composition in the mold to prepare a second foamed fiber layer to obtain 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, and the supply steps may be performed in any order. The supply to the mold involves supplying the fibrous composition in foam form to the internal space / volume of the mold, which is limited by the inner surface of the mold. • The supply to the mold includes supplying the fibrous composition in foam form into the closed cavity of the mold. The molding process involves pressing the fiber composition within the internal space of the mold by bringing parts of the mold closer together.

[0015] According to a fifth aspect of the present invention, there is a molded multilayer fiber product that is oven-safe, comprising a first fiber layer containing a cellulose fiber material, and a second fiber layer located above the first fiber layer, the second fiber layer containing a cellulose fiber material, wherein the first and / or second fiber layers exhibit barrier properties substantially throughout their structure, and the product is configured to heat food or liquids placed on it to preferably at least 100°C, preferably 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-fiber release layer on top of the second fiber layer, which forms the top layer of the product when in use, and the non-fiber release layer is configured to come into direct contact with food or liquids and to facilitate the release of food or liquids from the product after being heated over them. The non-fiber release layer contains a silicone composition. The dry basis weight of the non-fiber peel-off layer is 2.0 g / m². 2 Less than 0.5-2.5 g / m 2 That is the case. The first fiber layer forms the bottom fiber layer of the product during use, and the second fiber layer forms the top fiber layer of the product during 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 fiber layers are substantially oil-resistant and grease-resistant throughout their entire structure. The first and / or second fiber layers are water-resistant and / or water vapor-resistant substantially throughout their structure. The product further includes one or more inner fiber layers between the first fiber layer and the second fiber layer, each containing cellulose fiber material. The second fiber layer forms the top fiber layer of the product and has higher oil and grease resistance than the fiber layer below it. The first fiber layer forms the bottom fiber layer of the product and has higher water resistance and / or higher water vapor resistance than the fiber layers above it. The cellulose fiber material of the product's fiber layer comprises or consists of bleached chemical wood pulp, preferably bleached softwood chemical wood pulp and / or bleached hardwood chemical wood pulp. The cellulose fiber material of the first and / or second fiber layers comprises cellulose fibers refined to a Shopper-Leighler number of 40 or more, such as 70 or 80, preferably softwood chemical pulp. • The number of shopper layers in the bottom fiber layer and / or one or more inner fiber layers of the product is less than 50, such as less than 30, less than 40, etc. 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 is 600-950 kg / m³, calculated as dry solid weight per unit volume. 3 , 800 kg / m 3 Ultra-high, etc., 300-1000 kg / m 3 It is within the range. • The density of the bottom fiber layer and / or one or more inner fiber layers of the product is 500 kg / m³. 3 Less than 600 kg / m 3 It is less than. At least one of the fiber layers, preferably at least two fiber layers, contains one or more additives, such as pigments, barrier agents, binders, and sizing agents such as AKD. At least one, preferably at least two, fiber layers contain MFC and starch. • Products are, for example, 100-900g / m² 2 range, 300-600g / m 2 Ranges such as 200-400g / m 2 For example, within the range of 5-900g / m². 2 It has a dry basis weight within the range of [specify range]. • The top and / or bottom fiber layers of the product should be 30-50 g / m². 2 Ranges such as 20-80g / m 2 It has a dry basis weight. • The top and / or bottom fiber layers of the product should be 50-150 g / m². 2 It has a dry basis weight within the range of [specify range]. The product is a three-dimensional molded multilayer fiber product obtained by using a mold that includes 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, wherein the product is preferably obtained by a foam molding method or a water molding method within the mold. This product is a baking or cooking container such as a food or liquid packaging, container, or tray, or an oven-safe pot, that is oven-safe or microwave-safe for food or liquids.

[0017] According to a sixth aspect of the present invention, the use of an oven-safe molded multilayer fiber product according to the fifth aspect is provided in baking, cooking, and / or heating food or liquids.

[0018] A molded multilayer fiber product is provided, obtained by a method comprising the steps of forming a molded multilayer foamed fiber structure from at least one foamed fiber composition comprising cellulose fibers, water, air, and a foaming agent; dehydrating the structure, preferably by applying a vacuum; and hot pressing the dehydrated structure to obtain a molded multilayer fiber product, wherein at least one of the fiber layers of the foamed molded multilayer fiber 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 multilayer foamed fiber structure includes the steps of: providing a first fiber composition; providing a second fiber composition, which includes purifying the cellulose fibers of the second fiber composition to a Shopper-Leighler number of more than 40, preferably more than 70; supplying the first fiber composition in foam form to a mold and molding the first fiber composition in the mold to prepare a first foamed fiber layer; and supplying the second fiber composition in foam form to a mold and molding the second fiber composition in the mold to prepare a second foamed fiber layer to obtain a two-layer molded foamed fiber structure. The first foam fiber layer is located either above or below the second foam fiber layer in the mold, and the supply step can be performed in any order. The hot press includes two or more consecutive hot press steps. The total duration of the hot press is less than 30 seconds, such as less than 20 seconds.

[0020] (Advantages of the present invention)

[0021] This invention avoids the need for a separate non-fiber barrier coating layer and avoids problems related to coating adhesion.

[0022] This invention may enable the rapid production of multilayer molded fiber products. Cycle times can be shortened. Wetting or re-wetting of the product by a separate coating step can be avoided.

[0023] This invention may make it possible to easily adjust the characteristics of individual layers.

[0024] The present invention may make it possible to obtain lightweight, bulky, and homogeneous multilayer fiber molded articles. Because the product is lightweight, logistics and transportation costs can be reduced.

[0025] This invention avoids separate conversion steps and conversion logistics.

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

[0027] In this invention, fiber aggregation and a cloudy appearance can be avoided or mitigated.

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

[0029] The present invention may provide oven-safe and / or micro-oven-safe, biodegradable, compostable, and recyclable multilayer molded fiber products.

[0030] This invention can reduce energy consumption, particularly when using foam molding, because it reduces the need for dehydration and drying of the product.

[0031] This invention can reduce production costs associated with cycle time, dehydration, drying, and chemicals. Chemical retention can be improved, especially when using foam molding.

