FI13463Y1 - Moulded and coated fibrous product - Google Patents

Abstract

A product comprising: a fibrous structure, comprising cellulosic and/or lignocellulosic fiber material and which has been achieved by a casting process; and a surface coating (5), such as at least one surface layer, on at least one side of the fibrous structure, characterized in that: the surface coating has been achieved with a dry coating process, preferably a powder coating process, wherein the density of the fibrous structure to be surface coated in said dry coating process is greater than 500 kg/m³, calculated as the weight of the dry material per volume, and the square weight of the product as dry is in the range 5 – 900 g/m².

Description

Molded and coated fibrous product

FIELD OF THE INVENTION

[0001] The present invention concerns coated fibrous structures, and more specifically, molded fibrous structures that comprise cellulose and/or lignocellulose fibers.

BACKGROUND OF THE INVENTION

[0002] Fibrous structures comprising cellulose and/or lignocellulosic fibers — are produced, for example, by wet-laid, air-laid or mold methods.

Such fiber-rich structures are widely used in packaging technology as an alternative to completely plastic-based packaging.

[0003] It is known to add various coating films, such as barrier coatings, to packages and containers made of cellulose fiber material, such as cardboard.

The purpose of such coating films is often to provide customized or improved surface properties to the fibrous structure.

[0004] The application of the barrier coating must typically be carried out in a separate process after the actual production of the fiber substrate. For example, food containers and packaging are today made of paper or cardboard with plastic or wax-based barrier coatings on the side of the container in contact with the food,

S

N such as laminated or extruded barrier coatings which have been prepared

N b of polyethylene terephthalate or polyethylene.

O

N [0005] Known coating films have many disadvantages related to the

E for adhesion to the rest of the product and deterioration of the mechanical properties of the coating film > 25 — during — manufacture — drying and conversion stages or

I during humidity fluctuations during transport and storage. For example, the coating may o shrink in a different way compared to the substrate on which the coating is placed. Shrinkage problems are particularly relevant when using bio-based coating compositions diluted with water.

[0006] Water-based coatings are usually associated with many challenges and requirements for a fiber-based substrate, such as structural problems in connection with rewetting and the need for re-drying.

[0007] With known methods, it is challenging to produce an even coating on a three-dimensional substrate or object, and in particular to achieve an even distribution of the coating material on the side walls and bottom of the object.

[0008] There are still challenges in the known deep drawing forming processes, because the laminated or coated substrate must be press-moldable and also flexible enough so that the coating does not crack in the process. — [0009] The purpose of the present invention is to solve at least some of the problems occurring in known technology.

SUMMARY OF THE INVENTION

[0010] The invention is defined by the characteristics of independent protection claims. Some — special forms of implementation are defined in non-independent protection requirements.

According to the first aspect of the present invention, a product is provided which comprises: a fibrous structure which comprises cellulose and/or lignocellulosic fiber material and which has been obtained by a casting process; and on at least one surface of the fibrous structure of the coating, such as at least one coating layer, — where the coating has been obtained by a dry coating method, preferably by 2 powder coating methods. & > [0012] Different forms of application according to the first aspect can comprise

O n at least one trait from the following bulleted list:

OF

E e The coating forms the top layer or the bottom layer of the product. — . . . 2 25 e The product comprises at least two coating layers, which are located on a fiber-rich <t

AN on different surfaces of the structure, such as opposites of the planar fibrous structure

O

S on the sides.

e The product additionally comprises a non-fibrous intermediate layer between the said coating and the fibrous structure. e The coating is applied to a curved or non-horizontal surface of a fibrous structure. e The coating is a non-fibrous coating and comprises or consists of thermoplastic polymer material or thermoplastic polymer material such as polyolefin, polyester, PET, polyhydroxyalkanoate or polylactic acid. e The coating comprises a non-fibrous layer comprising or consisting of a biodegradable thermoplastic polymer material. e The coating comprises at least 80% by weight, such as at least 90% by weight of thermoplastic polymer material or thermoplastic polymer material. e A coating is a functional coating adapted to change the functional — properties of the surface, = such as — barrier properties, — visual properties, functional properties and/or haptic properties. e The coating or part of it is adapted to increase the barrier properties of the surface of the fibrous structure, and the barrier properties include one or more of the following: oil and grease resistance, liquid resistance, water resistance, water vapor resistance, aroma resistance, gas resistance, oxygen resistance, aroma barrier. e The coating is adapted to change the surface hardness, microscopic roughness, macroscopic roughness, friction properties, 0) of the fibrous structure. . . . ve ® as

N tactile properties or color.

OF

2 e Is the dry square weight of the product in the range 5-900 g/m? for example in the range 100-800 = g/m", such as in the range 200-600 g/m". x - e The dry square weight of the coating is in the range 2-80 g/m", for example 10-35 g/m?.

O

3 < 25 e The thickness of the coating is at least 1 um, such as in the range 2-50 pm, for example 5-30

S m

N Hmm. >” e The fiber-rich structure is essentially free of plastic materials and resin.

e The fibrous structure is a multi-layered fibrous structure and comprises at least a first fibrous layer and a second fibrous layer, each of which comprises cellulose and/or lignocellulosic fiber material. e The product additionally comprises between the first and second fibrous layers one or more fibrous inner layers, each of which comprises cellulose and/or lignocellulosic fiber material, preferably comprising mechanical pulp, such as

CTMP or BCTMP and/or wreckage. e Cellulose and/or lignocellulosic fiber material comprises one or more of the following: bleached or unbleached chemical pulp, semichemical pulp, mechanical pulp, thermomechanical pulp, chemithermomechanical pulp, bleached — chemithermomechanical — pulp, — recycled — cellulose = and/or lignocellulosic fibers, fibrillated cellulose , such as microfibrillated cellulose or nanofibrillated cellulose, nanocellulose, scrap, cellulosic by-products, regenerated cellulosic fibers, and any other cellulosic material comprising cellulosic fibers or parts of cellulosic fibers, derived from any perennial or annual plant. e The fiber-rich structure comprises at least 50% by weight of cellulose and/or lignocellulosic fiber material, calculated from the total dry matter. e One or more of the fibrous layers or the entire fibrous structure has been obtained by — foam forming, — water forming, dip forming, vacuum forming, compression forming, thermoforming or n dry forming or any combination of these.

OF

> e Fibrous structure is a three-dimensional molded fibrous structure that is = obtained using a mold comprising at least one three-dimensional, non-

N 25 planar mold surface, whereby the said fibrous structure shows

E of a three-dimensional shape consistent with said three-dimensional, non-3-planar mold surface. 5

N e An article or part thereof has an overall shape adapted to hold a liquid or flowing 5 material, such as the overall shape of a cup or bowl.

[0013] According to the second aspect of the present invention, the use of the product according to the first aspect is achieved as a package or storage container for food, such as dairy, fish or meat products, or as a package for medicines or cosmetics, or as a part thereof. 5 [0014] According to the third aspect of the present invention, the use of the product according to the first aspect is achieved for storing, processing, preparing or cooking food.

[0015] According to the fourth aspect of the present invention, a method is provided which comprises the following: at least one fiber-rich composition is provided which comprises cellulose and/or lignocellulosic fibers and water; in a mold, molding said at least one fibrous composition into a fibrous structure; applying a coating, such as at least one coating layer, to at least part of the surface of the cast — fibrous — structure — by means of a dry coating process, — preferably by means of a powder coating process. — [0016] The different application forms of the fourth aspect can comprise at least one feature from the following bulleted list: e Said molding step = comprises molding a three-dimensional — fibrous — structure from said at least one fibrous composition using a three-dimensional mold. e Said powder coating process — comprises applying dry powder electrostatically to said surface of the fibrous structure and curing or melting the applied powder 2, preferably contact or non-contact heating and/or

N by means of hot pressing, to form a film. & 2 e The dry matter content of the fibrous structure to be coated is at least 90%,

I 25 like 90-96%. a

S e Dry powder comprises pigments, binders and in addition one or more s additives, which additives can be selected from the following group: resins and

S fillers such as barite, silica, carbonates, silicates, aluminum hydroxide, and > mixtures thereof. e Said applying includes spraying.

e Said — curing or = melting = comprising — contact or = non-contact heating, hot pressing, IR curing or microwave curing, or any combination thereof, preferably contact or non-contact heating to a temperature of at least 80°C, for example at least 120 *C, like at least 150 *C. e Said molding includes water forming, foam forming, dip forming method, vacuum forming, compression molding, thermoforming or any combination thereof, preferably foam forming. e The method further comprises the following after said molding step and before applying the coating: removing water from the structure; a structure from which water has been removed is hot-pressed to obtain a cast three-dimensional fibrous structure, whereby said hot-pressing produces a surface that is directly suitable for dry coating, such as powder coating, for example powder painting. — [0017] Advantages of the invention

[0018] The present invention may facilitate the production of smooth and flat coating films for fibrous substrates, especially for three-dimensional fibrous substrates.

