Fibre article and method for the manufacture thereof

Abstract

The present invention concerns a fibre article, comprising: cellulosic and / or lignocellulosic fibres, and fibres comprising a thermoplastic polymer, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 – 30 wt-%, calculated from the dry weight of the fibre article, wherein the average density of the fibre article is less than 1200 kg / m3, wherein the fibre article has a thickness in the range of 1 – 100 mm, wherein the fibre article has been obtained by a method comprising heat-treating a fibre structure comprising the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer in a temperature above the melting point of the thermoplastic polymer, wherein the heat treatment comprises contact heating the fibre structure on or against a mould.

Description

FIBRE ARTICLE AND METHOD FOR THE MANUFACTURE THEREOFFIELD

[0001] The present invention belongs to the field of material technology. More specifically, it relates to the field of thermoformable materials.BACKGROUND

[0002] Light-weighting is required in multiple fields as a way to reduce environmental impact and logistics costs, as well as add convenience to consumer. Current light-weighting solutions and products are typically based on fossil-based materials, mainly plastic, or require advanced technologies, such as 3D printing.

[0003] Construction industry utilizes sawn timber, plywood and expanded polystyrene as mould material in concrete-casting. Mould materials create a lot of waste, which often ends up in incineration. In addition, forming these mould materials into curved shapes is challenging.

[0004] Recycling of fibre-containing composite materials in the plastics recycling stream is not possible. This creates a challenge for biocomposites (consisting for instance 20-30% fibres) recycling and limits the end of life options.SUMMARY OF THE INVENTION

[0005] The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.

[0006] According to a first aspect of the present invention, there is provided a fibre article, comprising: cellulosic and / or lignocellulosic fibres, and fibres comprising a thermoplastic polymer, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the average density of the fibre article is less than 1200 kg / m3, wherein the fibre article has a thickness in the range of 1 - 100 mm, wherein the fibre article has been obtained by a method comprising heat-treating a fibre structure comprising the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer in a temperatureabove the melting point of the thermoplastic polymer, wherein the heat treatment comprises contact heating the fibre structure on or against a mould.

[0007] According to a second aspect of the present invention, there is provided use of the fibre article according to the first aspect in furniture, sport equipment, garments, vehicle interiors, vehicle parts, packaging materials, consumer goods, construction materials, or panels.

[0008] According to a third aspect of the present invention, there is provided a method for the manufacture of a fibre article, the method comprising the steps of: providing cellulosic and / or lignocellulosic fibres, mixing the cellulosic and / or lignocellulosic fibres with fibres comprising a thermoplastic polymer, forming the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer into a fibre structure with a density within the range of 20-90 kg / m3, by means of an air-laid process, heat-treating the fibre structure in one or more stages in a temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer together and, optionally, to shape the fibre structure, wherein at least one of the stages comprises contact heating on or against a mould; whereby the fibre article is obtained, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the fibre article has a thickness in the range of 1 - 100 mm.

[0009] According to a fourth aspect of the present invention, there is provided a fibre article obtainable by the method according to the third aspect.

[0010] Various embodiments of the first aspect, the second aspect, the third aspect and / or the fourth aspect may comprise one or more features from the following bulleted list:• The heat treatment comprises thermoforming the fibre structure in a substantially dry state on or against a mould into a pre-determined three-dimensional shape.• The fibre article comprises an embossed surface structure obtained by the thermoforming.• The average density of the fibre article is in the range of 100 - 1100 kg / m3, such as 200 - 1000 kg / m3, such as 600 - 900 kg / m3.• The fibre article exhibits density variation or a density gradient.• At least a part of the fibre article has a non-planar shape, such as a curved shape.• The overall shape of the fibre article is non-planar.• The cellulosic and / or lignocellulosic fibres are selected from bleached or unbleached chemical pulp, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp, mechanical pulp, such as chemi- thermomechanical pulp (CTMP) or bleached chemi-thermomechanical pulp (BCTMP), recycled pulp, non-wood pulp, sawdust, regenerated fibres such as viscose, or any combination thereof• The cellulosic and / or lignocellulosic fibres comprise paper-grade pulp.• The cellulosic and / or lignocellulosic fibres are substantially debonded to each other, such as non-homified.• The debonding has been achieved by treating the fibres mechanically and / or chemically.• Before said heat-treating: the cellulosic and / or lignocellulosic fibres have been treated by dry-milling, such as hammer-milling, and preferably processed by an airlaid method.• The fibres comprising a thermoplastic polymer comprise bicomponent fibres.• The thermoplastic polymer is selected from the following group: polyesters, such as polybutylene terephthalate and polyethylene terephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof.• The amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 25 wt-%, such as 2 - 20 wt-%, calculated from the dry weight of the fibre article.• The fibre article comprises cellulosic and / or lignocellulosic fibres in an amount of at least 60 wt-%, such as at least 65 wt-%, such as at least 75 wt-% or at least 80 wt-%, calculated from the total dry weight of the fibre article.• The fibre article comprises additive chemicals selected from binding agents, barrier agents, flame-retardants, surfactants, mould inhibitors, odour suppressing agents, blowing agents, lightweight fillers, bulk improvement agents, pigments, reinforcement fibres such as glass fiber, or combinations thereof.• The fibre article comprises a coating layer on at least one surface.• The coating layer comprises a plastic material, a metal material such as aluminium film, or a paper-based material.• The bending strength of the fibre article is in the range of 0.8 to 50 N / mm2.• The tensile strength of the fibre article is in the range of 0.4 to 15 N / mm2.The perpendicular tensile strength of the fibre article is in the range of 0.02 to 1.0 N / mm2.• The surface roughness Ra of the fibre article is less than 15 pm, such as less than 10 pm, such as less than 7 pm.• The surface roughness Rq of the fibre article is less than 15 pm, such as less than 10 pm, such as less than 8.5 pm.• The surface roughness Rz of the fibre article is less than 50 pm, such as less than 45 pm, such as less than 40 pm.• The length-weighted average fibre length the cellulosic and / or lignocellulosic fibres is at least 0.5 mm.• The step of providing cellulosic and / or lignocellulosic fibres comprises dry-milling, such as hammer-milling, the cellulosic and / or lignocellulosic material.• Said mixing is carried out in dry state.• During said heat-treatment at least a part of the thermoplastic polymer melts, whereby the fibres of cellulosic and / or lignocellulosic material and the fibres comprising a thermoplastic polymer become bonded to each other.• The heat treatment comprises thermoforming.• Said thermoforming comprises contact heating and shaping on or against a mould to a pre-determined shape.• The heat-treatment comprises hot-pressing, for example contact heating in combination with pressing, the fibre structure on or against a mould.• The pressing is carried out at a pressure of 2 to 20 bar / cm2, such as 5 to 15 bar / cm2.• The heat-treatment comprises: in a first stage, heat-treating the fibre structure, preferably by radiation heating, in a first temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising the thermoplastic polymer together to obtain a planar fibre structure, and thereafter in a second stage, thermoforming the planar fibre structure on or against a mould in a second temperature above the melting point of the thermoplastic polymer, to obtain the fibre article.• Said first temperature is less than 220 °C, such as 60 to 220 °C.• Said second temperature is equal to or lower than the first temperature.• Said heat treatment comprises, after the second stage, a third stage comprising hot- pressing an embossed surface structure onto at least one surface of the fibre article.• The mould comprises at least one surface which is configured to contact the fibre structure to limit the shape of the fibre structure during said heat-treatment.• The mould comprises an inner moulding space which is defined by at least one planar surface, such as two opposite planar surfaces.• The mould comprises an inner moulding space which is defined by at least one non- planar surface.• The fibre structure to be heat-treated is in the form of a slab or a sheet which may be single-layered or multi-layered.• The fibre structure to be heat-treated is multi-layered and comprises at least two airlaid fibre layers, wherein each fibre layer comprises, independently from each other, a mixture of cellulosic and / or lignocellulosic fibres and fibres comprising a thermoplastic polymer.• The length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is reduced by less than 20%, such as by less than 10%, as a result of the drymilling step.