[0032] The present invention can provide a textile product having good barrier properties.

[0033] The present invention may provide textile products with complex shapes that are free from wrinkles and cracks.

[0034] This invention may provide plastic-free textile packaging that can be recycled using existing textile recycling infrastructure.

[0035] This invention may enable the replacement of existing, often plastic-based, packaging solutions. [Brief explanation of the drawing]

[0036] [Figure 1] This figure schematically illustrates a multilayer fiber product according to at least some embodiments of the present invention. [Modes for carrying out the invention]

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

[0038] In this context, "resistance," such as water resistance, means that the material or layer resists the penetration of the substance in question. In a preferred embodiment, the material or layer exhibits "repellency," such as water repellency, which means that the substance in question cannot easily penetrate the material or layer. In a more preferred embodiment, the material or layer exhibits "prevention," such as waterproofing, which means that the substance cannot penetrate the material or layer during normal use of the product containing the material or layer. In other words, resistance to the penetration of the substance in question increases in the order of "resistance" < "repellency" < "prevention."

[0039] Furthermore, in this context, the term "resistance" means "at least resistant." In other words, the material or layer may exhibit water repellency, and even waterproofing.

[0040] In this context, the expression "a layer exhibits barrier properties" usually means that the layer is configured, such as by being modified or adjusted, to have increased resistance to the penetration and / or movement of a particular (predetermined) substance or group of substances. Therefore, such a layer exhibiting barrier properties is configured to form a barrier against the penetration and / or movement of the said substance.

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

[0042] In this specification, the term “hot pressing” typically refers to a method of increasing pressure and temperature over a period of time. Hot pressing may include several consecutive cycles or steps of increasing pressure and temperature. In some cases, hot pressing may also include applying a pressure below atmospheric pressure.

[0043] In this specification, the term “molded product” means a product obtained by molding or shaping a product within a closed or closable cavity of a mold. Typically, “molding” does not refer to simply pressing a product between two plates.

[0044] In this specification, the term “oven-safe product” typically refers to a product that is configured to be heated in an oven when holding or transporting food or liquids that will be consumed by humans or animals.

[0045] In this context, the term "food" usually refers to food intended for consumption by humans or animals.

[0046] In this specification, the term “liquid” usually refers to a liquid or fluid material intended for human or animal consumption, such as a beverage.

[0047] The present invention provides a novel molded fiber product having improved barrier properties. At least a portion of the product can be manufactured by a foam-based process. Foam molding advantageously allows for the preparation of molded multilayer structures and the adjustment of the properties of individual layers.

[0048] The product is typically a three-dimensional molded multilayer product obtained using a foam molding process.

[0049] Preferably, at least one of the fibrous layers prepared by foam molding exhibits improved barrier properties. This at least one of the fibrous layers can function as a barrier against oil, grease, fat, water, water vapor, liquids, fragrances, gases and / or oxygen.

[0050] According to the present invention, the product is a molded multilayer fiber product comprising a first fiber layer containing cellulose fiber material, and a second fiber layer located above the first fiber layer, the second fiber layer containing cellulose fiber material, wherein the first and / or second fiber layers exhibit barrier properties substantially throughout their structure. In a preferred embodiment, the product is configured to heat food or liquids placed on it to at least 100°C, preferably at least 220°C.

[0051] Cellulose fiber materials may include wood pulp selected from the group consisting of chemical pulp, mechanical pulp, and any combination thereof.

[0052] Cellulose fiber materials may include one or more of the following: chemical wood pulp, mechanical wood pulp such as chemothermetic pulp, fibrillated cellulose such as microfibrillated cellulose and nanocellulose, and any other cellulose materials containing cellulose fibers or parts of cellulose fibers.

[0053] Cellulose fiber materials may also include non-wood pulps such as straw pulp.

[0054] In some embodiments, the cellulose fiber material includes or substantially consists of virgin wood pulp, such as virgin bleached chemical pulp that is substantially lignin-free, thereby making the product particularly suitable for cooking, heating, and contact with food, such as in a micro oven.

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

[0056] The advantage of virgin pulp is that it does not contain pigments and other undesirable chemicals. Recycled waste often contains chemical and microbial contaminants that can affect safe use. Mixtures of chemical compounds and microbial products can leach from recycled materials and have various adverse effects on health or the environment. The toxicity of recycled materials and their emissions can increase not only due to the toxicity of individual compounds but also due to interactions with other compounds and microbial products. Therefore, it is preferable in this invention to avoid using recycled materials.

[0057] The advantage of chemical pulps, such as bleached chemical pulp, is that they are virtually lignin-free. A further advantage of chemical pulps is that the interfiber bonding in the final product may be better than that of mechanical pulps.

[0058] Lignin-containing pulp often possesses sensory properties that are insufficient for direct contact with food. Furthermore, lignin-containing pulp is sensitive to aging and yellowing of the material.

[0059] In one embodiment, the cellulose fiber material of the second fiber layer includes 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 cellulose fiber material of the second fiber layer contains 50-95 wt% bleached coniferous chemical pulp.

[0061] In one embodiment, the cellulose fiber material of the second fiber layer contains 5 to 50 wt% bleached hardwood chemical pulp.

[0062] In one embodiment, the cellulose fiber material of the second fiber layer includes or consists of bleached coniferous chemical pulp.

[0063] In one embodiment, the cellulose fiber material of the second fiber layer includes or consists of bleached hardwood chemical pulp.

[0064] Barrier properties may include one or more of the following: 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 demonstrated by the top fiber layer.

[0066] Preferably, barrier properties such as oil resistance and / or grease resistance of the fiber layer are obtained by mechanical treatment of the fibers. The mechanical treatment may be treatment of the fibers in the finished pulp, and this treatment is configured to increase the density of the formed layer, such as a treatment that increases the Schöpper-Liegler number of the fibers. The Schöpper-Liegler value can be obtained by the standard method EN ISO 5267-1.

[0067] In one embodiment, barrier properties are provided to the fiber layer by incorporating mechanically processed cellulose and / or lignocellulose fibers, such as mechanically manufactured MFCs (microfibrillated cellulose), NFCs (nanofibrillated cellulose), or glue pulp.