[0019] The present invention may make it easier to obtain a sufficiently smooth substrate to successfully produce a smooth coating on the substrate, for example, by means of a dry coating process such as a spraying process. n [0020] The present invention may provide fiber products with improved

S surface properties such as barrier, optical, visual and/or haptic properties.

S [0021] There may be problems related to insufficient adhesion of the coating film

N to avoid.

I

Ao - 25 10022] Dry coating, like powder coating, may have many advantages

S compared to — wet painting processes. — To be painted — object — past — sprayed

N powder coating composition can be recovered and reused, reducing 5 waste and costs compared to wet painting processes. After the powder-coated objects have cooled, they can be stacked or packed against each other without the risk of sticking to each other. The powder coating process is faster than wet coating. A powder-coated surface is typically not susceptible to cracking after impact or bending.

[0023] The present invention may facilitate the use of bio-based raw materials in coatings or paints intended for molded fibrous products.

[0024] The present invention may enable the film formation of a dry coating, such as a paint, by several methods, such as contact heating, oven heating, microwave heating or infrared heating or any combination thereof.

[0025] With the help of the present method, the problems related to the rewetting of the fibrous substrate may be avoided and, more generally, the need for water use may be reduced compared to known water-based coating methods.

[0026] In the present method, a separate conversion step is not necessarily needed, because the coating can be produced in a step that is integrated into the existing production line. — [0027] The present invention, especially powder painting, may enable functional materials, such as thermal insulation material, to be imported onto the surface.

[0028] The present invention may enable the production of molded fibrous products with a pattern on the surface.

[0029] The present product may provide one or more of the following: high heat resistance, non-flammability, excellent shape tracking or dimensional stability, 2 strength, load capacity of functional material, acid resistance, improved flexibility,

Oh Lol. . yes

N improved gas barrier properties or grease and/or water resistance. 3 n [0030] The present invention may be suitable for indicative packaging or

N r for temperature-controlled packing. = > 25 [0031] Any oil may be used for the presented structures and products

For packaging and storage and manufacturing of products containing I and/or containing water, such as food or medicine or o cosmetics.

D

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 schematically shows a coated fibrous structure according to at least some embodiments of the present invention.

FORMS OF APPLICATION

[0033] Unless otherwise stated herein or is clear from the context, all percentages referenced herein are expressed as weight percents based on the total dry weight of the respective composition.

[0034] In the present context, "dry coating" typically means any suitable coating method in which the coating material is applied or deposited on the surface in a dry state, for example as dry particles or dry powder or dry paint.

[0035] In the present context, powder coating? typically means a coating method in which essentially dry powder or — dry paint is applied or layered on the surface, typically by means of an electrostatic coating method.

[0036] In the present context, 'coating' means a coating that may consist of one or more coating layers that may have been formed in the same coating process or in different coating processes.

[0037] In the present context, *'resistant', such as water-resistant, means that — the material or layer resists the penetration of the substance in question. = Cheap

S

In N embodiments, the material or layer has a "repellency" such as water repellency, which

N b means that the substance in question cannot easily penetrate through the material or layer.

O n In a more affordable embodiment, the material or layer has "hold", such as

N r water resistance, which means that the substance in question cannot penetrate the material or

Ao = 25 — during typical use of the material mentioned in the layer or the product containing the layer.

O

2 In other words, the resistance of the substance in question against the penetration of the substance increases <t

S in the order "resistant" < "repellent" < "holding".

OF

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[0038] In the present context, also every reference to 'durability' means *at least durable', i.e., the material or layer can also have repellency and even durability.

[0039] The present invention offers new molded and coated fibrous products. At least part of the product can be manufactured by a foam-based process.

Foam molding enables the manufacture of cast multi-layer structures at low cost and the customization of the properties of individual layers.

[0040] According to the present invention, the product comprises: a fibrous structure, which comprises cellulose and/or lignocellulosic fiber material and is obtained by a casting process; — and a coating, such as at least one coating layer on at least one surface of a fibrous structure, in which case the coating has been obtained by a dry coating method, preferably by a powder coating method.

[0041] The coating can consist of one coating layer or alternatively the coating can comprise several coating layers, such as 2-10 coating layers on top of each other. — [0042] The coating can form the uppermost exposed surface or layer or the lowest exposed surface or layer of the product.

[0043] The coating can form the top or bottom, typically present, non-fibrous layer of the product.

The product can comprise at least two coatings that are located on different surfaces of the fibrous structure, such as on opposite sides of a planar fibrous structure or on different sides of a three-dimensional structure. The coatings can each consist of one or ™

S from several coating layers.

OF

O [0045] The product can comprise at least two coating layers which are located

N on different surfaces of a fibrous structure, such as on opposite sides of a planar fibrous structure z 25 — or on different sides of a three-dimensional structure. — . . . . . . . . . . . 2 [0046] The product can also comprise a non-fibrous or fibrous intermediate layer, <t

S for example a primer layer or a flame pretreatment layer, said coating and

O

S between the fibrous structure.

[0047] The product may comprise another coating in addition to the coating according to the present invention. Although the present coating is produced by a dry coating method, a possible additional coating can be produced by any method, for example a wet coating method. The additional coating can be located under or alternatively on top of the existing — coating produced by the dry coating method.

[0048] In one embodiment, the coating layer is applied to the curved or non-horizontal surface of the fibrous structure.

[0049] The coating or a part of it may comprise thermoplastic polymer material or thermoplastic polymer material. — [0050] The coating is — typically — a non-fibrous — layer and = comprises or consists of thermoplastic polymer material or hard plastic polymer material such as polyolefin, polyester, copolyester, PET, nylon, polyhydroxyalkanoate or polylactic acid. The polyolefin may comprise polyethylene and/or polypropylene.

[0051] In some embodiments, the coating is a non-fibrous layer and consists of — or consists of a biodegradable thermoplastic polymer material.

[0052] In some embodiments, the coating is a non-fibrous layer and comprises or consists of a bio-based or non-fossil-based thermoplastic polymer material.

[0053] In one — embodiment — the coating layer — comprises — at least = 50% by weight, such as at least 80% by weight, such as at least 90% by weight — thermoplastic polymer material or thermoplastic polymer material. 2 [0054] The coating may comprise a functional layer adapted to change

N functional properties of the surface, such as barrier properties, optical properties

O and/or haptic properties. &

I [0055] The coating can be adapted to increase the barrier- a = 25 — properties of the surface of the fibrous structure. Barrier properties may include one or more of the following: oil and

O

2 grease resistance, liquid resistance, water resistance, water vapor resistance, <t

S aroma resistance, gas resistance, oxygen resistance, aroma barrier.

OF

>"

[0056] The coating can be adapted to change, for example, the hardness, microscopic roughness, macroscopic roughness or friction properties of the surface of the fibrous structure.

[0057] In some embodiments, the coating can be used to create — visual and/or tactile effects on the surface, such as color, metallization effects, color swirls, waves, drop-like bumps, crater-like cavities, stripes with variable transparency, or 3D effects for anti-counterfeiting and security purposes.

[0058] In some embodiments, the coating provides surface properties, such as an artificial leather surface, an anti-slip surface or embossing effects. — [0059] Still — in some other embodiments, the coating can provide a finish layer that can be detected by touch, or a layer whose color can be changed by electrical or other physical impulses, or a layer that can produce a visual reflectivity or depth effect.

[0060] The dry square weight of the product can be in the range 5-900 g/m", for example in the range — 100-800 g/m", such as in the range 200-600 g/m".

[0061] The dry square weight of the coating can be in the range of 2-80 g/m², such as in the range of 2-35 g/m", for example in the range of 10-30 g/m".

[0062] In one embodiment, the thickness of the coating is at least 1 µm, such as in the range 2-50 µm, for example 5-10 µm. — [0063] The structure 2 of the fibrous structure according to some embodiments is discussed below. & > [0064] The fibrous structure preferably comprises at least 30% by weight, such as

At least 50% by weight, such as 50-95% by weight of fibrous cellulose and/or

N r of lignocellulosic material calculated from the total dry weight. = > 25 — [0065] The fibrous structure is preferably substantially free of plastic material and

IF resin.