[0011] Advantages

[0012] The invention here is a pulp fibre-based lightweighting solution. It has the potential to be recycled with paperboard recycling. It expands the application space of pulp fibres into new areas, e.g., furniture. The method is simple and versatile, using existing woodworking and plastic processing machinery and technologies.

[0013] One advantage of the present invention is that the use of fossil-based materials can be significantly reduced by the inclusion of biobased fibres, i.e., cellulosic and / or lignocellulosic fibres. A further interrelated advantage of replacing such fossil-based materials with biobased fibres is that the material simultaneously acts as a long-time carbon storage.

[0014] Another advantage of the invention is that the composition and density of the material can be easily altered for different applications. Further versatility is achieved by combining the material of the invention in a layered structure, in particular such that adjacent layers have different properties.

[0015] Another advantage of the present invention is that the material can be recycled in both standalone form and in layered form, for example, in a paperboard recycling process.

[0016] The invention reduces the need to employ fossil-based materials.EMBODIMENTS

[0017] In the present context, the term “fibrous cellulosic material” or “cellulosic fibres” typically refers to cellulosic and / or lignocellulosic fibres. Such fibres may be of plant origin.

[0018] In the present context, the term “mould” may refer to a means configured to contact the fibre structure and thereby to guide and / or limit the shape of the fibre structure, for example during said heat-treatment.

[0019] Within the present disclosure, the term “cellulosic material” may refer to both or either of cellulosic and lignocellulosic materials. In some embodiments, the fibrous cellulosic and / or lignocellulosic material may be selected from bleached or unbleached chemical pulp, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp, or sawdust. In some preferred embodiments, the fibrous cellulosic and / or lignocellulosic material may be selected from chemical pulp, mechanical pulp, for example chemi-thermomechanical pulp (CTMP) or bleached chemi- thermomechanical pulp (BCTMP), or non-wood pulp. In other embodiments, the fibres comprise semi-chemical pulp, thermomechanical pulp, or recycled pulp. In some embodiments, the pulp may be made from any broad-leaved tree such as a tree from the betulaceae family, for example birch or aspen, from the salicaceae family, from eucalyptus, mixed tropical hardwood or pines or from any combination of the aforementioned. The pulp may be also made from any conifer such as spruce or pine or from any combination thereof. The pulp may also be made from a combination of broad-leaved trees and conifers. In another embodiment, the pulp may be made from any annuals such as straw, common reed, reed canary grass, bamboo, sugarcane, bagasse or any grass plant.

[0020] In the present context, the term “compression recovery” refers to a material’s capability to revert into its initial shape after compression. It can be expressed as a percentage of the initial thickness of the material, i.e., the thickness the material reverts to after compression into a predetermined thickness, such as compression into 50 % of the initial thickness of the material.

[0021] Light- weighting is a way to improve efficiency in automotive and transportation, and comfort in handheld and wearable objects. The invention described hereis a method to further process low density fibre slabs or sheets into curved 3D shapes, and the use of low density fibre slab or sheet as a curved 3D shape. It enables the use of pulp fibre based materials for light- weighting.

[0022] The present fibre articles are produced by air-laid technology and heat treatment. The fibre articles obtainable include stand-alone 3D structures or multilayered sandwich-type structures.

[0023] In embodiments, the present fibre article exhibits pleasant tactile properties, i.e. properties perceptible by touch. For example, the surface of the fibre article may feel soft, hairy, furry and / or textile-like. Preferably the surface of the fibre article does not feel rough. Such pleasant tactile properties may be a result of a high concentration of cellulosic fibres in the fibre article, particularly on its surface, and the looseness or debonded nature of the fibres. An efficient way to improve looseness of the fibres is to treat the fibres by hammer-milling before processing the fibres by an air-laid process.

[0024] Pleasant tactile properties may be achieved by ensuring that fibre length of the cellulosic and / or lignocellulosic fibres is not compromised, such as substantially reduced, during hammer-milling. Preferably, the length-weighted average fibre length is at least 0.5 mm in the end product, the fibre article.

[0025] In an aspect, the present invention provides a fibre article, comprising:- cellulosic and / or lignocellulosic fibres, and- fibres comprising a thermoplastic polymer, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the average density of the fibre article is less than 1200 kg / m3, wherein the fibre article has a thickness in the range of 1 - 100 mm, wherein the fibre article has been obtained by a method comprising heat-treating a fibre structure comprising the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer in a temperature above the melting point of the thermoplastic polymer, wherein the heat treatment comprises contact heating the fibre structure on or against a mould.

[0026] In embodiments, at least a part of the fibre article has a non-planar shape, such as a curved shape.

[0027] In embodiments, the overall shape of the fibre article is non-planar.

[0028] In another aspect, the present invention provides a method for the manufacture of a fibre article, the method comprising the steps of:- providing cellulosic and / or lignocellulosic fibres,- mixing the cellulosic and / or lignocellulosic fibres with fibres comprising a thermoplastic polymer,- forming the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer into a fibre structure with a density within the range of 20-90 kg / m3, by means of an air-laid process,- heat-treating the fibre structure in one or more stages in a temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer together and, optionally, to shape the fibre structure, wherein at least one of the stages comprises contact heating on or against a mould; whereby the fibre article is obtained, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the fibre article has a thickness in the range of 1 - 100 mm.

[0029] In some embodiments, the fibre article comprises cellulosic and / or lignocellulosic fibres in an amount of at least 55 wt-%, such as at least 70 wt-%, for example at least 75 wt-%, at least 80 wt-%, at least 85 wt-% or at least 90 wt-%, calculated from the dry weight of the fibre article. In preferred embodiments, the fibre article may comprise, for example, 85 wt-%, 90 wt-%, 95 wt-% or 98 wt-% of the fibrous cellulosic and / or lignocellulosic fibres calculated from the dry weight of the article.

