Surface covering

Abstract

A method (10) of forming a sheet material, for use as a surface covering, comprises (11) providing a powder material; (12) adjusting water content of the powder material; (13) admixing the powder material to a binder matrix; (14) blending the powder material and the binder matrix 5 to create a sheet material composition; (16) providing a carrier surface; (17) applying the sheet material composition to the carrier surface; (18) spreading the sheet material across at least a portion of the carrier surface to provide a sheet layer; and (21) allowing the sheet material composition to dry to form a sheet. The carrier surface may be flat or contoured. The powder material may be ground coffee or other material. The method allows a thin, large area surface10 covering of around 1 to 3 mm thickness to be made.

Description

[0001] Surface covering

[0002] Field of the Invention

[0003] The present invention relates to a surface cover, such as a prefabricated cover sheet material suitable as wall cover or decorative cover. More specifically, the invention relates to a material sheet and method of forming a profiled sheet that can be manufactured to a length of 2 to 3 metres or more, or to provide smaller panels or wall tiles, in the form of a sheet sufficiently self- supporting for manual handling in a practical setting, so as to be suitable as an internal wall surface cover.

[0004] Background

[0005] Prefabricated cover panels or wallpaper sheets are used as cladding and for decorative purposes for interior design and decoration of walls and sometimes ceilings, floors, or furniture surfaces. To cover relatively large areas, typical approaches include the use of tiles or rigid panels, which require installation, alignment and fixation, or the use of flexible sheets such as wallpaper.

[0006] The application or installation of such coverings can require specialist knowledge and skill to ensure good alignment particularly when covering larger areas such as a wall from ceiling to floor.

[0007] The applicant has developed compositions for use in such surface coverings that incorporate powder materials into a binder matrix, for instance the use of a stone powder to provide a stone effect finish appearance. However, it was found that some materials are not readily compatible to be incorporated into such coverings.

[0008] The present invention seeks to provide a further manufacturing methods suited for a wider range of materials.

[0009] Summary of the Invention

[0010] In accordance with a first aspect of the invention, there is method of forming a sheet material suitable as a surface covering, as defined by claim 1. The method comprises: providing a powder material; adjusting water content of the powder material; admixing the powder material to a binder matrix; blending the powder material and the binder matrix to create a sheet material composition; providing a carrier surface; applying the sheet material composition to the carrier surface; spreading the sheet material across at least a portion of the carrier surface to provide a sheet layer; and allowing the sheet material composition to set to form a sheet.

[0011] The sheet material may be a component used as a surface covering of sheet form, or of thin panel form. Herein, the expression “sheet” may encompass a flexible panel or a pliable panel. In accordance with embodiments, the surface covering is a solid material made from a pliable or flexible material composition such as latex, rubber or the like, having a sheet thickness of typically no more than a few millimetres. As such, the surface covering may be sufficiently pliable or flexible, e.g., so as to be provided in roll form, and so as to allow it to be applied to a surface by unrolling.

[0012] During the blending step, the sheet material composition is preferably blended and / or agitated until it is of a consistency that is sufficiently thick for spreading it onto a surface.

[0013] The powder material may comprise, or may be constituted by, natural waste products in powder or granule form, collectively referenced herein as “powder material”, such as coffee, tea dust, leaves, pine needles, food waste, and other natural (organic matter) materials. The powder may comprise a mixture of different materials and a range of different particle sizes and particle shapes. The material may have low solubility in the binder matrix material.

[0014] In some embodiments, the powder material comprises ground coffee. In some embodiments, the powder material comprises a blend of different types of ground coffee. In some embodiments, the powder material comprises coffee grounds.

[0015] The powder material may be provided by, or comprise, used coffee grounds. The sheet material composition may be formed in the manner of a suspension, comprising coffee powder suspended in a matrix binder material. The powder may be provided in the form of ground material. Specifically, the ground material may be made from fresh or used coffee, including waste coffee materials, such as grounds or dust.

[0016] The method may comprise sifting the powder to achieve a desired particle size distribution.

[0017] In some embodiments, the binder matrix is provided by a polymeric material.