O

S

S [0066] The fibrous structure can be a single-layer fibrous structure.

[0067] The fiber-rich structure can alternatively be a multi-layer fiber-rich structure. A multi-layered fibrous structure can comprise at least two fibrous layers, for example a first fibrous layer and a second fibrous layer, both of which comprise cellulose and/or lignocellulosic fiber material.

[0068] The product can also comprise between the first and second fibrous layers one or more fibrous inner layers, each of which comprises cellulose and/or lignocellulosic fiber material.

[0069] The — fiber compositions of the layers — can be mutually = different or — alternatively, be the same.

[0070] The fibrous structure to be coated or the layer of the fibrous structure to be coated may comprise additives, such as pigments and/or fillers, adapted to facilitate the dry coating process. The mentioned additives can, for example, increase the moisture content, smoothness and/or surface energy of the structure or layer to be coated. — The square weight of the fiber layer containing additives can be in the range of 30-400 g/m".

[0071] Thanks to the multi-layer fiber-rich structure, the compressibility of the structure can be easier to customize, which can be advantageous in terms of the dry coating process.

Cellulose and/or lignocellulosic fiber material may contain one or more of the following: chemical pulp, semi-chemical pulp, mechanical pulp, thermo-mechanical pulp, chemi-thermo-mechanical pulp, bleached chemi-thermo-mechanical < pulp, bleached semi-chemical pulp, wood dust, pressure dust, stone dust, recycled

N cellulose and/or lignocellulosic fibers, fibrillated cellulose such as microfibrillated 3 cellulose or nanofibrillated cellulose, nanocellulose, scrap, cellulose by-products,

N 25 — regenerated cellulose fibers and/or other lignocellulosic material containing cellulose fibers or parts of cellulose fibers z. 2 [0073] The pulp can be bleached or unbleached or a mixture thereof.

OF

2 [0074] The pulp can be ground or unground or a mixture thereof.

D

The chemical pulp can originate from any chemical pulp production method, such as the sulfate method, the sulfite method or the organosolv method.

[0076] The mechanical pulp can come from any mechanical pulping method, such as mechanical pulp, thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), bleached chemithermomechanical pulp (BCTMP), semichemical pulp, grit (GW), pressure grit (PGW), stone grit (SGW) and their combinations.

[0077] The wreck may comprise an edge wreck.

[0078] Cellulose and/or lignocellulosic fiber material can comprise pulp originating from other than wood.

[0079] In one embodiment, the pulp can be made from any hardwood, such as wood of the betulaceae family, for example birch or aspen, salicaceae family, eucalyptus, tropical hardwoods or pines, or any combination of the above. The pulp can also be made from any softwood, such as spruce or pine, or any combination thereof. The pulp can also be made from a combination of hardwoods and conifers.

[0080] In one embodiment, the pulp can be made from any annual plant, such as straw, reeds, reeds, bamboo, — sugar cane, sugar cane waste or any grass plant.

[0081] In one embodiment, the cellulose & and/or lignocellulosic fiber material of the fibrous structure or its part comprises bleached chemical hardwood pulp and

N chemical chemithermomechanical pulp, such as 10-50% by weight of bleached chemical = hardwood pulp and 50-90% by weight of bleached chemithermomechanical pulp of the total dry matter. a

S [0082] Typically, one or more surface layers of the product may comprise a chemical

I pulp, such as bleached chemical pulp, for example, bleached chemical

S hardwood pulp, for example bleached chemical birch pulp.

D

[0083] In one embodiment, one or more of the fibrous inner layers may comprise or consist of mechanical pulp, such as CTMP or BCTMP, and/or scrap, for example 60-95 wt% BCTMP and 5-40 wt% scrap , of total dry matter.

[0084] In some embodiments, the cellulosic and/or lignocellulosic fiber material — comprises pulp, such as bleached chemical pulp, which is essentially lignin-free, which can make the product particularly suitable for cooking, heating and safe contact with foodstuffs.

[0085] The advantage of first pulp is that it is free of ink residue and other unwanted chemicals. Recycled waste materials often contain chemical and — microbiological impurities that can affect their safe use.

Mixtures of chemical compounds and microbial products can leach out of recycled materials and cause various negative health or environmental effects. Fi only = the harmfulness of individual chemical compounds, but also their interactions with other chemical compounds and microbial products — can increase the toxicity of recycled materials and their emissions. Therefore, the present invention advantageously avoids the use of recycled materials.

[0086] The advantage of chemical pulp, such as bleached chemical pulp, is that it is essentially lignin-free. Pulps containing lignin can be sensitive to aging and yellowing of the material.

[0087] In some embodiments, the cellulose and/or lignocellulosic fiber material comprises lignin, for example in the form of fibrous lignocellulosic material, such as bleached or unbleached mechanical pulp. The present invention can benefit from the presence of & lignin in the fibrous structure. Because the fibrous structure is on top

A coating layer, possibly lignin-containing fibrous material or layer is separated e 25 — from the environment, for example from the food content of the package.

E [0088] In one embodiment, cellulose and/or lignocellulosic fiber material or

S part of it comprises or consists of bleached chemical softwood pulp.

O

<

N [0089] In one embodiment, cellulose and/or lignocellulosic fiber material or

S part of it comprises or consists of bleached chemical hardwood pulp.

[0090] Any suitable molding method, such as injection molding, vacuum molding, compression molding, transfer molding, extrusion molding, blow molding, dip molding, rotational molding, foam molding, lamination, — deep drawing, thermoforming, compression molding, hydroforming, can be applied to the production of the cast fibrous structure or its part. , suction molding, closed mold molding, open mold molding, dry molding, or foam molding, or any combination thereof.

[0091] In the present context, the terms 'moulding' and 'forming' can be used in the same sense. — [0092] The molding method can be supplemented with additional processes, such as various molding processes, for example in-mold drying, cold and hot pressing, calibration pressing, bending or cutting, or machining processes, such as turning, drilling, shaping, sharpening, heat sealing, printing or finishing, or any combination of these. — [0093] In one preferred embodiment, one or more fiber layers of a fibrous structure or the entire fibrous structure has been obtained either by foam forming or water forming or wet forming in a mold, preferably by foam forming in a mold.

[0094] The fibrous structure can be a three-dimensional molded fibrous structure obtained by using a mold comprising at least one three-dimensional, non-planar mold surface. In this case, the fibrous structure has a three-dimensional shape corresponding to the shape of said three-dimensional, non-planar mold surface. < [0095] The product or its part may have an overall shape adapted to a liquid or

N for holding fluid material, such as the overall shape of a cup or bowl. & e [0096] In one embodiment, the oil and grease resistance OGR of the product is measured - 25 according to ASTM F119 with olive oil at 60 °C and is at the level of "moderate" or a better, such as more than 10 min, typically 10 min - 6 h , in one example more than 3 3 hours. 3 2 [0097] In one embodiment, the moisture resistance of the product is measured according to ISO 2528 > and ASTM F96 under standard conditions of 23 *C and 50% RH, and is at the level of "moderate" or better, such as less than 250 g /m?/d, typically 100-250 g/m?/d, in one example less than 150 g/m?/d.

[0098] In one embodiment, water absorption on the coated side or surface of the product is measured by the Cobb value of ISO 535 after 5 minutes and is at a level of "moderate" or better, such as less than 100 g/m? typically 50-100 g/m", in one example less than 75 g/m".

[0099] The density of the fibrous structure to be coated is preferably in the range 300-1000 kg/m", such as 350-800 kg/m", for example 450-700 kg/m", such as greater than 500 kg/m", calculated as the weight of dry substances per volume for. — [00100] In some embodiments, the density of the fibrous structure may be relatively low, such as less than 500 kg/m', because the presence of the powder coated layer may provide a dense, closed structure or surface layer over the fibrous structure.

[00101] The surface smoothness of the fibrous structure to be coated is preferably in the range 50-3000 ml/min, such as 100-1000 ml/min, for example 150 to 600 ml/min, measured by the ISO 8791-2 Bendtsen method. The advantage of a smooth surface is that powder coating, for example by spraying, is easier.

[00102] A fibrous structure to be coated or a part thereof, such as a fibrous layer of a fibrous structure, may comprise one or more additives or additive chemicals.

In one embodiment, at least the surface layer or part of the surface to be coated of the fibrous structure comprises one or more additive chemicals.