[0030] The term “additive” may herein refer to all kind of components added to the fibre article, and may include, for example, chemical substances or alternative materials, such as fillers. Such additives may be included in the fibre article to, for example, improve the hydrophobicity or flame-resistance of the material, or to prevent bacterial growth.

[0031] In embodiments, the fibre article may comprise additive chemicals selected from binding agents, barrier agents, flame-retardants, surfactants, mould inhibitors, odour suppressing agents, blowing agents, lightweight fillers, bulk improvement agents, pigments, reinforcement fibres such as glass fiber, or combinations thereof

[0032] In embodiments, the fibre article comprises cellulosic and / or lignocellulosic fibres in an amount of at least 60 wt-%, such as at least 65 wt-%, such as at least 75 wt-% or at least 80 wt-%, calculated from the total dry weight of the fibre article.

[0033] A high content of cellulosic and / or lignocellulosic fibres in the fibre article is advantageous as it reduces the environmental impact of the product when compared to fossilbased materials. The inclusion of cellulosic and / or lignocellulosic fibres in the above amounts also enhances the recyclability and biodegradability properties of the material, as at least half of the dry weight of the material thus is recyclable and / or biodegradable.

[0034] In embodiments, the average density of the fibre article is less than 1200 kg / m3.

[0035] In embodiments, the average density of the fibre article is in the range of 100- 1100 kg / m3, such as 200 - 1000 kg / m3, such as 600 - 900 kg / m3.

[0036] In embodiments, the average density of the fibre article is in the range of 100 - 700 kg / m3, such as 200 - 650 kg / m3.

[0037] In embodiments, the average density of the obtained fibre article is less than 850 kg / m3, such as 20 to 850 kg / m3.

[0038] In embodiments, the average density of the obtained fibre article is less than 700 kg / m3, such as less than 680 kg / m3.

[0039] In embodiments, the fibre article exhibits density variation or a density gradient. The density variation may also involve variation in the thickness of the fibre article. The thickness variation can be regular or irregular.

[0040] In embodiments, the fibre article has a thickness in the range of 1 - 100 mm.

[0041] The mechanical properties are dependent on a combination of the thickness and density of the layer. In some embodiments, the thickness may be from 5 mm, 10 mm, 15 mm, 20 mm or 35 mm up to 70 mm, 80 mm, 90 mm.

[0042] In further embodiments of the present disclosure, the fibres of cellulosic and / or lignocellulosic material are selected from bleached or unbleached chemical pulp, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp, mechanical pulp, such as chemi-thermomechanical pulp (CTMP) or bleached chemi-thermomechanical pulp (BCTMP), recycled pulp, non-wood pulp, sawdust, regenerated fibres such as viscose, or any combinations thereof. Such cellulosic and / or lignocellulosic materials can be provided as paper grade pulp, such as kraft pulp.

[0043] Preferably, the cellulosic and lignocellulosic material is a wood-derived material, even more preferably wood derived pulp. Being renewable, wood derived materials are a sustainable alternative to fossil-based materials.

[0044] In embodiments, the cellulosic and / or lignocellulosic fibres are substantially debonded to each other, such as non-homified.

[0045] In embodiments, the debonding has been achieved by treating the fibres mechanically and / or chemically.

[0046] The fibre length of the fibrous cellulosic material may in one example be larger than 0.5 mm, in another example less than 10 mm, such as 0.5 to 5 mm, for example 1 to 5 mm, or 1-2.5 mm.

[0047] The term “fibre length” refers to the distance measured along the longest dimension of the fibre.

[0048] In some embodiments, the length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is at least 0.5 mm, such as at least 1 mm, such as at least 2 mm.

[0049] In some embodiments, the length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is less than 10 mm, such as up to 5 mm, such as up to 2.5 mm.

[0050] A binding composition is a composition that allows the cellulosic and / or lignocellulosic fibres in the fibre article to bind or connect to each other, either directly by forming intra-fibre chemical bonds or by fibre interaction via the binding composition. For example, the binding composition may comprise a binding polymer. The binding polymer may comprise for example a polyester, such as polybutylene terephthalate and polyethyleneterephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof. Preferably, the binding agent comprises bio-based polymers, such as polylactic acid. In preferred embodiments, the binding polymer is a thermoplastic polymer. This allows for at least partial melting of the binding composition, or a thermoplastic polymer thereof, after formation of the fibre structure.

[0051] The binder composition may be provided for example in the form of fibres, pellets of various shapes (spherical, cylindrical, oval etc.), randomly shaped particles, uniformly shaped particles or in the form of a powder. The binding composition may thus simultaneously act as a filler. When included in the form of fibres or particles, the fibre length or the particle size of the binding composition is preferably in the same range or smaller than the fibres of the cellulosic and / or lignocellulosic material. Thus, the fibre average length or the particle average size, referring to the length of the fibre or the crosssection of a particle in its longest direction, is preferably in a range of 0.001 mm- 10 mm, such as 0.02 to 5 mm, for example 1 to 5 mm, or 1-2.5 mm. In particular for pellets or powders, the average cross-section (diameter) of the particles may be in the lower range of this interval, such as from 0.001-2 mm, for example, 0.01-1 mm.

[0052] Binder compositions or additives can be applied in dry form, such as dry fibres, pellets, or powders. The binder composition can be added to the cellulosic and / or lignocellulosic fibres before or during the manufacture of the material, such as during formation of the fibre network. Preferably, the three-dimensional fibre network comprises less than 20 wt-%, less than 15 wt-%, or even more preferably less than 10 wt-% or less than 5 wt-% of binder composition or binder additive, calculated from the dry weight of the three- dimensional network of cellulosic and / or lignocellulosic fibres.

[0053] The binding composition or at least part of the binding composition may be formulated to melt upon heating. Preferably the melting point of such binding compositions is less than 250 °C, such as less than 220 °C, such as less than 200 °C, such as less than 150 °C, or in the range 60 to 220 °C.

[0054] The present fibre article comprises fibres comprising a thermoplastic polymer.

[0055] In embodiments, the thermoplastic polymer is selected from the following group: polyesters, such as polybutylene terephthalate and polyethylene terephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof.

[0056] In embodiments, the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 25 wt-%, such as 2 - 20 wt-%, calculated from the dry weight of the fibre article.

[0057] In embodiments, the fibres comprising a thermoplastic polymer comprise bicomponent fibres.

[0058] In embodiments, the fibres comprising a thermoplastic polymer comprise bicomponent fibres selected from synthetic bicomponent fibres, thermoplastic bicomponent fibres, biobased bicomponent fibres and any combinations thereof.

[0059] The bicomponent fibres may comprise biobased bicomponent fibres.

[0060] Such bicomponent fibres can function as binding composition within the fibre article. Furthermore, bicomponent fibres may act as binding agent between any adjacent layers in the fibre article.