[0068] The first fiber layer may form the bottom fiber layer of the product during use, and the second fiber layer may form the top fiber layer of the product during 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 and is 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, the bottom fibrous layer may be located above one or more non-fibrous layers, forming the bottom layer of the product.

[0071] If the product is a container, holder, or support structure, the second fiber layer may be configured to come into direct contact with the contents of the container, holder, or support structure.

[0072] The second fiber layer may be configured to be in direct contact with food, liquid, or beverage, or at least to form a fiber layer closest to the food, liquid, or beverage. Food, beverages, and liquids often contain oils, fats, and / or water, and it is necessary to avoid penetration of these into the fiber layer of the product.

[0073] Preferably, the first and / or second fiber layers, particularly the second fiber layer, are substantially oil-resistant and grease-resistant throughout their entire structure. Alternatively, the first and / or second fiber layers, particularly the second fiber layer, are substantially water-resistant throughout their entire structure.

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

[0075] In one embodiment, the moisture permeability of the product or fiber layer is measured according to ISO 2528 and ASTM E96 under standard conditions of 23°C and 50%RH and is at a level of "moderate" or lower.

[0076] In one embodiment, the water absorption on the barrier side of the product is measured by the ISO 535 Cobb value after 3 minutes and is at a level of "moderate" or lower.

[0077] The first fiber layer may be configured to be in direct contact with the outer surface on which the product is placed.

[0078] Typically, the first fiber layer forms the bottom fiber layer of the product and has lower oil and grease resistance than the second fiber layer. The bottom fiber layer of the product is usually not configured to come into direct contact with oily substances such as food.

[0079] In one embodiment, the bottom fiber 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.

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

[0081] In one embodiment, the product comprises three fiber layers, namely first and second fiber layers and a single inner fiber layer between them.

[0082] In one embodiment, the product is oven-safe. Preferably, the product contains mechanical pulp such as BCTMP or one or more inner layers made of mechanical pulp.

[0083] The top fiber layer and / or bottom fiber layer may contain bleached chemical pulp.

[0084] One or more inner fiber layers may contain mechanical pulp.

[0085] The barrier properties of a product, particularly its fiber layer, can be enhanced in various ways.

[0086] In one example, the purification of fiber starting materials is used to increase the density of the final product and obtain barrier properties for the desired layer.

[0087] The top fiber layer may consist of 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 cellulose fiber material of the second fiber layer may contain cellulose fibers refined to a Shopper-Leighler number greater than 40, such as greater than 60, for example, greater than 70, greater than 80, etc.

[0089] The cellulose fiber material in the bottom fiber layer and / or inner fiber layer may contain unrefined cellulose fibers or cellulose fibers that are less refined than the refined cellulose fibers in the top fiber layer.

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

[0091] For example, the number of shopper layers in the bottom fiber layer and / or one or more inner fiber layers of a product can range from 10 to 50.

[0092] For example, the Shopper Leaguer count for the top fiber layer could be over 40, such as over 50.

[0093] For example, the number of shopper-leads in the bottom fiber layer can be more than 10, such as more than 15.

[0094] In one embodiment, the density of each fiber layer is 100 kg / m³. 3 Larger.

[0095] In some embodiments, the density of the second fiber layer is greater than the density of the first fiber layer. In one embodiment, the density of the second fiber layer is 100 kg / m³. 3 Larger. Preferably, the density of the second fiber layer is calculated as dry solid weight per unit volume, and is 500-950 kg / m³. 3For example, 600 kg / m 3 Ultra-high, etc., 300-1000 kg / m 3 It is within the range.

[0096] Preferably, the density of the first fiber layer is 400 kg / m³ 3 Less than, for example, 300 kg / m 3 Less than 500 kg / m 3 It is less than 800 kg / m³, and the density of the second fiber layer is 800 kg / m³. 3 Super, etc., 500 kg / m 3 It's incredible.

[0097] The density of the second fiber layer can be substantially uniform throughout its entire structure.

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

[0099] Both purification and the addition of barrier agents can be used to achieve barrier properties, particularly in one or more fiber layers.

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

[0101] The additive or chemical is preferably added to the fibrous finished paper stock or slush at a viscosity of, for example, 0.5 to 15% or 2 to 10% before the foam molding step, or added to the foam mixed with the fibrous slush having the viscosity before foam molding.

[0102] It is preferable that additives or chemical substances be added to the fibrous finished paper stock or slush at a viscosity of less than 5%, for example, less than 2%.

[0103] At least one of the fiber layers, such as the first and / or second fiber layer, may contain one or more additives, including talc, clay, pigments such as heavy calcium carbonate, barrier agents, latex binders, water-soluble binders such as PVA, starch, and CMC, and sizing agents such as AKD.

[0104] The amount of additive can be calculated from the total dry weight of the fiber layer and may range from 0.01 to 30 wt%, such as 0.01 to 10 wt%, 0.1 to 8 wt%, or 1 to 5 wt%.

[0105] In one embodiment, at least one of the fiber layers, such as a second fiber layer, contains 0.1 to 5 wt% talc.

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

[0107] In one embodiment, at least one of the fiber layers, such as a second fiber layer, contains 0.1 to 5 wt% calcium carbonate.

[0108] In one embodiment, at least one of the fiber layers, such as a first and / or second fiber layer, comprises a barrier agent selected from the group consisting 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 fiber layers, such as a first and / or second fiber layer, contains a barrier agent, such as a dispersed polymer barrier agent, in an amount of 0.1 to 15 wt%, such as 0.1 to 10 wt%, 0.1 to 5 wt%, etc. Such a barrier agent typically provides the barrier properties throughout the entire structure of the fiber layer, especially without purification.

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

[0111] In one embodiment, at least one of the fiber layers, such as a second fiber layer, contains 0.1 to 15 wt% of polyvinyl alcohol (PVA), such as 0.1 to 5 wt%.

[0112] In one embodiment, at least one of the fiber layers, such as a second fiber layer, contains 0.1 to 20 wt% of starch, such as 0.1 to 5 wt%.