[00103] The fibrous structure to be coated or its part, such as fibrous structure & fibrous layer, may comprise one or more of the following additives: pigments,

N such as — talc, clay, calcium carbonate, and = metallic salt pigments, — for example 5 aluminum trihydrate, gypsum, silicates, silica compounds, and titanium dioxide; barrier substances;

N 25 — latex binders; water-soluble binders such as PVA (polyvinyl alcohol), starch

S and CMC (carboxymethyl cellulose); adhesives such as AKD (alkyl ketene dimer or 3 alkenyl ketene dimer), ASA (alkenyl succinic anhydride) and resins; reinforcements, 5 such as CMC, MFC (microfibrillated cellulose) and NFC (nanofibrillated cellulose). 5

[00104] In one embodiment, the additives comprise additives, such as pigments, which are able to increase the smoothness of the surface to be coated.

[00105] In one embodiment, the surface to be coated is made more hydrophobic by including suitable additives in the fibrous structure or its surface, such as hydrophobizing agents, such as surface adhesives, for example alkyl ketene dimer (AKD) and/or starch.

[00106] In one embodiment, the surface to be coated is made more hydrophilic by including suitable additives in the fibrous structure or its surface, such as hydrophilizing agents.

[00107] The amount of additives can be in the range of 0.01-30% by weight, such as 0.01-10% by weight, such as 0.1-8% by weight, for example 1-5% by weight, calculated from the total dry matter.

[00108] Additives or chemicals can be added to the fiber pulp or slurry before the molding step, preferably the foaming step, the consistency being for example 0.5-15%, such as 2-10%, or alternatively before molding, preferably before foaming, for example to the foam to be mixed with the fiber slurry. — [00109] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight of talc.

[00110] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight of clay.

[00111] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight calcium carbonate. 2 [00112] In one embodiment, a fibrous structure or at least one thereof

N of the fiber-containing layers comprises barrier materials selected from the following group: 3 dispersion polymers, polyolefins, polyesters, other thermoplastic polymers,

N biodegradable polymers such as polylactic acid, starch and its derivatives, plastomers,

E 25 — elastomers, ethylene vinyl alcohol, and any of their derivatives, copolymers and

O mixtures. 3 3 [00113] In one embodiment, a fibrous structure or at least one thereof

N of the fibrous layers comprises 0.1-10% by weight, such as 0.1-5% by weight of barrier substances, such as dispersion polymer barrier substances. Such barrier substances typically provide — barrier properties through a fibrous structure or a fibrous layer.

[00114] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight polymeric latex binders, such as styrene butadiene latex, styrene acrylate latex, polyvinyl acetate latex.

[00115] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight of polyvinyl alcohol (PVA).

[00116] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-20% by weight, such as 0.1-5% by weight of starch.

[00117] The starch can be native, boiled or swollen cationic starch.

[00118] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-5% by weight of carboxymethylated cellulose (CMC).

[00119] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-20% by weight of mineral fillers.

[00120] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-20% by weight of pigments from the total dry substance. — The surface layer or part of the surface to be coated preferably comprises 0.1-20% by weight of pigments.

[00121] In one embodiment, the fibrous structure or at least one of its fibrous layers comprises 0.1-20% by weight of reinforcing additives, such as microcrystalline cellulose (MCC), nanocellulose or other reinforcing cellulose.

[00122] The fibrous structure or at least one of its fibrous layers comprises — preferably less than 5% by weight, such as less than 2% by weight of waxes, plastics and fluorochemicals.

S

N In one embodiment, a fibrous structure or at least one of its fibrous structures

N b of the layers comprises less than 2% by weight of waxes. In one embodiment, fiber-rich

O's structure or at least one of its fibrous layers comprises less than 2% by weight, such as less than 1

OF

I weight-% plastics. In one embodiment, the fibrous structure or at least one of its a = 25 fibrous layers comprises less than 2% by weight, such as less than 1% by weight, of fluorochemicals. 3 3 [00123] In some embodiments, the product contains essentially no waxes, plastics and fluorochemicals, especially plastics.

D

[00124] In products intended for food packaging applications = additives and foaming chemicals can be selected from all additives approved for use in food packaging materials or packaging. "Materials that come into contact with foodstuffs" means all materials and accessories intended to come into contact with foodstuffs, such as packaging and containers.

[00125] The amount of barrier additive in the fibrous structure or its parts can be — in the range of 1-10% by weight, such as 5-8% by weight, calculated from the total dry weight of the fibrous layer.

[00126] In some embodiments, the coating or part thereof may provide barrier properties of the first type, and the underlying fibrous structure may provide barrier properties of a second type that differ from the first type of barrier properties. The coating or part of it can provide, for example, water barrier properties, and the fibrous structure can provide oil and/or grease barrier properties.

[00127] In some embodiments, the coating or its part can enhance barrier properties, such as oil and/or grease barrier properties, which are produced by the fibrous structure underneath it. — [00128] If the product comprises an additional coating either above or below the coating produced by the dry coating method, said additional coating can also provide barrier properties. A coating produced using a dry coating method can, for example, provide oxygen barrier properties, while an additional coating produced using a wet coating method can provide different barrier properties, such as water barrier properties. — [00129] The presented coated structure can be used in materials and goods that come into contact with foodstuffs. & [00130] In one embodiment, the present product complies with Regulation (EC) No. > 1935/2004.

O

N [00131] In addition to or instead of food contact uses for these structures and products

E 25 — many other areas of application can be designed. 3 [00132] In one embodiment, at least one of the fibrous layers comprises an adhesive (size), such as modified rosins, waxes, oils or polymers. Glue-

The advantage of using substance S is that the unwanted absorption of liquid and/or water and/or moisture = into the foam-formatted — structure — can be — reduced. The moisture resistance or water resistance of the product is thus improved.

[00133] One example of a wax is alkyl ketene dimer (AKD). One example of an oil is alkenyl succinic anhydride (ASA). One example of a polymeric adhesive is styrene acrylate emulsion (SAE).

[00134] A preferred adhesive is AKD or a similar wax.

[00135] In some embodiments of the present invention, usable adhesives can be a cationic surface adhesive or an anionic surface adhesive, such as a rosin-based adhesive. In addition to these or as an alternative, some reactive adhesives such as alkyl ketene dimer (AKD) can be used as a surface adhesive.

[00136] Suitable cationic adhesives include cationic starches and — starch derivatives = and — corresponding — carbohydrate-based — natural polymers.

Synthetic polymers can be used, for example, styrene/acrylate copolymers (SA), polyvinyl alcohols, polyurethanes and alkylated urethanes.

[00137] Suitable anionic adhesives include anionic starches and starch derivatives and similar carbohydrate-based natural polymers such as — carboxymethyl cellulose and its salts, alkyl celluloses such as methyl cellulose and ethyl cellulose. Synthetic polymers may include: styrene/maleic acid copolymer ~~ (SMA), — diisobutylene/maleic anhydride, styrene acrylate copolymers, acrylonitrile/acrylate copolymers, and polyurethanes and similar latex products containing the same chemical functionalities.

[00138] In one embodiment, the adhesive comprises an alkyl ketene dimer (AKD).

[00139] In one embodiment, additives such as pigments, binders and adhesives

N substances are suitable for baked products.

OF

S [00140] In some embodiments, the product or fibrous structure can only comprise

N one fibrous layer. x = 25 — [00141] In some embodiments, the product may comprise 1-20 fibrous layers,

O

2 such as at least two fibrous layers such as at least three fibrous layers. 3

[00142] In some embodiments, the product comprises an intermediate layer, such as a pre-coating layer, between the coating and the fibrous structure.

[00143] The intermediate layer may comprise or consist of MFC, PVA, CMC, starch, talc or combinations thereof.

[00144] The advantage of using an intermediate layer between the coating and the fibrous structure is that the adhesion and functionality of the coating can be improved.

[00145] The present invention makes it possible to achieve a smooth surface in the fiber-rich structure to be coated, which facilitates the application or attachment of the coating, especially the powder-coated layer, to the fiber-rich structure.

[00146] The coating and optional interlayers are typically added after the molding step, preferably after the hot pressing step. — [00147] One or more intermediate layers can be prepared before the hot pressing step, for example already in the molding or casting step.