[0061] A bicomponent fibre is a fibre that combines two separate components, i.e., a first component and a second component, into a single filament. The components may be, for example, two separate polymers or a polymer in combination with a naturally derived component, such as a cellulosic material. The two components may be arranged in bicomponent fibres in various ways, for example side-by-side, as a sheath-core structure, as a segmented structure or as a so-called islands-in-the-sea -structure, where one component surrounds several separate sections of the other component. Preferably, the two components are polymers with different properties.

[0062] The first component may comprise a different polymer than the second component. In some embodiments, the molecular weight of the first component differs from the molecular weight of the second component. The polymers of the first component and the second component may be selected from polyesters, such as polybutylene terephthalate and polyethylene terephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof. In some embodiments, both components comprise, independently from each other, a thermoplastic polymer. In some embodiments, the first component comprises cellulose and the second component comprises a thermoplastic polymer. Bicomponent fibres comprising thermoplastic polymer is herein to be understood as bicomponent fibres wherein at least one of the components comprises thermoplastic polymer.

[0063] In some embodiments, the bicomponent fibre has a sheath-core structure. A sheath-core structure refers to a structure wherein the polymer(s) used in the core-component are completely surrounded by sheath-component(s). The sheath-component may in some examples comprise a different polymer than the core-component. In other embodiments, the molecular weight of the sheath-component differs from the molecular weight of the corecomponent. The polymers for the sheath-component and the core-component may be selected from polyesters, such as polybutylene terephthalate and polyethylene terephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof. In some preferred embodiments, the sheath-component is a thermoplastic polymer. The core component may comprise cellulose. In some embodiments, the core component may comprise a thermoplastic polymer.

[0064] The fibre article may comprise a bicomponent fibre having a sheath-core structure, such as a bicomponent fibre in which the core component comprises cellulose and the sheath component comprises a thermoplastic polymer.

[0065] The melting point of at least one component of the bicomponent fibre may be less than 250 °C, such as less than 220 °C, such as less than 200 °C, such as less than 150 °C, or in the range 60 to 220 °C. In some preferred embodiments where the bicomponent fibres have a sheath-core structure, the melting point of the sheath-component is lower than the melting point of the core-component. Preferably, the differences between the melting point of the sheath-component and the melting point of the core-component enables melting of the sheath-component while the core-component remains in solid form. The melted sheath-component may provide for inter-fibre connections within the fibre article, while the core component remains intact and provides structural support.

[0066] It is possible to use any bicomponent fibre arrangements that provide a similar effect in which one component of the bicomponent fibre melts, connecting the cellulosic fibres together, and the other component remains intact, providing structural support to the formed fibre article.

[0067] In embodiments, the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 25 wt-%, such as 2 - 20 wt-%, calculated from the dry weight of the fibre article.

[0068] The fibre article may comprise from 2 wt-%, 3 wt-%, 5 wt-% or 10 wt-% and up to 12 wt-%, 15 wt-%, 25 wt-%, 40 wt-% or 50 wt-% of bicomponent fibres calculated from the dry weight of the fibre article, for example, 2 to 20 wt-%, such as 5 to 15 wt-%, or 3 to 10 wt-%, of bicomponent fibres calculated from the dry weight of the fibre article.

[0069] In some embodiments, the length-weighted average fibre length of the fibres comprising a thermoplastic polymer is at least 0.5 mm, such as at least 1 mm, such as at least 2 mm.

[0070] In some embodiments, the length-weighted average fibre length of the fibres comprising a thermoplastic polymer is less than 10 mm, such as up to 5 mm, such as up to 2.5 mm.

[0071] In further embodiments, the fibre article may comprise a binding composition which is an expandable binding composition, such as expandable microspheres. The expansion may be activated thermally or chemically. Preferably the binding composition comprises thermally expandable components, such as thermally expandable microspheres. Such thermally expandable components can have a sheath-core structure, preferably such that the sheath structure comprises thermoplastic polymers. The core structure typically comprises hydrocarbons with low boiling points.

[0072] In further preferred embodiments, the cellulosic and / or lignocellulosic fibres comprise modified cellulosic and / or lignocellulosic fibres. The fibres can be mechanically or chemically modified fibres of cellulosic material, such as structurally modified fibres, non-derivatized modified fibres, or derivatized modified fibres. The fibres can, for example be treated mechanically, such as by grinding. Such modified cellulosic and / or lignocellulosic fibres may also include fully or partially regenerated fibres. Alternatively, or additionally, the fibre modification may include use of a compatibilizer, a cross-linking agent, alkali treatment, acid treatment, solvent treatment, or activation or reaction through chemically charged regions, such as cationization or anionization, without being limited thereto. Examples of modified cellulosic fibres that may be included for functionality are viscose fibres and micro- or nanofibrillated cellulose.

[0073] In a preferred embodiment, the chemically treated fibres are non-derivatized cellulosic and / or lignocellulosic fibres treated with deep-eutectic solvent (DES).

[0074] A further example of solvent treatment is treatment with alkali, such as sodium hydroxide (NaOH).

[0075] In some embodiments, the barrier agent may include hydrophobic agents, polymeric barriers, sizing agents, coated fibres, and barrier resins. Such barrier agents may form a barrier on individual fibres or fibre bundles of cellulosic material, or on the fibre article. Herein, barrier agents are also interpreted as to include agents providing the fibres with chemical barrier properties, such as water or grease resistance, i.e., without the formation of physical barriers. Thus, the barrier agents may include hydrophobic agents, such as organosilanes, betulin, and betulinic acid, or sizes, such as styrene acrylate copolymers (SA), polyurethanes, alkylated urethanes, carboxymethylcellulose and its salts, alkyl celluloses, such as methyl cellulose and ethyl cellulose, styrene / maleic acid copolymer (SMA), di-isobutylene / maleic anhydride, aery lonitrile / acry late copolymers, a rosin, a wax, such as alkyl ketene dimer (AKD) or paraffin wax, an oil, such as alkenyl succinic anhydride (ASA), or styrene acrylate emulsion (SAE).

[0076] In some embodiments, the fibre article may comprise at least one flame retardant, which may be selected from the following group: minerals, organohalogen compounds, organophosphorus compounds, inorganic phosphorus compounds, and organic compounds, and combinations thereof. Such a flame retardant may be comprised within the three-dimensional fibre network or in any additional layers of the material.

[0077] Examples of mineral flame-retardants include: aluminium trihydroxide (ATH), magnesium hydroxide (MDH), huntite and hydromagnesite, various hydrates, red phosphorus, and boron compounds, mostly borates.

[0078] Examples of inorganic phosphorus flame-retardants include ammonium polyphosphate (APP) and melamine polyphosphate (MPP).

[0079] Examples of organic flame-retardants include carboxylic acid and dicarboxylic acids.

[0080] In some embodiments, mould inhibitors may be added to the fibre article for improved antibacterial properties. Such antimicrobial properties may be derived from fibre treatment or the inclusion of mould inhibitors, such as, propionic acid and salts thereof, sorbic acid and salts thereof, methyl fumarate, and p-hydroxybenzoate compounds.