[0113] Starch can be natural, modified, cooked, or swollen cationic starch.

[0114] In one embodiment, one of the fiber layers, such as a second fiber layer, contains 0.1 to 5 wt% CMC.

[0115] In one embodiment, at least one of the fiber layers, such as a second fiber layer, contains 0.1 to 20 wt% of an inorganic filler.

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

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

[0118] Preferably, the fiber layer of the product contains less than 5 wt% of wax, plastic, and fluorochemicals, such as less than 2 wt%. In one embodiment, the fiber layer of the product contains less than 2 wt% of wax. In one embodiment, the fiber layer of the product contains less than 2 wt% of plastic, such as less than 1 wt%. In one embodiment, the fiber layer of the product contains less than 2 wt% of fluorochemicals, such as less than 1 wt%. In some embodiments, the product is substantially free of wax, plastic, and fluorochemicals, particularly plastics.

[0119] For oven-safe applications, additives and foaming chemicals may be selected from additives approved for use in materials or packaging that come into contact with food and are further approved for oven-safe food packaging intended for heating. Preferably, additives are selected from those approved in BfR XXXVI / 2 “Paper and cardboard for baking”: https: / / bfr.ble.de / kse / faces / resources / pdf / 362-english.pdf.

[0120] For products not intended for oven use, additives and foaming chemicals can be selected more freely from among all additives approved for use in materials or packaging that come into contact with food. Additives may include water-based barrier additives.

[0121] The amount of barrier additive can range from 1 to 15 wt%, such as 1 to 10 wt%, 5 to 8 wt%, etc., calculated from the total dry weight of the fiber layer.

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

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

[0124] In one embodiment, the first fiber layer and / or the second fiber layer include a sizing agent such as a modified rosin, wax, oil, or polymer. The advantage of using a sizing agent is that it can reduce the undesirable absorption of liquids and / or water and / or moisture into the foamed molded structure. This improves the moisture resistance 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 polymer sizing agent is styrene acrylate emulsion (SAE).

[0126] The 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 sizing agents. In addition to these, or as alternatives, several reactive sizing agents, such as alkyl ketene dimers (AKDs), may be used as surface sizing agents.

[0128] Suitable cationic sizing agents include cationic starches and starch derivatives, as well as corresponding carbohydrate-based natural polymers. Among 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 corresponding carbohydrate-based natural polymers such as carboxymethylcellulose and its salts, and alkylcelluloses such as methylcellulose and ethylcellulose. Synthetic polymers include styrene / maleic acid copolymer (SMA), diisobutylene / maleic anhydride, styrene acrylate copolymer, acrylonitrile / acrylate copolymer, polyurethanes containing the same chemical functional groups, and similar latex products.

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

[0131] In one embodiment, additives such as pigments, binders, and sizing agents are adapted for oven-safe products.

[0132] In some embodiments, the product is, for example, 100-900 g / m². 2 For example, a range of 200-400 g / m 2 Or 400-600g / m 2 Ranges such as 5-900g / m 2 It has a dry basis weight within the range of [specify range].

[0133] In one embodiment, the bottom fiber layer and / or inner fiber layer of the product is 100-400 g / m². 2 For example, 230-270 g / m 2 such as 80-400g / m 2 It has a dry basis weight within the range of [specify range].

[0134] In one embodiment, the bottom fiber layer and the top fiber layer of the product each have a density of 80-150 g / m². 2 It has a dry basis weight within the range of [specify range].

[0135] In one embodiment, the inner fiber layer of the product is 150-250 g / m². 2 It has a dry basis weight within the range of [specify range].

[0136] In one embodiment, the density of the inner fiber layer is 100 kg / m³. 3 Larger.

[0137] In one embodiment, the second fiber layer of the product is, for example, 60-150 g / m². 2 , or for example, 20-60 g / m 2 For example, 30-50 g / m 2 such as 10-150g / m 2 It has a dry basis weight within the range of [specify range].

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

[0139] In some embodiments, the molded multilayer fiber product further includes a release layer as the top layer of the product. The release layer is advantageous in baking applications, for example, in bread pans. Furthermore, the presence of the release layer can protect the fibers of the first and second fiber layers from heat.

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

[0141] Typically, a non-fiber release layer is configured to facilitate the release of food or liquid from a product such as a container after it has been in direct contact with the food or liquid and heated in 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 fiber layer. The intermediate layer may include or consist of PVA, CMC, starch, or a combination thereof.

[0143] The advantage of using an intermediate layer between the release layer and the fiber layer is that it can avoid mixing of the release layer material with the fiber structure.

[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 may include a silicone composition, such as a sprayable silicone composition. The silicone composition may include an emulsion or a solvent-free system.

[0146] The silicone composition may include a cured modified silicone having very low surface tension and good isolation effect. The modified silicone component can be crosslinked with a platinum catalyst. The product obtains high temperature resistance.

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

[0148] The dry basis weight of the peeled layer is 2.0 g / m². 2 Less than 0.5-2.5 g / m 2 It could be within the range of.

[0149] Figure 1 schematically shows a multilayer fiber product according to at least some embodiments of the present invention. This product includes a first fiber layer 1 which is the bottom fiber layer, a second fiber layer 2 which is the top fiber layer, and an inner fiber layer 3 between the first fiber layer 1 and the second fiber layer 2. Furthermore, the product includes a non-fiber release layer 5 which is the top layer of the product, and an intermediate layer 4 between the non-fiber release layer 5 and the top fiber layer 2 of the product. One or more of the fiber layers 1, 2, and 3 may exhibit barrier properties.

[0150] In another embodiment, the product comprises only one fiber layer, such as a first fiber layer 1, a non-fiber 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 fiber layer. In other embodiments, the product includes one, two, or three inner fiber layers between the first fiber layer 1 and the second fiber layer 2.

[0153] It is preferable that multilayer products are obtained such that all fibers included in the final structure are subjected to the foam molding process. In some embodiments, all fibers included in the layer exhibiting barrier properties are subjected to the foam molding process.

[0154] For example, a fiber layer exhibiting at least barrier properties can be obtained by a foam molding method within a mold. Such a fiber barrier layer may be any fiber layer, such as an outermost fiber layer, a bottommost fiber layer, and / or one or more inner fiber layers.