[00148] In one — embodiment — the coating — is applied — before = any hot pressing step or between two hot pressing steps. During hot pressing, the coating layer thus forms a film, typically a smooth and uniform film, — as a result of the applied heat. Thus, the heat melts the powder coating and transforms it into a film. In this way, it may be possible to produce embossed structures or other textured structures on the open surface of the coating, which typically forms the outermost surface of the product.

[00149] The hot pressing step, which can comprise at least two — hot pressing steps, can produce a smooth outer surface for the final product. Advantageously, all external or exposed surfaces of the final product can become smooth.

N [00150] For example, a first hot pressing step may remove water originating from the molding step, and a subsequent second hot pressing step may produce

N from the applied powder coating of the membrane structure.

I

= 25 [00151] FIG. 1 is a schematic description of a fibrous structure coated according to at least some embodiments of the present invention 3. Structure 3 comprises a first fibrous layer 1, a second fibrous layer 2, and

N between the first fibrous layer 1 and the second fibrous layer 2 of the inner fibrous layer 3. In addition, the structure comprises an intermediate layer 4 and a coating 5 on top of the first fiber-rich layer. In other implementations, the intermediate layer 4 may be missing. In some embodiments, the structure can comprise a second coating (not shown) on the opposite side of the fibrous layers under the second fibrous layer 2. The intermediate layer can be applied between such a second coating and the second fibrous layer 2 in a similar way as between the (first) coating 5 and the first — fibrous layer 1 .

[00152] In another embodiment, the product comprises only one fiber-rich layer, such as the first fiber-rich layer 1, the coating 5, and optionally the intermediate layer 4.

[00153] In yet another embodiment, the product does not contain any intermediate layer. — [00154] In some embodiments, the product does not contain any inner fibrous layers. In other embodiments, the product comprises one, two or three inner fibrous layers between the first fibrous layer 1 and the second fibrous layer 2.

[00155] A multi-layer fibrous structure is advantageously achieved in such a way that — all fibers to be included in the final structure, typically the fibrous structure to be coated, undergo a foam forming process.

[00156] The advantage of foam molding is that a lighter and bulkier product can be produced. In addition, a more homogeneous formation can be achieved. The use of foam enables the easy production of multi-layered fibrous structures — in the batch method, i.e. all the fibrous layers can be molded in the same mold to form a multi-layered stack in the mold, which stack is then hot-pressed. & [00157] Dewatering of the entire fibrous structure in the same mold

The advantage is that the bonding between the layers can be enhanced even during dewatering compared to dewatering the layers one at a time.

E 25 — [00158] In some embodiments, the final product can be foamed layers

S also comprises hydroformed layers as part of the fibrous structure. Like

I water-formed layer or water-formed layers can be formed in a separate process

S and combined with a foam-formed layer or a foam-formed multi-layer > structure by hot pressing. One advantage of hydroforming is that it is easy to manufacture flat or planar structures. In hydroforming methods, the individual fibrous layers are typically molded and removed from the mold independently of each other.

Separate molds can be used. After removal from the mold(s), the fibrous layers can be stacked and connected to each other and/or to other layers by hot pressing.

[00159] In one embodiment, the fiber-rich structure comprises several fiber-rich layers produced by hydroforming methods and connected to each other and optionally in addition to at least one foam-formatted fiber-rich layer to form a fiber-rich structure to be coated.

[00160] In some embodiments, the fibrous structure can be formed solely by hydroforming methods.

[00161] In one embodiment, the fiber-rich structure comprises one or more inner fiber-rich layers produced by a foam molding method.

[00162] In one embodiment, the entire fiber-containing structure is produced by a foam molding method.

[00163] The fibrous structure is preferably a three-dimensional cast multi-layered fibrous structure obtained using a mold comprising at least one three-dimensional non-planar mold surface, wherein said fibrous structure has a three-dimensional shape consistent with the shape of said three-dimensional non-planar mold surface .

[00164] The product can have, for example, the shape of a cup, a plate, a bowl, a pan, — a hinged package or a tray. 2 [00165] The product is typically a food or liquid package or container or food or

N liquid serving product, such as a cup for drinking or a food tray or plate. 3 n [00166] The product can be used to pack food or liquid or drink,

No. for storing, cooking and/or heating. Examples — include a = 25 —frozen food packages intended to be heated, yogurt packages and

O

2 trays for fresh meat or fish. 3

[00167] The product can be used, for example, for packaging various industrial products, such as food products, packaging trays intended for cold meat, fish, cheese and other sliced foods, goods such as food, drink,

for storing and transporting medicines, cosmetics and materials sensitive to moisture and oxygen.

[00168] In some embodiments, the product can be used as a heat-resistant padding material or as a heat-resistant protective material.

[00169] More generally, the product can be used for packing and storing all kinds of oily and/or aqueous products.

[00170] In one example, the product is a package intended for cosmetics.

[00171] In one example, the product is a package intended for medicines.

[00172] The product can be used as packaging for food or liquid or — as a serving product for food or liquid or as a fried product or part thereof.

[00173] Next, we describe — the production of a dry-coated fibrous structure according to some embodiments.

[00174] The method comprises putting into use at least one fibrous composition containing cellulose and/or lignocellulosic fibers and water After that — a coating layer is applied to at least part of the surface of the cast fibrous structure.

Said coating layer is applied using a dry coating method, such as a powder coating method.

[00175] Said molding step preferably comprises molding a three-dimensional fibrous structure from said at least one fibrous composition — using a three-dimensional mold.

S

N [00176] Said powder coating method may comprise a dry composition,

S for example the application of dry powder, such as powder paint <electrostatically

N on the surface of the fibrous structure, and curing or melting the applied powder or

E film formation, preferably by heating.

Oh 2 25 — [00177] A dry composition, such as a thermoformable <t

The application of the Q powder coating composition can be carried out using an electrostatic

O

S using a sprayer or any other suitable means or method, for example using fluidized bed coating or a mini coater.

[00178] A dry composition, such as powder paint, may comprise particles that typically have an average particle size in the range of 2-50 µm.

[00179] In some embodiments, the powder paint has a softening temperature Tg in the range 70-90 *C, a melting temperature in the range 120-180 *C, and it hardens — typically at a temperature of 180-220 *C.

[00180] The coating preferably comprises a thermoformable powder coating, which may only require sufficient heat and time to melt the powder into a smooth, uniform film.

[00181] Properties such as adhesion to metal, lubricity of the coating, flexibility and elongation of the coating and many others can be optimized for a specific application. For thermoforming coatings, the powder can have these properties naturally without the need for additional curing or cross-linking after addition to the part or surface.

[00182] In one embodiment, the dry matter content of the fibrous structure to be coated is at least 60%, such as at least 70%, for example 60-80%.

[00183] In one embodiment, said at least part of the surface to be coated is essentially dry. The top layer of the fibrous structure to be coated can, for example, be substantially dry, such as dried by heating.

[00184] The dry powder applied to said surface may contain pigments and, in addition, — one or more additives that can be selected from the following groups: resins, binders and fillers, such as barite, silica, carbonates, silicates, aluminum hydroxide, latexes, ™

S nylon, polyethylene, polyester, polypropylene and polyvinyl chloride and their mixtures. © L. .

O [00185] In one embodiment, a coating layer is formed on said surface

N by spraying. The present invention can enable the application of a powder powder coating a 25 — directly on a vertical or curved surface by spraying. — . . . . . . . . oh 2 [00186] In some embodiments, the fibrous structure to be coated is placed <t

S in the vicinity of an — object made of — metal material, such as = a sheet of metal foil

O

S during the application of the coating layer. In this way, the fiber-rich structure receives a sufficient electrical charge.

[00187] Other means can be used to form the coating layer, such as preparing the coating film separately with a powder coating method and then attaching or pressing the finished coating film to the desired surface of the molded fibrous structure.

[00188] Curing or fusing or preparing the film may comprise contact or non-contact heating, hot pressing, IR curing or microwave curing or any combination thereof, preferably heating to a temperature of at least 120 *C, for example at least 150 * to C.

[00189] In one example, the film preparation step comprises a first step, — in which the applied dry composition, such as dry powder paint or dry particles, is melted by IR melting and later a second step in which the film is finally cured or prepared with one or more. with the hot pressing step.

[00190] Pressure can be used in curing or melting or film production steps, for example in one or more hot pressing steps. — [00191] In some embodiments, the final coating thickness is less than 100 ins, such as less than 70 µm.

[00192] Next, we describe the implementations related to the foam formation of the fibrous structure in more detail.