[0081] Coating layer

[0082] In embodiments, the fibre article comprises a coating layer on at least one surface, wherein the coating layer comprises a plastic material, a metal material such as aluminium film, or a paper-based material.

[0083] The coating layer may comprise, for example, woven fabrics or non-woven fabrics made of natural or synthetic fibres.

[0084] Preferably, the thickness of the coating layer is less than 5 mm or less than 3 mm, such as ranging from 0.1 to 2 mm, for example ranging from 0.2 to 1 mm or from 0.3 to 0.5 mm. In one embodiment, the thickness of the coating layer is 0.1 to 0.4 mm. The advantage of having such a coating layer is that it may provide structural strength, for example by protecting the fibre article from being defibrillated during handling, or may serve as a functional component providing, for example, water repellent properties to the fibre article, or binding properties between layers.

[0085] Preferably, the amount of such additives is below 40 wt-%, as calculated from the total dry weight of the fibrous cellulosic and / or lignocellulosic material, such as below 30 wt-% below 20 wt-% or below 10 wt-% of the total dry weight of the fibrous cellulosic and / or lignocellulosic material.

[0086] In some embodiments, the additive chemical may be mixed to the fibrous cellulosic and / or lignocellulosic material prior to forming the fibre structure, such as by pretreatment of fibres or by mixing the fibres with additives. In other embodiments, the additive may be applied to the fibre structure after forming such a fibre structure. Application after forming the fibre structure may in some embodiments comprise spraying the additive onto the surface of the fibre network.

[0087] In an aspect of the present invention, the fibre article is multilayer fibre article comprising two or more fibrous layers, such as 2-10 fibrous layers or 2-6 fibrous layers,

[0088] Such layers may be identical in composition and / or density. The layers may be of identical or different thickness. Layers of different properties, such as different composition, density and / or thickness, may be arranged within the multilayer fibre article in a symmetrical or asymmetrical manner.

[0089] Different composition herein refers to both chemical and physical composition. The physical composition may be different in respect of at least one of the fibre structure, the fibre length, the fibre composition, or the type of cellulosic material, named as a few examples. The chemical composition can be different in relation to any additives or functionalisation agents used, such as the amount of binder or the type of fibre modification used. By different composition is also meant different types of material, such as synthetic materials and biobased materials.

[0090] The fibre structure may in some embodiments be formed into a form of a sheet or a slab. Preferably the “sheet” or the “slab” has two opposite planar surfaces which are generally orientated in parallel.

[0091] In some embodiments, there is a substantially uniform distribution of the cellulosic fibres throughout the fibre article.

[0092] In embodiments, the bending strength of the fibre article is in the range of 0.8 to 50 N / mm2.

[0093] In embodiments, the tensile strength of the fibre article is in the range of 0.4 to 15 N / mm2.

[0094] In embodiments, the perpendicular tensile strength of the fibre article is in the range of 0.02 to 1.0 N / mm2.

[0095] In an aspect, the invention provides use of the fibre article in furniture, sport equipment, garments, vehicle interiors, vehicle parts, packaging materials, consumer goods, construction materials, or panels.

[0096] Manufacturing method

[0097] In an aspect, the invention provides a method for the manufacture of a fibre article, the method comprising the steps of: providing cellulosic and / or lignocellulosic fibres, mixing the cellulosic and / or lignocellulosic fibres with fibres comprising a thermoplastic polymer,- forming the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer into a fibre structure with a density within the range of 20-90 kg / m3, by means of an air-laid process,- heat-treating the fibre structure in one or more stages in a temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer together and, optionally, to shape the fibre structure, wherein at least one of the stages comprises contact heating on or against a mould; whereby the fibre article is obtained, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the fibre article has a thickness in the range of 1 - 100 mm.

[0098] In the above method, some of the steps may be performed simultaneously. In particular, the steps of mixing and forming may be carried out simultaneously.

[0099] The fibre structure obtained in the forming step may comprise or consist of a three-dimensional fibre network.

[0100] The fibre structure may be in the shape of a sheet, mat or slab. Such a shape is advantageous in the subsequent heat-treatment step.

[0101] The forming of the fibre structure may be carried out on any suitable substrate, such as on a wire or on a mould.

[0102] When formed on a wire, the radiation heating stage may be carried out when the fibres lay on the wire.

[0103] When formed on a mould, the radiation heating stage and the thermoforming stage may both be carried out on the mould. Alternatively, when formed on a mould, the separate radiation heating stage may be omitted, and the contact heating stage may lead to binding of the fibres, obtaining the fibre structure, and re-shaping the fibre structure to obtain the end product, the fibre article.

[0104] In the present method, an air-laid process is used for forming the fibre structure.

[0105] Advantages of using an air-laid process are that the obtained fibre structure is easy to handle, shows homogeneous fibre distribution, and can be directly obtained in a desired thickness. Air-laying processes also allow for uniform inclusion of dry state additives.

[0106] In preferred embodiments of the invention, the fibres of cellulosic and / or lignocellulosic material are selected from bleached or unbleached chemical pulp, such as bleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp, mechanical pulp, such as chemi-thermomechanical pulp (CTMP) or bleached chemi-thermomechanical pulp (BCTMP), recycled pulp, non-wood pulp, sawdust, or any combinations thereof. Pulp is a readily available, fully biodegradable and cost-efficient material that is easy to transport. In some embodiments, the fibre structure is formed from dry fibres.

[0107] A preferred cellulosic material is paper grade pulp, i.e., pulp suitable for use in paper and / or cardboard manufacture. For example, baled pulp or fluff pulp may be used as the cellulosic material, preferably baled pulp.

[0108] In embodiments, the step of providing cellulosic and / or lignocellulosic fibres comprises dry-milling, such as hammer-milling, the cellulosic and / or lignocellulosic material.

[0109] In some embodiments of the invention, the step of providing cellulosic and / or lignocellulosic fibres comprises dry-milling the cellulosic and / or lignocellulosic material. The inclusion of a dry-milling step, such as a hammer-milling step, in the method provides for a finely separated fibre matrix, which therefore is well suited for the formation of low- density fibre structures as disclosed herein. This pre-processing step is especially preferable when using air-laying techniques in the formation of the three-dimensional fibre network.

[0110] Preferably, before said heat-treating: the cellulosic and / or lignocellulosic fibres have been treated by dry-milling, such as hammer-milling, and processed by an airlaid method.

[0111] In some embodiments, the length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is reduced by less than 20%, such as by less than 10%, such as by less than 5% as a result of the hammer-milling step.

[0112] For example, before the hammer-milling step, the length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is at least 0.5 mm, such as at least 1 mm, such as at least 2 mm.

[0113] For example, after the hammer-milling step, the length-weighted average fibre length of the cellulosic and / or lignocellulosic fibres is at least 0.4 mm, such as at least 0.5 mm, such as at least 1 mm, such as at least 1.5 mm.