[0155] The advantages of foam molding are that it allows for the production of lighter and bulkier products. Furthermore, it enables the achievement of more homogeneous molding. By using foam, multilayer structures can be easily manufactured in a batch process. That is, all layers can be formed in the same mold to form a multilayer stack within the mold, and that stack can then be hot-pressed.

[0156] The advantage of dewatering the entire multilayer structure within the same mold is that, compared to dewatering each layer individually, the bonds between layers may be strengthened during the dewatering process.

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

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

[0159] Preferably, the product is a three-dimensional molded multilayer fiber product obtained by using a mold that includes at least one three-dimensional non-planar mold surface, the product exhibiting a three-dimensional shape that matches the shape of the three-dimensional non-planar mold surface.

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

[0161] Typically, the products are food or liquid packaging or containers, or food or liquid serving products such as beverage cups, food trays or plates, baking pans, or disposable lasagna tray molds.

[0162] In some embodiments, the product is oven-safe, for example, 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 packaging or container, such as a food tray.

[0164] One example is a baking container, such as an oven-safe pot.

[0165] This product can be used for packaging, storing, serving, cooking, and / or heating food, liquids, and beverages.

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

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

[0168] Below are examples of multilayer product structures suitable for specific applications.

[0169] In one example, the top fiber layer of a product is a barrier layer, such as a water-resistant barrier layer. The product could be fruit packaging. The barrier function is to prevent the packaging from getting wet and the resulting deterioration of its appearance.

[0170] In one example, the top fiber layer of a product is a barrier layer, such as an oil-resistant and grease-resistant barrier layer. The product may be packaging for oily foods. The barrier function is to prevent oil and grease from penetrating into the packaging during transport or heating.

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

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

[0173] Molded multilayer fiber products can be used as packaging for food or liquids, as serving products for food or liquids, or as part of baking products.

[0174] One embodiment provides a product obtained by the following method.

[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 slush containing fibers; purifying the fibers of the fiber slush and / or adding a barrier agent to the fiber slush; preparing the fiber slush into a foamed composition; forming the foamed composition in a mold, such as molding and pressing; dewatering; and hot pressing.

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

[0177] This method first provides a foamed composition comprising fibers, water, air, and one or more foaming chemicals. The foam may further contain fillers, additives, pigments, binders, barrier dispersants, and sizing agents.

[0178] The foaming chemicals used, such as surfactants, can be nonionic, anionic, cationic, or amphoteric. The appropriate amount of surfactant is approximately 150–1000 ppm by weight. Examples of anionic surfactants include alpha-olefin sulfonates, while an example of a nonionic surfactant is PEG-6 lauramide. A specific example is sodium dodecyl sulfate.

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

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

[0181] Fibers may include all kinds of fibers from chemical and / or mechanical pulp, regenerated fibers, crushed fibers, agricultural waste flow, annual plant fibers, by-products, micro or nanofibrillated cellulose fibers and regenerated cellulose fibers, as well as combinations thereof.

[0182] In one embodiment, a molded multilayer fiber product is obtained by a method comprising the steps of: forming a molded multilayer foam structure from at least one foam fiber composition comprising cellulose fibers, water, air, and a foaming agent, and optionally a barrier agent; dehydrating the structure, preferably by applying a vacuum; and hot pressing the dehydrated structure to obtain a molded multilayer fiber product. At least one of the fiber layers of the multilayer fiber product exhibits barrier properties substantially throughout its structure.

[0183] In this specification, "forming," and usually "foam molding," refers to the process of giving a foam composition a shape, such as a three-dimensional shape, within a mold.

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

[0185] A foamed composition can be supplied to a mold to provide a certain amount of the foamed composition, for example, a layer of the foamed composition, on at least one inner surface of the mold. This layer is typically non-planar and exists on the inner surface of the mold, and can be understood as a thickness of the foamed composition that conforms to the shape of the surface, for example, a substantially constant thickness.

[0186] Typically, the molding step involves pressurizing the fiber composition within the internal space of the mold by bringing parts of the mold closer together.

[0187] The step of forming a multilayer foamed structure may include supplying a first fibrous composition in foam form to a mold and molding the first fibrous composition in the mold to prepare a first foamed fibrous layer. The process is then continued by supplying a second fibrous composition in foam form to the mold without removing the first fibrous layer from the mold, and molding the second fibrous composition in the mold to prepare a second foamed fibrous layer. As a result, a two-layer foamed structure is obtained in the mold.

[0188] Unless otherwise specified, "mold portion" refers to the portion of the mold that defines the internal space and therefore contributes to the molding of the foamed fiber composition.

[0189] The second foam fiber layer may be supplied and placed above or below the first foam fiber layer in the mold. The supply step may also be performed in either order, and either the first or second layer may be formed in the mold first.

[0190] The product may be obtained by using separate molds to prepare the first and second foamed fiber layers, and the obtained first and second fiber layers may be joined together in the hot-press step.

[0191] In one embodiment, the supply to the mold includes supplying a foamed fiber composition in foam form into the internal space or internal volume of the mold, the internal space being limited by the inner surface of the mold.

[0192] It is preferable that a vacuum be applied during the dehydration step.

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

[0194] It is preferable that the distance between each part of the mold can be adjusted during the supply and molding of the foam composition.

[0195] Before supplying a second fiber composition or the like into the mold, it is usually necessary to move the mold components apart from each other to expand the internal space of the mold. The volume of the internal space can be reduced or increased to mold the already supplied foam and to create space for the foam to be supplied next.

[0196] When adjusting the entire internal volume of a mold, some parts of the mold may remain stationary while others move.

[0197] In one example, during the approach or enlargement, one or more parts of the mold remain stationary, while one or more other parts of the mold move.

[0198] For example, a mold may comprise two sub-molds, such as two half-molds, positioned facing each other and movable relative to one another. The sub-molds can be brought close together to mold a product. The sub-molds can be moved apart to enlarge the internal space, or they can be moved further apart to open the molds and remove the molded product from them.