[00193] In one embodiment, the fiber-containing structure to be coated or part thereof — is obtained using foam molding. 2 [00194] In some embodiments, a fibrous structure or at least one thereof

N of the fibrous layers can be obtained by a method comprising the following

O steps: fiber-rich sludge containing fibers is introduced; is ground into a fiber-rich one

N sludge fibers and/or barrier substances are added to fibrous sludge; is converted

E 25 — fibrous sludge into a foamed composition; to be molded, as to be molded

S foamed composition in the mold; water is removed; and hot pressed.

S

S [00195] The method initially uses a foamed composition that contains

O

S fibers, water, air and one or more foaming chemicals. The foam can also contain fillers, additives, pigments, binders, stabilizers, barrier dispersions and adhesives.

[00196] The foaming chemical, such as the surfactant used, can be non-ionic, anionic, cationic or amphoteric. A suitable amount of surfactant is approximately 150-1000 ppm based on weight. Examples of anionic surfactants are alpha-olefin sulfonates, and non-ionic surfactants are PEG-6 lauramide. Specific examples — include sodium dodecyl sulfate (SDS), Tween 20, and mixtures thereof. Tween 20 contains at least 40% by weight of lauric acid, with the rest consisting mainly of myristic, palmitic and stearic acids.

[00197] The bubble size (bubble diameter) in the foam is typically about 10-300 µm, for example 20-200 µm, usually about 20-80 µm.

[00198] In one embodiment, a composition suitable for foaming is obtained by mixing a fibrous slurry with a consistency of approximately 0.5-7% by weight (amount of fiber in relation to the weight of the slurry) with a foam that is formed from water and a surfactant and whose air content is approximately 10-90 percent by volume, for example 20-80 percent by volume, such as 50-70 percent by volume, resulting in a foamed — fibrous sludge with a fiber content of about 0.1-3 percent by weight.

[00199] In one embodiment, a molded multilayer fibrous structure is obtained by a method that comprises: molding a molded multilayer foamed structure from at least one foamed fibrous composition that contains cellulose fibers, water, air and a foaming agent and optionally also barrier substances; — removing water from the structure, preferably using vacuum; and hot pressing the dewatered structure to obtain a molded multilayer fibrous structure. At least one of the fibrous 2 layers of the multilayer fibrous structure has barrier properties substantially throughout its structure.

O

OF

© [00200] In the present context, "moulding" (molding) refers to the process of giving the e 25 — foamed composition a shape, such as a three-dimensional shape, in a mold.

E [00201] In a preferred method, a foamed fibrous composition is fed

S shaped. The mold typically comprises a cavity or interior space, which is delimited by the inner surfaces of the mold.

I The fed foamed composition is molded in this cavity.

OF

O

S [00202] The foamed composition may be fed into the mold in an amount of foamed composition, such as to provide a layer of foamed composition on at least one inner surface of the mold. The layer is typically non-planar and can be understood as the thickness of the foamed composition on the inner surface of the mold and conforming to the shape of said surface, such as essentially constant thickness.

[00203] The molding step typically comprises pressing said fibrous composition in the inner space of the mold by bringing the parts of the mold closer to each other.

[00204] The molding step of the multilayer foamed fibrous structure may comprise feeding the first fibrous composition in foamed form into the mold, and molding said first fibrous composition in the mold to produce the first foamed fibrous layer. After this, without removing the first fibrous layer from the mold, the process is continued by feeding — a second fibrous composition in foamed form into the mold and molding said second fibrous composition in the mold to produce a second fibrous layer.

This results in a two-layer molded foamed fibrous structure in the mold.

[00205] Unless otherwise stated, "parts of the mold" refers to those parts of the mold that — delimit the interior space and thus contribute to the shaping of the foamed fibrous composition.

[00206] The second foamed fibrous layer can be fed and will therefore be located either on top of the first foamed fibrous layer or below it in the mold. The mentioned feeding steps can also be carried out in either order: either the first layer or the second layer can be formed first in the mold. < [00207] It can also be formulated that a fiber-rich structure is obtained by using

N separate molds for producing said first and second foamed fibrous layers 3, and the resulting first and second fibrous layers are joined together

N 25 — in the mentioned hot pressing step. i

[00208] In one — embodiment — said — feeding — into the mold — comprises feeding the foamed fibrous composition 3 in a foamed form into the inner space or inner volume of the mold 5, where said inner space is limited by the inner surfaces of the mold.

OF

> [00209] Using negative pressure in the dewatering step is advantageously possible.

[00210] The final multi-layer foamed fibrous structure is removed from the mold by opening the mold.

[00211] Adjusting the distance between the parts of the mold during the feeding and molding of the foamed compositions is advantageously possible.

[00212] Before starting to feed another, for example, another fiber-rich composition into the mold, it is typically necessary to increase the interior space of the mold by moving the parts of the mold farther apart. The volume of the inner space can be reduced or increased in order to shape the already fed foam and, accordingly, to make room for the next fed foam. — [00213] In all mold interior volume adjustments, some parts of the mold may remain stationary while other parts move.

[00214] In one example, one or more parts of the mold remain stationary and one or more other parts of the mold move during said approach or said enlargement.

[00215] The mold can, for example, comprise two partial molds, such as two halves, which are arranged opposite each other and move relative to each other.

Part molds can be brought closer together to form a fibrous structure.

Partial molds can be moved apart from each other to increase the interior space or even further to open the mold and remove the molded fibrous structure from the mold.

[00216] In one example, a fibrous structure can be obtained by using a mold consisting of two parts: a negative mold and a positive mold, which can be arranged opposite to each other to enclose an inner space, also called

N as a molding space or molding cavity between the two parts. The composition to be molded or = to be molded is fed into the molding mode and negative mold and/or positive

N 25 — the molds are brought closer together to give the composition the shape of the molding space

S equivalent form. "Zooming" refers to the process of reducing the interior space of 2 positive and negative molds by moving one or both.

OF

2 [00217] Dewatering of the structure can be carried out by connecting a vacuum to the interior of the mould, which contains the supplied foamed composition (supplied foamed compositions).

[00218] The dewatering step precedes the hot pressing step, which leads to the final fibrous product to be coated, i.e. a fibrous structure in which all layers are connected to each other. In hot pressing, the temperature is typically higher than room temperature, for example at least 50 °C, for example at least 100 °C.

[00219] The molded fibrous structure can be dried, for example, by vacuum, heating, air drying, radio frequency drying or microwave drying or any combination thereof.

[00220] EXAMPLE

[00221] In the following, we describe an embodiment in which the fibrous structure to be coated with a dry coating layer according to some embodiments of the present invention is obtained by foam forming using a mold consisting of two parts, called a pair of molds.

[00222] Any of the features and combinations of features described below can be combined with the embodiments and alternatives described earlier in this application.

[00223] The method — is — intended for the formation of a molded — fibrous — structure. The method creates a layer of foam The layer is part of the final product. The foam, also called a "foamed composition", contains cellulosic = and/or lignocellulosic fibers, water, air, and one or more — foaming chemicals. The foam can also contain, for example, fillers and other normal papermaking chemicals, such as hardeners, additives, pigments, dyes and binders. & ob [00224] The layer is formed with a pair of molds. Molds can consist of several e part molds.

E 25 [00225] In principle, one mold is a negative mold, while the other is a corresponding

S positive mold. In this way, the layer takes on a three-dimensional shape during molding.

I The water and air in the foam must be removed. This is mainly done by reducing the size of the mold

distance between S and causing pressure. The pressure forces air and water out of the foam fed > between the molds. The porous surfaces of the molds (molded product surfaces) provide an outlet for water, foaming chemicals and air, while the fibers are preserved and form a layer.

[00226] The foam can be fed from one mold to another. The molds are at a certain distance from each other, and there is a closed cavity for the foam. In this way, feeding the foam is fast, and the timing can be chosen more freely.

[00227] Foam can also be fed through both molds.

[00228] In this example, the pair consists of an upper mold and a lower mold, and the upper mold is movable while the lower mold is arranged to be stationary. The foam is fed through the lower mold. — [00229] The foam can be fed while the pair is at some distance from each other or while the pair is in motion relative to each other. This shortens the molding cycle. For example, foam can be fed even though the upper mold is moving upwards. On the other hand, the pair can first be moved apart from each other and the feeding of the foam starts only after this.

[00230] Feeding the foam through the mold provides an additional advantage. Now it is possible —to form many layers instead of a single layer using the layering method.