[0018] The binder matrix may be a non-woven material to provide a fluid or pourable composition suitable for spreading onto a surface when mixed with the powder.

[0019] In some embodiments, the binder matrix comprises an aqueous dispersion binder material. A number of suitable binder compositions will be known to a skilled person. The binder may be a water-based material of a type in which the powder material may be dispersed, and which can be dried to form a solid, pliable or rollable sheet.

[0020] In some embodiments, the binder matrix is provided by a material composition comprising one or more constituents from a group including latex, rubber, caoutchouc, or combinations thereof.

[0021] The binder matrix is preferable a binder material providing a matrix for the powder material. Prior to the admixture of a powder, the binder matrix is preferably colourless, transparent or of a light colour, or could be white. However, this is not necessarily the case in all embodiments. It is preferable for the binder matrix material to be able to dry out without extensive shrinking, curling or cracking. In trials, it has been found that latex and latex based compositions are suitable binder matrix materials. Other suitable materials may include rubber, caoutchouc, and similar materials, as well as water-based binders.

[0022] In some embodiments, providing the powder material comprises grinding a precursor material.

[0023] In some embodiments, providing the powder material comprises sifting a precursor material.

[0024] Grinding and / or sifting may be carried out to achieve a desired degree of homogeneity, for instance for the powder to appear uniform under visual inspection. Alternatively, the grinding and / or sifting may be carried out such that powder has a lower degree of homogeneity or be of heterogeneous nature so as to appear textured under visual inspection. The precursor material may be a heterogeneous form of the powder material, e.g. constituted by different batches of coffee grounds.

[0025] In some embodiments, adjusting the water content of the powder material comprises drying the powder material.

[0026] In some embodiments, adjusting the water content of the powder material comprises adding water the powder material.

[0027] For instance, a portion of the powder material may be sprinkled with water, or soaked in water.

[0028] The method may comprise maintaining the powder at a temperature suitable for mixing with the binder matrix. The method may comprise soaking the powder to facilitate mixing it with the binder matrix. In some embodiments, the method comprises adjusting the water content of the powder material to between 5% and 30% w / w.

[0029] In some embodiments, blending the powder material and the binder matrix comprises homogenising the sheet material composition.

[0030] The blending may be carried out to achieve a desired degree of homogeneity. For instance, the blending maybe carried out until gas bubbles are removed or the number of gas bubbles has been reduced to a desired level. The blending may be carried out until pockets of powder have been broken up or the number of powder pockets has been reduced to a desired level.

[0031] In some embodiments, the carrier surface is provided by a backing layer.

[0032] The backing layer may comprise a mesh or fibre-based composition. A suitable backing layer may provide a support for a non-woven sheet material composition. The backing layer may be of woven form, of pressed fibre form, or other suitable network structures. The backing layer may be a composite fibre material, such as a mesh, fleece or felt. The fibre-based composition may be a fibre-reinforced polymer, including carbon, glass, and other types of fibre compositions. However, this is not necessarily a requirement in all embodiments of the invention.

[0033] The backing layer may be partially or fully embedded in the sheet material.

[0034] It is preferable for the backing layer to have material properties that complement or otherwise support the sheet. By complementing, it is meant that the backing layer provides a property that is not present, or not present to the same extent, in the sheet. For instance, the backing layer may comprise an adhesive layer for affixing the sheet via the backing layer to a surface. The backing layer may comprise sound damping or antifungal properties. The backing layer may have a particular fire rating. Several different forms of suitable backing layers will be known to a skilled person.

[0035] In some embodiments, the method comprises spreading the sheet material evenly across at least a portion of the carrier surface to provide a sheet layer of even thickness.

[0036] In some embodiments, the method comprises leaving a free surface of the sheet layer exposed.

[0037] In this manner, the free surface is allowed to air-dry. After a sufficiently long drying time on the carrier surface, the sheet may be sufficiently consolidated to allow it to be manipulated for transfer to a drying rack. In this manner, a surface on which the sheet material was spread out can be freed for reuse.