[0199] In one example, a product may be obtained by using a mold comprising two parts, namely a negative mold and a positive mold. These molds may be positioned facing each other so as to enclose an internal space between the two parts, also called a molding space or molding cavity. The composition to be molded or formed is fed into the molding space, and the negative mold and / or 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 of reducing the internal space by moving one or both of the positive and negative molds.

[0200] Dehydration of the structure can be performed by applying a vacuum to the internal space of the mold containing the supplied foam composition.

[0201] The dehydration step is performed before the hot pressing step, which yields the final, usually dry, product in which all layers are bonded together. In the hot pressing step, the temperature is typically higher than room temperature, for example, at least 50°C, for example at least 100°C, for example at least 150-240°C.

[0202] A hot press may involve two consecutive hot press steps.

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

[0204] For example, a hot press may include two hot press steps in which heat is applied from both sides. Alternatively, a hot press may include two hot press steps in which heat is applied from different sides.

[0205] Hot pressing can contribute to the development of barrier properties through chemical reactions that occur at high temperatures, such as crosslinking and curing reactions. Therefore, hot pressing may be advantageous when using barrier chemicals such as AKD. [Examples]

[0206] (Examples)

[0207] The following describes an embodiment in which a product is obtained using a mold consisting of two parts called a pair of molds.

[0208] Any of the features and combinations of features described below can be combined with the embodiments and alternative forms described in this application.

[0209] This method is for forming fibrous molded articles. In this method, layers are formed from foam. The layers are part of the final product. The foam, also called a “foamed composition,” contains fibers, water, air, and one or more foaming chemicals. The foam may also contain fillers and other common papermaking chemicals such as additives, pigments, colorants, and binders.

[0210] Fibers may include all kinds of cellulose and / or lignocellulose fibers from chemical pulp and / or mechanical pulp, recycled fibers, crushed fibers, by-products, micro- or nanofibrillated cellulose and regenerated fibers, as well as combinations thereof.

[0211] A single foam layer recipe can consist of a freely selected mixture of the aforementioned raw materials. Naturally, the recipes for different layers can differ from one another.

[0212] This layer is formed by a pair of molds. Each mold may consist of multiple sub-molds for a single product.

[0213] As a general rule, one mold is a negative mold and the other is a corresponding positive mold. In this way, a three-dimensional shape is obtained during layer formation. Water and air in the foam must be removed. This is mainly done by reducing the distance between the molds and applying pressure. The pressure pushes the air and water out of the foam supplied between the molds. The porous surface of the mold (product surface) provides a pathway for the water and air to escape, with fibers forming a residual layer.

[0214] The foam can be supplied through one of the molds. The molds are spaced apart from each other and have closed cavities for the foam. This allows for faster foam supply and greater flexibility in timing.

[0215] The foam can be supplied through both molds.

[0216] In this example, the pair is formed from an upper mold and a lower mold, with the upper mold being movable and the lower mold being fixed. The foam is supplied through the lower mold.

[0217] The foam can be supplied when the pairs are separated from each other or when the pairs are moving relative to each other. This shortens the molding cycle. For example, the foam can be supplied even while the upper mold is rising. On the other hand, the pairs may be moved away from each other first, and only then may the supply of foam begin.

[0218] Further advantages are gained by passing the foam through a mold. It becomes possible to form not only single layers, but also multiple layers through a lamination process. The formed layers can be removed from the inside of the pair after formation. Alternatively, after the layers are formed, the pairs can be separated from each other, more foam can be supplied for further layers, and then the pairs can be brought together again. Here again, the foam can be supplied while the pairs are separated from each other.

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

[0220] The next step is hot pressing to remove water bound to the fibers. During the hot pressing stage, the layers finally bond together. Furthermore, high temperatures can cause barrier properties to develop and / or manifest.

[0221] Surprisingly, after the first layer, further layers can be formed on either side of the textile product. In other words, the foam may be supplied to either side of the preceding layer. For example, one inner layer may be formed first to function as the main layer, and then another layer may be formed on either side of the inner layer to function as the surface layer. Thus, a total of three layers may be present.

[0222] Multilayer products can also be manufactured by other methods. A product can be assembled by combining multilayer sub-products obtained from two separate pairs of molds. These sub-products formed from the two pairs can be combined, hot-pressed, and a single product can be obtained. 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. Combining these layers results in a four-layer product.

[0223] The ability to rapidly form multiple layers to constitute a single product is a significant 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 a single product. Thus, each layer can be different from the others. A product may, for example, contain one or two inner layers formed from one type of foam. In that case, there may be at least one outer layer of a different type of foam. Therefore, the cross-sectional shape of the product can vary depending on the foam.

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

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

[0226] At such low temperatures, the fibers of the product retain moisture. During hot pressing, the moisture is released as water and steam, which also provides a smooth surface and contributes to internal bonding to form a solid, layered product. Furthermore, barrier properties may develop and / or manifest at the high temperatures applied during hot pressing.

[0227] As soon as the pairs begin to separate, the foam is supplied to the internal space of the mold. When the pairs move closer together again, the supply stops and water is discharged from the pairs. At the same time, air is also removed.

[0228] The removal of water and air by pressing may be facilitated by a vacuum.

[0229] While this method can be used to form single-layer products, it is more advantageous when forming multi-layer products.

[0230] Foams are made from water, air, fibers, and foaming chemicals. Foams contain small pieces or particles of the fibers in question. Foaming chemicals are also used to promote foam formation and maintain the foam's shape.

[0231] Fibers can vary greatly in their origin and composition. For example, wood fibers or plant fibers (e.g., straw, bagasse, and bamboo fibers) can be used, but artificial cellulose fibers are also possible.

[0232] In a proper foam, water, fibers, and additives are uniformly dispersed within the foam's cell walls. The foam is a non-cohesive, heterogeneous fiber material, where the air within the foam carries the fibers and other materials into the formation process. Using a foam also results in very high fiber retention. In fact, over 99% of the fibers remain in the product formed from the thick foam acting as the carrier medium.

[0233] Additives may have different retention properties depending on the purpose. Retention aids may be added.