The formed layer can be removed after forming the pair contains. After the layer is formed, the pair can alternatively be moved apart and more foam can be fed for a new layer, and then the pair is brought closer together again. Here, too, foam can be fed even when moving pairs apart from each other. — [00231] In practice, 1-10 additional layers can be formed, preferably 2-4 additional layers. After molding and pressing, air and unbound water are removed and

S

S a semi-finished fiber-rich structure is obtained.

OF

O [00232] The next step is hot pressing to remove the water bound to the fibers.

N The layers finally stick together in the hot pressing phase. Several hot pressing steps

E 25 — can be implemented consecutively. — . . . . . 2 [00233] Surprisingly, after the first layer, an additional layer can be formed <t

S on either side of the first floor. In other words, the foam can

O

S previously feeds the layer to either side. For example, one inner layer can be formed first to act as a body layer, and then one additional layer can be formed on both sides of the inner layer to act as surface layers. There are therefore three layers in total.

[00234] A multi-layer fibrous structure can also be produced in another way. The fiber-rich structure can be combined from multilayer fiber-rich — partial structures obtained from two separate mold pairs. The fibrous partial structures formed from these two pairs can be combined and hot-pressed to obtain a single fibrous structure. For example, one inner layer with one bottom layer can be formed in one pair. At the same time, one inner layer with one upper layer can be formed in the second pair. When these layers are combined, a fibrous structure with four layers is formed.

[00235] The rapid formation of several layers into a single fibrous structure is a great advantage. The foam can be replaced before forming the next layer or layers after the first layer. Foams with different properties can be used to form a single fibrous structure. In this way — the layers can be different from each other. The fibrous structure can include, for example, one or two inner layers formed from one type of foam.

Then there can be at least one outer layer of another type of foam. Foams can therefore change the cross-sectional profile of the fibrous structure.

[00236] The fibrous structure can surprisingly be molded without additional heating. — Because the foam has a low water content and contains a lot of air, water can be removed efficiently and the fibrous structure retains its shape after molding. At the same time, the foam keeps its shape and the energy consumption is low. ™

S [00237] The temperature of the foam is kept in the range of 15-45 *C, preferably in the range of 25-35 *C. If necessary, the foam and/or molds can be cooled to keep the temperature % 25 — stable and low enough.

E [00238] At such low temperatures the fibers still contain some moisture.

S During hot pressing, moisture is removed as water and steam, which also creates a smooth finish

I of the surface and contributes to the internal binding to form a solid layered fibrous = structure.

[00239] Immediately when the pair starts to move apart from each other, foam is fed into the interior of the mold. When the pair is brought closer to each other again, the feeding stops and the water drains away from the pair. At the same time, the air is removed.

[00240] The removal of water and air by compression can be promoted by vacuum.

[00241] Although a single-layer fibrous structure can be formed, the method is advantageous when forming many layers.

[00242] The foam is made of water, air, fibers and a foaming chemical.

The foam contains small fractions or particles of the fibers in question. A foaming chemical is also used to promote foam formation and maintain the shape of the foam. — [00243] The origin and composition of the fibers can vary widely. For example, wood fibers or plant fibers (e.g. straw, sugarcane waste and bamboo fibers) can be used, but artificial cellulose fibers are also possible.

[00244] In proper foam, water and fibers and possible additives are evenly distributed. on the walls of the foam bubbles. The foam is a non-flocculated heterogeneous — fibrous raw material, where the air in the bubbles carries the fibers and other raw materials into the molding process.

When using foam, the retention capacity of the fibers is also very high. In practice, more than 99% of the fibers remain in the fiber-rich structure, which is formed by the thick foam acting as a carrier medium.

[00245] Additives can have different retention properties depending on the purpose of use. 2 [00246] By forming — a fibrous structure from several layers of the structure

N features can be customized in many ways. For example, the basic structure of the fiber structure

O and surface properties can be created with different foam compositions. In practice

N each layer can have its own process parameters and raw materials. For example

E 25 — the rigid frame of the fibrous structure can be formed from cheaper fibers and then

S surface layers of higher quality fibers. Compared to known 3 processes using aqueous fiber slurry, the fiber density is much 2 higher in the foam. At the same time, the amount of water circulating inside the walls of the bubbles is significantly smaller, and removing the water during molding is easy. Foam with small amounts of water enables fast process cycles.

[00247] Changing fractions or types of foam for different layers of the fibrous structure may be possible.

[00248] The foam can be fed quickly enough into the mold space, especially when using vacuum.

[00249] In a proper foam, the bubbles do not separate and the fibers are evenly distributed. During molding, foam is dosed or fed into the interior of the mold between two molds. The volume of the interior of the mold can be adjusted according to the required layer thickness.

[00250] The formation of the next layer can, for example, take place on either side of the previous layer. The feeding of the foam can also start already when moving the pair apart. This is advantageous, because during the moving apart the mold space is immediately filled with foam without air being able to get into this space before the foam.

[00251] The foam is fed through the mold into the interior of the mold. 'The interior space of the mold means — the space between a pair of molds.

[00252] Vacuum can also be used. The negative pressure promotes the removal of water and air. The negative pressure can be used even during the feeding of the foam, but at the latest when starting to bring the pair closer to each other. During molding, the mold space decreases, but not as much as in the actual post-molding — pressing phase. In addition, it is possible to keep the formed layer under vacuum on the surface (inner surface) of the desired mold to form an additional layer on the selected 2 sides of the previous layer. & ob [00253] Molding can be performed without heating to control the optimal foam structure = for uniform formation of the fibrous structure. In practice

N 25 molding is performed at an essentially constant process temperature, preferably 15-45 *C

Between S In addition to the mold pair — this temperature can also be maintained throughout the 3 foam system to ensure optimal bubble size for a high-quality product 5 . In this way, the lifetime of the foam can be extended. Air is also easier

S removes like steam, and the layer remains undamaged and the process stable. — In practice, the foam contains more than 50% air, preferably 55-75% air.

[00254] The bubble size of the optimal foam in molding can be approximately 10-500 µm in diameter, preferably 50-150 µm in diameter.

[00255] The present foam method unexpectedly achieves high consistency and good molding at the same time (compared to known molding methods that use water slurry. The mentioned water-based methods require a longer heating and dewatering time, because the consistency is much lower, and the formation is worse due to flocculation.

[00256] The layered fibrous structure is formed as layers on top of each other. In the dewatering phase, the water is removed from the formed structure through the mold. The layer structure is bound together at the latest during hot pressing.

[00257] The layered fibrous structure can be formed in an optional layer order. In other words, the formation can start from any inner layer or from either surface layer.

[00258] The — binding — of the layers — to each other — can be = initiated = by carrying out — drainage across the interfaces of the layers.

[00259] The bonding of the layers continues or at the latest takes place in the later hot pressing stage, when the heat and steam generated in the fibrous structure and the steam passing through the layers also strengthen the bonding of the layers to each other.

[00260] Layering can be done with the same fibers, but in different layers — different additives can be used. 2 [00261] Hot pressing may = comprise several = separate hot pressing steps.

N Can be applied to hot pressing and/or drying of fibrous structure

O hot air or radiation heating or impulse drying. &

I [00262] After the hot pressing step, an optional additional drying step a = 25 at an elevated temperature can follow. 3 3 [00263] The method involves generating foam from fibers, water, air and a foaming chemical. Foam properties may vary as previously described.

In addition, the method includes the use of a pair of molds whose mutual distance can be changed. In other words, the distance between the molds can be changed. In practice, after feeding the foam, the molds are pressed together to remove water and air, resulting in a fibrous structure.

[00264] Furthermore, the method further includes feeding foam between the molds to form a layer. The fibrous structure may consist of a single layer, but preferably the fibrous structure may contain several layers. Foam can also be fed when the molds are at some distance from each other and also when moving a pair relative to each other. This shortens the process cycle and gives more options for customizing the process and the final product.

[00265] The method includes forming a closed mold space and feeding some amount of foam into the mold space, which is similar to a closed cavity. The molded fibrous structure is removed from the pair and transferred to hot pressing.

[00266] The pair preferably includes an upper mold and a lower mold. The upper mold is movable, while the lower mold is arranged to be stationary, or alternatively, the lower mold is movable, while the upper mold is arranged to be stationary, or alternatively — both molds are movable.

[00267] When the mold space is closed, the molds can be some distance apart from each other during molding. After being moved apart, the pair makes room for additional foam.

[00268] In practice, the distance between the molds is 10-100 mm, preferably 20-80 mm.

In general, the thicker the layer, the greater the distance. Foam flow rate — remains reasonable. In practice, the flow speed is 1-3 meters per second.