[0038] In accordance with a second aspect of the invention, there is method of forming a surface covering suitable for attachment to a surface. The method comprises: preparing a sheet material composition of liquid or pourable form using a powder and a carrier matrix; mixing the powder with the carrier matrix to form the sheet material composition; providing a mould shaped to form a sheet material; introducing the sheet material composition into the mould; applying a backing layer to the sheet material composition in the mould; allowing the sheet material composition to set to form a sheet; and demoulding the sheet to provide the surface covering.

[0039] The surface covering may be a sheet material as defined in relation to the first aspect, comprising a sheet thickness of no more than a few millimetres, and pliable or flexible so as to be provided in roll form, and so as to allow it to be applied to a surface by unrolling.

[0040] The surface covering is considered to be a component that is suitable for attachment to a surface underneath in that it is sufficiently self-supporting so as to be suitable for handling during decorating, e.g., rolling and unrolling to cover a wall.

[0041] The sheet material composition used in embodiments of the second aspect may be formed in the manner of a suspension, comprising powder suspended in a matrix material. The powder may be provided in the form of ground material. Specifically, the ground material may be made from natural or waste materials, such as grounds or dust created as by-product from stone cutting operations, charcoal, organic materials such as leaves, tea dust, egg shell, and other materials.

[0042] The powder may have a high degree of homogeneity so as to appear uniform under visual inspection. Alternatively, the powder may have a lower degree of homogeneity or be of heterogeneous nature so as to appear textured under visual inspection. The powder may be provided in the form of granules, flakes, chips, files, and / or particulate matter such as fine dust or silicate minerals such as mica. The powder may comprise a mixture of different materials and a range of different particle sizes and particle shapes. The powder may comprise or constitute a pigment. The method may comprise maintaining the powder at a temperature suitable for mixing with the carrier matrix. The method may comprise soaking the powder to facilitate mixing it with the carrier matrix. The method may comprise sifting the powder to achieve a desired particle size distribution. The sheet material composition is preferably liquid, or sufficiently pourable, to allow a suspension to be mixed to a desired degree of homogeneity, and to allow it to be introduced into the mould.

[0043] The backing layer may be applied onto the sheet material composition in the mould. It was found that the handling of the sheets may be facilitated by adding a backing layer. A suitable backing layer may provide a support for a non-woven sheet material composition. The backing layer may be of woven form, of pressed fibre form, or other suitable network structures. The backing layer may be a composite fibre material, such as a mesh, fleece or felt. The fibrebased composition may be a fibre-reinforced polymer, including carbon, glass, and other types of fibre compositions. However, this is not necessarily a requirement in all embodiments of the invention.

[0044] It is preferable for the backing layer to have material properties that complement or otherwise support the sheet. Considerations mentioned in relation to the backing layer of the first aspect apply equally to backing layers used in embodiments of the second aspect.

[0045] The backing layer may be fibrous, porous or of similar composition that allows air exchange, or “breathing” through the backing layer. In this manner, the backing layer may be applied before the drying process is concluded, to allow it to be embedded into the sheet material composition.

[0046] In some embodiments, the method of the second aspect comprises using an aqueous dispersion binder material as the carrier matrix.

[0047] In some embodiments, the method of the second aspect comprises using a polymeric material as the carrier matrix. The carrier matrix may be a non-woven material to provide a fluid or pourable composition suitable for moulding, curing and demoulding when mixed with the powder.

[0048] In some embodiments, the method of the second aspect comprises using a material composition comprising latex, rubber, caoutchouc, or combinations thereof, as the carrier matrix.

[0049] The carrier matrix is preferable a binder material suitable for mould forming. Considerations mentioned in relation to the binder matrix of the first aspect apply equally to carrier matrix formulations used in embodiments of the second aspect.

[0050] In some applications, it may be preferable for the material of the first and / or second aspects to have a relatively high softening point so as to be useable as wall covering in warm rooms, including shop windows, near radiators, and similar environments. The carrier matrix material may comprise a hardening composition so as to provide a suitably high softening point. In some embodiments, the softening point is no lower than 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 250°C, 300°C, 350°C or no lower than 400°C.