[0234] By forming textile products with multiple layers, the properties of the product can be adjusted in various ways. For example, the basic structure and surface properties of a product may be formed with different foam compositions. In practice, each layer may have its own process parameters and raw materials. For example, the rigid body of the product may be formed with inexpensive fibers, while the surface layer may be formed with high-quality fibers. Compared to known processes using aqueous fiber slurry, foams have a much higher fiber density. At the same time, the amount of water in the circulating bubble walls is also significantly reduced, making it easier to remove water during formation. Foams with less water enable faster process cycles.

[0235] It may be possible to change the proportion or type of foam in different layers of the product.

[0236] Especially when a vacuum is used, the foam can be supplied into the mold space quite quickly.

[0237] In a suitable foam, the air bubbles do not separate, and the fibers are uniformly dispersed. During formation, the foam is distributed or supplied to the internal space between two molds. The volume of the internal space can be adjusted according to the required layer thickness.

[0238] For example, the formation of the next layer can occur on either side of the preceding layer. Also, the supply of foam may have already begun while the pairs are separated. This is advantageous because, during separation, air cannot enter the space in front of the foam, and the mold space is immediately filled with foam.

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

[0240] Vacuum can also be used. Vacuum is useful for removing water and air. Vacuum can be applied even while the foam is being supplied, or at the latest when the pairs begin to approach each other. During formation, the mold space decreases, but not as much as during the actual pressing steps after formation. Furthermore, it is possible to hold the formed layer under vacuum on the desired mold surface (inner surface) and form an additional layer on a selected side of the previous layer.

[0241] To control the optimal foam structure for uniform product formation, forming can be performed without heating. In practice, forming is carried out at a substantially constant process temperature, preferably 15-45°C. In addition to a pair of molds, this temperature can be maintained throughout the entire foaming system, ensuring the optimal bubble size for high product quality. In this way, the lifespan of the foam can be extended. Furthermore, air is easier to remove than with steam, the layers are not damaged, and the process is stable. In practice, the foam contains more than 50% air, preferably 55-75% air.

[0242] The optimal bubble size for the foam during formation is approximately 10 to 500 μm in diameter, preferably 50 to 150 μm in diameter.

[0243] Remarkably, the foaming process of the present invention simultaneously achieves high viscosity and good formation compared to known aqueous slurry formation processes. These water-based processes require longer heating and dewatering times because they have much lower viscosity and insufficient formation due to aggregation.

[0244] Laminated products are formed as layers on top of each other, and pressing and dewatering are ultimately carried out through the mold and the preceding layer below. The layered structure is joined by hot pressing at the latest.

[0245] Laminated products can be formed in any order as needed. In other words, formation may begin with any of the inner layers or any of the outer layers.

[0246] The bonding between layers is ensured by dehydration through the layer interfaces.

[0247] The bonding of the layers continues in the subsequent hot-pressing step, and the heat and steam generated within the product, as well as the steam passing through the layers, further strengthen the bonds between the layers. During the hot-pressing step, the barrier chemicals may be distributed more and / or more uniformly within one or more fiber layers.

[0248] Lamination can be performed using the same fiber, but different additives may be used for different layers.

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

[0250] Following the hot-pressing step, an optional additional drying step at high temperature may follow to cure additive chemicals such as barrier agents, as in AKD. Such additional drying is also advantageous if the product contains a non-fiber release layer (typically including silicone).

[0251] This method involves generating a foam from fibers, water, air, and foaming chemicals. As mentioned earlier, the properties of the foam can vary. Furthermore, this method involves using a pair of molds whose distance from each other varies. In other words, the distance between the molds, i.e., the volume of the internal cavity, can vary. In practice, after supplying the foam, the molds are pressed together to remove water and air, thereby forming the product.

[0252] Furthermore, this method further includes supplying foam between molds to form layers. A single layer may constitute the product, but advantageously, the product may contain multiple layers. The foam can be supplied even when the molds are separated from each other, and also when the pair of molds are moved relative to each other. This shortens the process cycle and increases the options for coordinating the process and the product.

[0253] This method may comprise creating a closed mold space and supplying a large amount of foam into the mold space such as a closed cavity. The product is removed from the pair of molds and transferred to a hot press.

[0254] Advantageously, the pair of molds comprises an upper mold and a lower mold. The upper mold is movable and the lower mold is fixed.

[0255] In the closed mold space, the molds may be spaced apart from each other during forming. After being spaced apart, the pair of molds provides a space for additional foam to enter.

[0256] In practice, the distance between the molds is 10 to 100 mm, preferably 20 to 60 mm. Generally, the thicker the layer, the greater the distance. The flow rate of the foam is maintained at a moderate level. The actual flow rate is 1 to 3 meters per second.

[0257] As mentioned above, a plurality of identical products can be obtained in parallel by a forming method wherein each mold of the pair is provided with a plurality of identical partial molds or sub-molds.

[0258] Each partial mold or sub-mold is uniformly filled with foam. Therefore, the products are uniform and the process is rapid.

[0259] After the mold space is filled with foam, pressing is performed to remove moisture and air. While fibers accumulate on the mold surfaces, water and air can pass through the mold surfaces. Water removal can be accelerated by vacuum. Water removal can also be accelerated by excess pressure applied by the opposing molds.

[0260] It is to be understood that the disclosed embodiments of the present invention are not limited to the specific structures, process steps, or materials disclosed herein, but extend to equivalents thereof, as would be recognized by one skilled in the relevant art. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0261] Throughout this specification, any reference to “one embodiment” or “a particular embodiment” means that certain features, structures, or characteristics described in relation to that embodiment are included in at least one embodiment of the present invention. Therefore, the phrases “in one embodiment” or “a particular embodiment” appearing in various places throughout this specification do not necessarily all refer to the same embodiment.

[0262] Where used herein, multiple items, structural elements, components, and / or materials may be presented in common lists for convenience. However, these lists are to be interpreted as if each element of the list were individually identified as a distinct and unique element. Therefore, individual elements of such lists should not be interpreted, without the opposite indication, as being substantially equivalent to other elements of the same list based solely on their representation within a common group. Furthermore, various embodiments and examples of the invention may be referenced herein along with alternatives for their various components. It should be understood that such embodiments, examples, and alternatives should not be interpreted as substantially equivalents of each other, but should be considered as distinct 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. The following description provides many specific details, such as examples of length, width, and shape, to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that the invention can be carried out without one or more specific details, or using other methods, components, materials, etc. In some cases, known structures, materials, or operations are not illustrated or described in detail to avoid obscuring aspects of the invention.