[00269] As previously mentioned, several identical fibrous structures can be ™

N can be achieved by a parallel molding method, where each mold of the pair comprises several

N ob identical partial molds or sub-moulds.

O

N [00270] Each partial or sub mold is evenly filled with foam. Molded

E 25 — fibrous structures are therefore of uniform quality, and the process is fast. — e e . . . . . 2 [00271] When the mold space has been filled with foam, water and air are removed by pressing. <t

S Water and air can penetrate through the surface of the mold, while the fibers accumulate

O

S for mold surface. Dewatering can be promoted by negative pressure. Drainage can also be promoted by the overpressure caused by the opposing mold.

[00272] It should be noted that the presented embodiments of the invention are not limited to the specific structures, method steps or materials presented here, but are extended to their counterparts in a manner understood by ordinary professionals in the relevant fields. It should also be noted that the terminology used herein is used to describe certain embodiments only and is not intended to be limiting.

[00273] Reference throughout this explanation to "one embodiment" or "one embodiment" means that a certain feature, structure or feature described in connection with the embodiment is included in at least one embodiment of the present invention. Accordingly, occurrences of the expressions "in one embodiment" or "an embodiment" in various places throughout this specification may not all refer to the same embodiment.

[00274] As used herein, several titles, structural elements, compositional elements and/or materials may be presented in a common list for clarity. However, these lists must be interpreted as identifying each member of the list as a separate and unique member. Thus, no single member of such a list — may be construed as de facto equivalent to any other member of the same list simply because they have appeared in a common group without reference to the contrary. In addition, various implementation forms and examples of the present invention can be referred to here together with alternatives regarding its various components. It is understood that such embodiments, examples and — alternatives should not be considered as de facto equivalents of each other, but should be considered as separate and independent representatives of the present invention.

[00275] Described features, structures or properties can also be combined in any suitable way in one or more embodiments. The following & explanation presents numerous specific details, such as examples of lengths, > 25 — widths, — shapes, etc. for a thorough understanding | to obtain — from the invention = implementation forms. However, a person skilled in the art understands that the invention can be done

N implements in practice without or using one or more specific details

E other methods, components, materials, etc. Well-known structures, 3 materials or functions are not in other cases shown or described 5 30 — in detail to avoid obscuring aspects of the invention. 5 [00276] Although the above examples are illustrative of the principles of the present invention in one or more specific applications, it is obvious to professionals in the field that numerous changes to the form, use and implementation details can be made without practicing inventiveness and without deviating from the principles and concepts of the invention.

Thus, the invention is not intended to be restrictive other than as described in the protective claims presented below.

[00277] The verbs "comprise" and "comprise" are used in this document as open-ended limitations that neither exclude nor require the existence of unstated features. The properties presented in the independent protection claims can be freely combined with each other, unless otherwise specifically stated. Furthermore, it should be understood that the use of the singular throughout this document does not exclude the plural.

INDUSTRIAL APPLICABILITY

[00278] The present invention is industrially applicable at least in the manufacture of powder-coated molded fiber products.

REFERENCE NUMBERS

1 first fiber-rich layer 2 second fiber-rich layer 3 fiber-rich inner layer 4 intermediate layer 5 coating

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Claims (23)

PROTECTION REQUIREMENTS: 1. A product comprising: — a fibrous structure comprising cellulosic and/or lignocellulosic fiber material and obtained by a casting process; and — the coating (5), such as at least one coating layer, on at least one surface of the fibrous structure, characterized by the fact that: — the coating is obtained by a dry coating method, preferably a powder coating method, the density of the fibrous structure to be coated in said dry coating method is greater than 500 kg/m", calculated as dry as the weight of the substances per volume, and the dry square weight of the product is in the range 5 — 900 g/m". 2. A product according to claim 1, wherein the coating forms the top layer or the bottom layer of the product. 3. A product according to one of the aforementioned protection requirements, wherein the product comprises at least two coating layers located on different surfaces of the fibrous structure, — such as on opposite sides of a planar fibrous structure. 4. A product according to one of the aforementioned protection requirements, wherein the product additionally comprises a non-fibrous intermediate layer (4) between the said coating and the fibrous structure. S 25 N © 5. A product according to one of the aforementioned protection requirements, where the coating is applied to the curved or non-horizontal surface of the % fibrous structure. x > 6. A product according to one of the aforementioned protection requirements, where the coating is a non-S 30 — fibrous coating and comprises or consists of thermoplastic polymer material or S thermoplastic polymer material, such as polyolefin, polyester, PET, > polyhydroxyalkanoate or polylactic acid. 7. A product according to one of the aforementioned protection requirements, wherein the coating comprises a non-fibrous layer, which comprises or consists of a biodegradable thermoplastic polymer material. 8 A product according to one of the aforementioned protection requirements, wherein the coating comprises at least 50% by weight, such as at least 80% by weight, such as at least 90% by weight of thermoplastic polymer material or thermoplastic polymer material. 9. A product according to any of the above protection claims, wherein the coating is — a functional coating adapted to change the functional properties of the surface, such as barrier properties, visual properties, functional properties and/or haptic properties. 10. A product according to claim 9, when the coating or a part of it is adapted to increase — the barrier properties of the surface of the fibrous structure, and the barrier properties include one or more of the following: oil and grease resistance, liquid resistance, water resistance, water vapor resistance, aroma resistance, gas resistance, oxygen resistance, aroma barrier. — 11. A product according to any of the aforementioned protection requirements, wherein the coating is adapted to change the surface hardness, microscopic roughness, macroscopic roughness, friction properties, contact properties or color of the fibrous structure. OF 12. A product according to one of the aforementioned protection requirements, when the dry S 25 — square weight of the product is in the range of 100 — 800 g/m”, such as in the range of 200 — 600 g/m”. 3 @ 13. A product according to one of the aforementioned protection requirements, when the dry I square weight of the coating is in the range 2 — 80 g/m?, for example 10 — 35 g/m?. a > 2 30 — 14. A product according to one of the aforementioned protection requirements, wherein the coating thickness N is at least 1 um, such as in the range 2 — 50 um, for example 5 — 30 um. N >” 15. A product according to any of the aforementioned protection requirements, wherein the fibrous structure is essentially free of plastic materials and resin. 16. A product according to one of the aforementioned protective claims, wherein the fibrous structure is a multi-layered fibrous structure and comprises at least a first fibrous layer (1) and a second fibrous layer (2), each of which comprises cellulose and/or lignocellulose fiber material. 17. A product according to any of the above-mentioned protective claims, further comprising between the first and second fibrous layers one or more fibrous inner layers (3), each of which comprises cellulose and/or lignocellulosic fiber material, — preferably comprising a mechanical pulp such as CTMP or BCTMP and/or wreckage. 18. A product according to one of the aforementioned protection requirements, wherein the cellulose and/or lignocellulosic fiber material comprises one or more of the following: bleached or unbleached chemical pulp, semi-chemical pulp, mechanical pulp, — thermomechanical pulp, chemithermomechanical pulp, bleached chemithermomechanical pulp, recycled cellulose and/ or lignocellulosic fibres, fibrillated cellulose such as microfibrillated cellulose or nanofibrillated cellulose, nanocellulose, pulp, cellulosic by-products, regenerated cellulose fibres, and any other cellulosic material comprising cellulose fibers or parts of cellulose fibres, — originating from any perennial or annual plants. 19. A product according to one of the aforementioned protection requirements, wherein the fibrous structure comprises at least 50% by weight of cellulose and/or lignocellulosic fiber material N calculated from the total dry matter. S 25 © 20. A product according to one of the aforementioned protection requirements, where one or more % of the fibrous layers or the entire fibrous structure has been obtained by foam forming, z water forming, dip forming, vacuum forming, > compression forming, thermoforming or dry forming or any combination of these S 30 —. OS I 21. A product according to any of the above claims, wherein the fibrous structure is a three-dimensional molded fibrous structure obtained using a mold comprising at least one three-dimensional, non-planar mold surface, wherein said fibrous structure exhibits a three-dimensional shape consistent with said three-dimensional, non - with a flat mold surface. 22. A product according to any of the above-mentioned claims, wherein the product or part thereof has an overall shape adapted to hold a liquid or a flowing material, such as the overall shape of a cup or bowl. 23. A product according to one of the aforementioned protection requirements, when the fibrous structure to be coated or its part has been obtained using foam molding. S N O N © ? S N I a a O O O <t O N O N >”