[0114] An advantage of maintaining a sufficient fibre length is that the surface of the fibre article can be provided with pleasant tactile properties, such as softness and smoothness.

[0115] In embodiments, said mixing is carried out in dry state.

[0116] The mixing step may comprise mixing the cellulosic and / or lignocellulosic fibres with the additives in dry state.

[0117] The dry state additive can be premixed with dry state lignocellulosic and / or cellulosic fibres prior to formation of the fibre structure. Alternatively, or additionally, the additive may be applied during the formation of the fibre structure. For example, the addition of dry state additive may be an integrated part of an air-laying process where the additive is mixed with dry pulp fibres prior to settling on a substrate, typically a wire.

[0118] Heat treatment

[0119] In embodiments, the fibre structure to be heat-treated is in the form of a slab or a sheet which may be single-layered or multi-layered. The slab or sheet is obtained in the forming step by the air-laid process.

[0120] In embodiments, the fibre structure to be heat-treated is multi-layered and comprises at least two air-laid fibre layers, wherein each fibre layer comprises, independently from each other, a mixture of cellulosic and / or lignocellulosic fibres and fibres comprising a thermoplastic polymer.

[0121] In embodiments, the heat treatment comprises thermoforming the fibre structure in a substantially dry state on or against a mould into a pre-determined three- dimensional shape.

[0122] The method comprises one or more heat treatment stages in which the temperature is raised above the melting point of the thermoplastic polymer.

[0123] The purpose of the heat treatment of the fibre structure may be to bind the fibres to each other and to induce a change in the shape and / or density of the fibre structure.

[0124] At least one of the heat treatment stages involves contact heating the fibre structure in order to re-shape the fibre structure, to obtain the end product, which is a fibre article with a desired three-dimensional shape.

[0125] In embodiments, during said heat-treatment at least a part of the thermoplastic polymer melts, whereby the fibres of cellulosic and / or lignocellulosic material and the fibres comprising a thermoplastic polymer become bonded to each other.

[0126] In embodiments, the heat treatment comprises thermoforming, wherein said thermoforming comprises contact heating and shaping on or against a mould to a predetermined shape.

[0127] In embodiments, the heat-treatment comprises hot-pressing, for example contact heating in combination with pressing, the fibre structure on or against a mould.

[0128] In embodiments, the pressing is carried out at a pressure of 2 to 20 bar / cm2, such as 5 to 15 bar / cm2.

[0129] In embodiments, the heat-treatment comprises:- in a first stage, heat-treating the fibre structure, preferably by radiation heating, in a first temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising the thermoplastic polymer together to obtain a planar fibre structure, and thereafter- in a second stage, thermoforming the planar fibre structure on or against a mould in a second temperature above the melting point of the thermoplastic polymer, to obtain the fibre article.

[0130] The radiation heating stage may also involve melting and / or activating of any additives applied. The radiation heating may comprise heating in an oven.

[0131] When thermally reactive additives, such as additives comprising thermoplastic polymers or expandable microspheres, are included in the fibre structure, the radiationheating treatment can be carried out at a temperature above the melting point or activation point of the additive, such as temperatures up to 250 °C, up to 220 °C, up to 200 °C, up to 150 °C, or in the range 60 to 220 °C. Such a radiation heating stage may be carried out by methods known in the art, for example by heating in an oven.

[0132] The thermoforming stage involves contact heating of the fibre structure and leads to re-shaping of the fibre structure.

[0133] In embodiments, said first temperature is less than 220 °C, such as 60 to 220 °C.

[0134] In embodiments, said second temperature is equal to or lower than the first temperature.

[0135] The fibre article may comprise an embossed surface structure obtained by the thermoforming.

[0136] In embodiments, said heat treatment comprises, after the second stage, a third stage comprising hot-pressing an embossed surface structure onto at least one surface of the fibre article.

[0137] In embodiments, the mould comprises at least one surface which is configured to contact the fibre structure to limit the shape of the fibre structure during said heattreatment.

[0138] In embodiments, the mould comprises an inner moulding space which is defined by at least one planar surface, such as two opposite planar surfaces.

[0139] In embodiments, the mould comprises an inner moulding space which is defined by at least one, such as two non-planar surface.

[0140] In some embodiments of the present disclosure, the step of providing fibres of cellulosic and / or lignocellulosic material comprises chemical and / or physical modification of the fibres of cellulosic and / or lignocellulosic material. Such chemical and / or physical modification can include processes known int the art, in particular any fibre modification as disclosed herein, such as mechanical grinding, cross-linking, solvent treatment, regeneration, or modification through chemical charges, or any combination thereof.

[0141] As discussed above, air-laying techniques allows for the formation of a uniform fibre network. Furthermore, when using air-laying techniques, bicomponent fibres or other additives in dry state may be combined with the cellulosic and / or lignocellulosic fibres upon formation of the air-laid fibre network. In this manner, no separate mixing is required, as the cellulosic and / or lignocellulosic fibres, the fibres comprising the thermoplastic polymer and eventual other additives may be contacted with each other upon web formation, i.e., by supplying the fibres and the additive from different containers to the air-laying process. This also allow for uniform inclusion of the additive in the fibre network, and in particular with respect to bicomponent fibres and / or polymer fibres it allows for such fibres to be arranged within the network in a similar manner as the cellulosic material. Such a uniform fibre distribution provides for even mechanical properties across the entire fibre network. Air-laying technology can be used in the formation of three-dimensional fibre structures in thickness ranges as disclosed herein.

[0142] In a preferred embodiment of the method of the present disclosure, the fibres of cellulosic and / or lignocellulosic material are paper grade pulp fibres, preferably provided as baled pulp. The preferred embodiment further comprises dry-milling the pulp fibres, feeding the dry-milled pulp fibres, the fibres comprising the thermoplastic polymer and an optional dry state additive to an air-laying process, preferably from separate feed sources, forming a three-dimensional air-laid fibre network, and subjecting the three-dimensional fibre network to the heat-treatment step involving contact heating.

[0143] Paper grade pulp fibres herein refers to pulp fibres suitable for paper and / or cardboard manufacture, in particular any commercial pulp to be used in such processes. The inclusion of a dry-milling step, in particular a hammer-milling step, provides for a finely separated pulp matrix, that is well suited for air-laying. By obtaining a pulp matrix having a high degree of disintegrated, individual fibres provides for a uniform fibre distribution within the air-laid material. It also provides for the possibility to include dry bicomponent fibres and optional dry state additives, in particular provided from separate feed sources as described above. Dry state additives can thus be fed directly to the air-laying process, without any preliminary blending of the cellulosic fibres and additive. Thus, an even quality fibre network can be obtained in a simplified process, using currently available equipment without the need for retrofitting.

[0144] In some preferred embodiments, the present fibre article may be produced by thermoforming as follows:

[0145] In an embodiment, a low density fibre structure can be heated in a mould without pressing. Density of the material remains in the original range, for example 40-80 kg / m3. Alternatively, only light hot-pressing (calendaring) of the low density fibre structure may be applied to create a density gradient.