[0264] While the aforementioned examples illustrate the principles of the present invention in one or more specific applications, it will be apparent to those skilled in the art that numerous modifications can be made in terms of form, usage, and implementation details without affecting the inventive step and without departing from the principles and concepts of the present invention. Therefore, the present invention is not intended to be limited except as provided in the claims below.

[0265] In this document, the verbs “to include” and “to provide” are used as open limitations that do not exclude or require the existence of features not mentioned. Features described in dependent claims may be freely combined with each other unless otherwise explicitly stated. Furthermore, it should be understood that the use of “a” or “an,” i.e., the singular form, throughout this document does not exclude the plural form. [Industrial applicability]

[0266] The present invention is industrially applicable, at least in the manufacture of multilayer fiber molded articles.

[0267] BCTMP Bleached Chemithermo-Mechanical Pulp MFC (Microfibrillated Cellulose) NFC-modified nanofibrillated cellulose [Explanation of Symbols]

[0268] 1. First fiber layer 2. Second fiber layer 3. Inner fiber layer 4. Middle Class 5. Non-fiber release layer

Claims

1. Oven-safe molded multilayer textile product, A first fiber layer containing cellulose fiber material, A second fiber layer located above the first fiber layer, the second fiber layer comprising a cellulose fiber material, and the second fiber layer located above the first fiber layer, The first and / or second fiber layers exhibit barrier properties substantially throughout their entire structure. The oven-safe molded multilayer fiber product is configured to heat food or liquid on top of it to at least 100°C. Here, the oven-safe molded multilayer fiber product further includes a non-fiber-release layer on the second fiber layer, forming the uppermost layer of the oven-safe molded multilayer fiber product when in use. The non-fiber release layer is configured to facilitate the release of food or liquid from the oven-safe molded multilayer fiber product after it has come into direct contact with food or liquid and has been heated thereon. Oven-safe molded multilayer textile products.

2. The oven-safe molded multilayer fiber product according to claim 1, wherein the non-fiber release layer comprises a silicone composition.

3. The dry basis weight of the non-fiber peeled layer is 0.5 to 2.5 g / m². ２ The oven-safe molded multilayer fiber product according to claim 1 or 2.

4. The oven-safe molded multilayer fiber product according to claim 1 or 2, wherein the first fiber layer forms the bottom fiber layer of the oven-safe molded multilayer fiber product when in use, and the second fiber layer forms the top fiber layer of the oven-safe molded multilayer fiber product when in use.

5. The oven-safe molded multilayer fiber product according to claim 1 or 2, wherein the barrier properties include one or more of oil resistance and grease resistance, water resistance, water vapor resistance, fragrance resistance, gas resistance, and oxygen resistance.

6. The oven-ready molded multilayer fiber product according to claim 1, wherein the first and / or second fiber layers are substantially oil-resistant and grease-resistant throughout their structure.

7. The oven-ready molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein the first and / or second fiber layers are substantially water-resistant and / or water vapor-resistant throughout their structure.

8. The oven-ready molded multilayer fiber product according to any one of claims 1, 2, or 6, further comprising one or more inner fiber layers between the first fiber layer and the second fiber layer, each comprising a cellulose fiber material.

9. The oven-safe molded multilayer fiber product according to any one of claims 1, 2, or 6, 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.

10. The oven-safe molded multilayer textile product according to any one of claims 1, 2, or 6, wherein the first fiber layer forms the bottom fiber layer of the oven-safe molded multilayer textile product and has higher water resistance and / or higher water vapor resistance than the fiber layer above it.

11. The oven-safe molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein the cellulose fiber material of the fiber layer of the oven-safe molded multilayer fiber product contains or consists of bleached chemical wood pulp.

12. The oven-ready molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein the cellulose fiber material of the first and / or second fiber layers comprises cellulose fibers refined to a Shopper-Leighler number of 40 or more.

13. The oven-safe molded multilayer textile product according to any one of claims 1, 2, or 6, wherein the number of Shopper Leaguers in the bottom fiber layer and / or one or more inner fiber layers of the oven-safe molded multilayer textile product is less than 50.

14. The density of the second fiber layer is greater than the density of the fiber layer below it, and the density of the second fiber layer, when calculated as dry solid weight per unit volume, is 300 to 1000 kg / m³. ３ An oven-safe molded multilayer fiber product according to any one of claims 1, 2, or 6, which falls within the range of [the specified range].

15. The density of the bottom fiber layer and / or one or more inner fiber layers of the oven-compatible molded multilayer fiber product is 500 kg / m³. ３ An oven-safe molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein the product is less than [amount missing].

16. The oven-ready molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein at least one of the fiber layers contains one or more additives from among pigments, barrier agents, binders, and sizing agents.

17. The oven-safe molded multilayer fiber products are 5 to 900 g / m². ２ An ovenable molded multilayer fiber product according to any one of claims 1, 2, or 6, having a dry basis weight in the range of .

18. The top and / or bottom fiber layers of the oven-safe molded multilayer fiber product are 20 to 150 g / m². ２ An ovenable molded multilayer fiber product according to any one of claims 1, 2, or 6, having a dry basis weight in the range of .

19. The oven-safe molded multilayer fiber product is a three-dimensional molded multilayer fiber product obtained by using a mold that includes at least one three-dimensional non-planar mold surface, wherein the oven-safe molded multilayer fiber product exhibits a three-dimensional shape that conforms to the shape of the three-dimensional non-planar mold surface, according to any one of claims 1, 2, or 6.

20. The oven-safe molded multilayer fiber product according to any one of claims 1, 2, or 6, wherein the oven-safe molded multilayer fiber product is an oven-safe or micro-oven-safe food or liquid packaging, container or tray, or container for baking or cooking.

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