[0146] In an embodiment, a low density fibre structure can be hot-pressed into varying shapes, thereby creating a stiff fibre article, for example a planar or curved board with a density 200-400 kg / m3.

[0147] In an embodiment, sandwich-structured multilayered fibre articles with a plastic coating layer as an outer layer can be produced by hot-pressing. Glue is not needed for attaching the layers to each other.

[0148] It is to be understood that individual method steps as disclosed herein can be exchanged or combined with further steps. For example, any mechanical treatment, such as hammer milling or grinding, can be applied or exchanged with similar processing steps for producing a fibre matrix with a higher content of disintegrated, individualised fibres. The three-dimensional fibre network formed in the method as presented above, or any embodiment thereof, may also undergo further processing steps post formation, for example in connection with the heat treatment stages or thereafter. The fibre-network may, for example be coated, spray treated, moisture balanced, consolidated, etc. The surface of the formed fibre structure can, for example be treated such that it is non-planar, thus comprising regular or irregular patterns, which may be provided, for example, for improved airflow (breathability) of the material. Such patterns may comprise, for example, grooves or knobs. The patterns may be produced by use of pressing techniques and / or heat treatment.

[0149] Examples

[0150] In the following, non-limiting examples of the present disclosure are presented.The examples are only intended to illustrate the properties and functionality of the material of the present disclosure, without being restricted thereto. Thus, any method steps and compositions as presented herein can be combined with other features of the present disclosure.

[0151] Example 1 - Formation of air-laid three-dimensional fibre network

[0152] Fibre structures, i.e. three-dimensional fibre networks, were prepared according to the present disclosure at different densities using the same composition and the same formation technique (air-laying).

[0153] The fibre structure was prepared from pulp fibres (Metsa Pine). The paper grade pulp fibres were provided in the form of pulp bales and hammer-milled prior to being subjected to an air-laying process for the formation of a three-dimensional fibre network.

[0154] Bicomponent fibres comprising biobased polyethylene (Bio-PE) and recycled polyethylene terephthalate (PET) were provided. The bicomponent fibres were blended with the hammer-milled pulp fibres in the air-laying process.

[0155] The pulp fibres and the bicomponent fibres were supplied to the process from different sources and thus blended in the airspace prior to being settled into a three- dimensional fibre network. Thus, no pre-blending of the fibres was needed. The bicomponent fibres of Bio-PE and recycled PET were included in the three-dimensional fibre network in a total amount of 15 wt-%, calculated based on the dry weight of the fibre network. The air-laying process was carried out such that the thickness of the obtained mat was around 50 mm. The air-laid fibre network was subjected to thermal treatment at a temperature of 150 °C by radiation heating.

[0156] The obtained fibre structure was a resilient and durable layer, having an uniform fibre distribution.

[0157] Example 2: Strength properties of thermoformed fibre articles

[0158] Three sample fibre articles (boards) were manufactured.

[0159] First, a fibre structure in the form of a slab was manufactured by an air-laid process. The thickness of the fibre structure was 50 mm. The density of the fibre structure was 40 kg / m3. The fibre structure comprised:- hammer-milled dry bleached softwood pulp (Metsa Fibre Pine) in an amount of 76 wt-%, calculated from the dry weight of the fibre structure,- bicomponent fibres (core-sheath type, Primaloft Biobico by FiberPartner) in an amount of 14 wt-%, calculated from the dry weight of the fibre structure, and- a fire retardant (APP111 by Technosintensi) in an amount of 10 wt-%, calculated from the dry weight of the fibre structure.

[0160] Then, the fibre structures (slabs) were thermoformed to obtain fibre articles having the shape of a planar board. During the thermoforming, the fibre structure was compressed and re-shaped (densified) with a pressure of 15 bar / cm2. The temperature was135 °C. The compression time was 7 minutes.Sample board 1 : thickness 3-4 mmSample board 2: thickness 5 mmSample board 3: thickness 10 mm. Reference board: hardboard (HDF), thickness 3 mm

[0161] The strength properties of the boards were determined. The results are provided in Table 1.Table 1: Results.

[0162] It was observed that mechanical properties could be adjusted by controlling the pressing applied on the slabs during the thermoforming step.

[0163] Example 3 : Surface roughness of thermoformed fibre article

[0164] Surface roughness of Sample board 1 of Example 2 was analysed. The profilometer Mitutoyo SJ-210 (compliant with ISO- 1997) was used. The stylus was dragged across the surface of the sample and moved vertically over the peaks and valleys of the surface. Changes in the stylus height were detected and converted into electrical signals, which were processed to create a surface profile of the sample. From this profile different roughness parameters (Ra, Rq, Rz) were calculated. Ra refers to Arithmetic Average Roughness, commonly used for general quality control and aesthetic surfaces. Rq refers to Root Mean Square Roughness, providing a more sensitive measure of surface roughness compared to Ra, as it emphasizes larger deviations. Rz refers to Average Maximum Height of the Profile, which is particularly useful for assessing surfaces where peak-to-valley variations are critical, such as sealing surfaces.

[0165] The surface roughness results are shown in Table 2.Table 2: Surface roughness results for Sample board 1.

[0166] It is to be understood that the disclosed embodiments are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0167] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment”in various places throughout this specification are not necessarily all referring to the same embodiment.

[0168] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0169] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0170] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0171] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.

[0172] Unless otherwise stated herein or clear from the context, any percentages referred to herein are expressed as percent by weight based on a total weight of the respective composition.

Claims

CLAIMS1. A fibre article, comprising:- cellulosic and / or lignocellulosic fibres, and- fibres comprising a thermoplastic polymer, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the average density of the fibre article is less than 1200 kg / m3, wherein the fibre article has a thickness in the range of 1 - 100 mm, wherein the fibre article has been obtained by a method comprising heat-treating a fibre structure comprising the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer in a temperature above the melting point of the thermoplastic polymer, wherein the heat treatment comprises contact heating the fibre structure on or against a mould.

2. The fibre article according to claim 1, wherein the heat treatment comprises thermoforming the fibre structure in a substantially dry state on or against a mould into a pre-determined three-dimensional shape.

3. The fibre article according to any of the preceding claims wherein the fibre article comprises an embossed surface structure obtained by the thermoforming.

4. The fibre article according to any of the preceding claims, wherein the average density of the fibre article is in the range of 100 - 1100 kg / m3, such as 200 - 1000 kg / m3, such as 600 - 900 kg / m3.

5. The fibre article according to any of the preceding claims wherein the fibre article exhibits density variation or a density gradient.

6. The fibre article according to any of the preceding claims, wherein at least a part of the fibre article has a non-planar shape, such as a curved shape.

7. The fibre article according to any of the preceding claims, wherein the overall shape of the fibre article is non-planar.

8. The fibre article according to any of the preceding claims, wherein the cellulosic and / or lignocellulosic fibres are selected from bleached or unbleached chemical pulp, such asbleached or unbleached softwood chemical pulp and / or bleached or unbleached hardwood chemical pulp, mechanical pulp, such as chemi-thermomechanical pulp (CTMP) or bleached chemi-thermomechanical pulp (BCTMP), recycled pulp, non-wood pulp, sawdust, regenerated fibres such as viscose, or any combination thereof.

9. The fibre article according to any of the preceding claims, wherein the cellulosic and / or lignocellulosic fibres comprise paper-grade pulp.

10. The fibre article according to any of the preceding claims, wherein the cellulosic and / or lignocellulosic fibres are substantially debonded to each other, such as non-homified.

11. The fibre article according to any of the preceding claims, wherein the debonding has been achieved by treating the fibres mechanically and / or chemically.

12. The fibre article according to any of the preceding claims, wherein before said heat- treating: the cellulosic and / or lignocellulosic fibres have been treated by dry-milling, such as hammer-milling, and processed by an air-laid method.

13. The fibre article according to any of the preceding claims, wherein the fibres comprising a thermoplastic polymer comprise bicomponent fibres.

14. The fibre article according to any of the preceding claims, wherein the thermoplastic polymer is selected from the following group: polyesters, such as polybutylene terephthalate and polyethylene terephthalate, polylactic acid, polyethylene, polypropylene or combinations thereof.

15. The fibre article according to any of the preceding claims wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 25 wt-%, such as 2 - 20 wt- %, calculated from the dry weight of the fibre article.

16. The fibre article according to any of the preceding claims, comprising cellulosic and / or lignocellulosic fibres in an amount of at least 60 wt-%, such as at least 65 wt-%, such as at least 75 wt-% or at least 80 wt-%, calculated from the total dry weight of the fibre article.

17. The fibre article according to any of the preceding claims, comprising additive chemicals selected from binding agents, barrier agents, flame-retardants, surfactants, mould inhibitors,odour suppressing agents, blowing agents, lightweight fillers, bulk improvement agents, pigments, reinforcement fibres such as glass fiber, or combinations thereof.

18. The fibre article according to any of the preceding claims, wherein the fibre article comprises a coating layer on at least one surface, wherein the coating layer comprises a plastic material, a metal material such as aluminium film, or a paper-based material.

19. The fibre article according to any of the preceding claims wherein the bending strength of the fibre article is in the range of 0.8 to 50 N / mm2.

20. The fibre article according to any of the preceding claims wherein the tensile strength of the fibre article is in the range of 0.4 to 15 N / mm2.

21. The fibre article according to any of the preceding claims wherein the perpendicular tensile strength of the fibre article is in the range of 0.02 to 1.0 N / mm2.

22. The fibre article according to any of the preceding claims wherein the surface roughness Rq of the fibre article is less than 15 pm, such as less than 10 pm, such as less than 8.5 pm.

23. The fibre article according to any of the preceding claims wherein the length- weighted average fibre length the cellulosic and / or lignocellulosic fibres is at least 0.5 mm.

24. Use of the fibre article according to any of the preceding claims in furniture, sport equipment, garments, vehicle interiors, vehicle parts, packaging materials, consumer goods, construction materials, or panels.

25. A method for the manufacture of a fibre article, the method comprising the steps of:- providing cellulosic and / or lignocellulosic fibres,- mixing the cellulosic and / or lignocellulosic fibres with fibres comprising a thermoplastic polymer,- forming the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer into a fibre structure with a density within the range of 20-90 kg / m3, by means of an air-laid process,- heat-treating the fibre structure in one or more stages in a temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising a thermoplastic polymer together and, optionally, to shape the fibre structure, wherein at least one of the stagescomprises contact heating on or against a mould; whereby the fibre article is obtained, wherein the amount of the fibres comprising a thermoplastic polymer is in the range of 1 - 30 wt-%, calculated from the dry weight of the fibre article, wherein the fibre article has a thickness in the range of 1 - 100 mm.

26. The method according to claim 25, wherein the step of providing cellulosic and / or lignocellulosic fibres comprises dry-milling, such as hammer-milling, the cellulosic and / or lignocellulosic material.

27. The method according to any of claims 25 to 26, wherein said mixing is carried out in dry state.

28. The method according to any of claims 25 to 27, wherein during said heat-treatment at least a part of the thermoplastic polymer melts, whereby the fibres of cellulosic and / or lignocellulosic material and the fibres comprising a thermoplastic polymer become bonded to each other.

29. The method according to any of claims 25 to 28, wherein the heat treatment comprises thermoforming, wherein said thermoforming comprises contact heating and shaping on or against a mould to a pre-determined shape.

30. The method according to any of claims 25 to 29 wherein the heat-treatment comprises hot-pressing, for example contact heating in combination with pressing, the fibre structure on or against a mould.

31. The method according to any of claims 25 to 30 wherein the pressing is carried out at a pressure of 2 to 20 bar / cm2, such as 5 to 15 bar / cm2.

32. The method according to any of claims 25 to 31 wherein the heat-treatment comprises:- in a first stage, heat-treating the fibre structure, preferably by radiation heating, in a first temperature above the melting point of the thermoplastic polymer, to bond the cellulosic and / or lignocellulosic fibres and the fibres comprising the thermoplastic polymer together to obtain a planar fibre structure, and thereafter- in a second stage, thermoforming the planar fibre structure on or against a mould in a second temperature above the melting point of the thermoplastic polymer, to obtain the fibre article.

33. The method according to any of claims 25 to 32 wherein said first temperature is less than 220 °C, such as 60 to 220 °C.

34. The method according to any of claims 25 to 33 wherein said second temperature is equal to or lower than the first temperature.

35. The method according to any of claims 25 to 34 wherein said heat treatment comprises, after the second stage, a third stage comprising hot-pressing an embossed surface structure onto at least one surface of the fibre article.

36. The method according to any of claims 25 to 35 wherein the mould comprises at least one surface which is configured to contact the fibre structure to limit the shape of the fibre structure during said heat-treatment.

37. The method according to any of claims 25 to 36 wherein the mould comprises an inner moulding space which is defined by at least one planar surface, such as two opposite planar surfaces.

38. The method according to any of claims 25 to 37 wherein the mould comprises an inner moulding space which is defined by at least one non-planar surface.

39. The method according to any of claims 25 to 38, wherein the fibre structure to be heat- treated is in the form of a slab or a sheet which may be single-layered or multi-layered.

40. The method according to any of claims 25 to 39, wherein the fibre structure to be heat- treated is multi-layered and comprises at least two air-laid fibre layers, wherein each fibre layer comprises, independently from each other, a mixture of cellulosic and / or lignocellulosic fibres and fibres comprising a thermoplastic polymer.

41. The method according to any of claims 25 to 40, wherein the length- weighted average fibre length of the cellulosic and / or lignocellulosic fibres is reduced by less than 20%, such as by less than 10%, as a result of the dry-milling step.

42. A fibre article obtainable by the method according to any of claims 25 to 41.