[0051] In some applications, it may be preferable for the material of the first and / or second aspects to have a relatively low softening point, for instance in the region of 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or 55°C. A lower softening point may facilitate thermoforming the sheet temporarily, for instance during application as a surface covering on a corner. In that case, the material may be temporarily warmed, e.g. using a blow dryer, to reduce the likelihood of crack formation while bending a sheet around a corner. As will be appreciated, different sheet variants may be provided with different softening points, depending on the location and geometry of the surface to which the sheets are intended to be applied.

[0052] In some embodiments, the sheet material composition used in the second aspect is prepared according to any one of the embodiments of the first aspect.

[0053] In some embodiments, providing a mould comprises forming a profiled positive, and forming a profiled negative by applying a mould material to the profiled positive, letting the mould material set, and separating the profiled positive from the profiled negative to provide the profiled negative as the mould.

[0054] By “profiled” positive, a positive is meant that has a surface that is other than a flat profile comprised of a single level surface. The profile of the positive is understood to correspond to the profile to be reproduced in the sheet. In this manner, a mould shape can be formed as a negative complementarily to the desired profiled positive.

[0055] In some embodiments, forming a mould comprises using 3D printing to create a mould.

[0056] The mould may be formed by additive manufacturing methods, specifically additive deposition methods comprising a curable material deposited in printable form and allowed to set to form a mould device.

[0057] A mould of this form may be created directly from a software instruction without reliance on a physical positive shape, although such a positive shape could be used, e.g. scanned, in the creation of a computer design model that is used for the creation of 3D printing instructions.

[0058] The mould is preferably made from a material composition suitable for temporary deformation to facilitate demoulding. An exemplary material for a mould is silicone material, although other suitable materials may be used. Silicone materials, for instance, are available as 3D printing medium, which would allow a 3D printed silicone mould to be manufactured.

[0059] In some embodiments, the mould comprises a base of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of at least 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or at least 0.6 mm.

[0060] In some embodiments, the mould comprises a base of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of no more than 1 mm, 1 .5 mm, 2 mm, 2.5 mm, or 3 mm.

[0061] By “contour level”, a region or area is meant that has the same height, e.g. spacing from a base of the mould or spacing from a deeper or higher region of the sheet.

[0062] The surface of each contour level, and of the base, may be generally planar. In practice, the surface of one or more contour levels and / or of the base may comprise a texture, which may be tolerated or may be added deliberately.

[0063] It will be appreciated that contour levels are distinguished from texture, which may be randomly distributed. In contrast, contour levels are provided by a defined, practically consistent level-to- level distance defining two or more discrete levels. To provide an illustrative example using representative distance numbers, a first contour level may be a base level at 0 mm height, a second contour level may be at a level of 0.5 mm above base level, and a third contour level may be at a level of 0.9 mm above base level and / or 0.4 mm above the second contour level.

[0064] The inventor was able to achieve a good level of precision of contour levels by combining laser guiding or other similar tools, and by first creating a positive from a wood prototype from which the mould is cast. In this manner, moulds of several square meter size, e.g. 1 m x 3 m area, having profiles with sub-millimetre level-to-level distances, were achieved.

[0065] In some embodiments of the second aspect, a surface of the sheet is contoured and comprises two or more discrete contour levels, or height regions. During the development of this aspect, it was found that the difference between contour levels, or level-to-level distance, may not need to be much in order to achieve a strong visual pattern effect.

[0066] This is believed to be the case at least in part because the different contour heights result in different thickness of the sheet material composition, which affects the appearance, such as the intensity of the colour, of the sheet material composition. In this manner, a cover sheet material can be created with two or more hues of a colour by applying a single type of sheet material composition.

[0067] It will be appreciated that the planar extension of different contour levels may be generally plane-parallel to the base and / or other contour levels. However, this is not necessarily the case in all embodiments, and some embodiments may comprise an oblique planar orientation. This is believed to provide a gradient hue effect.

[0068] In some embodiments, the mould comprises at least two discrete contour levels. In this manner, a sheet appearing to comprise two different colour hues can be created.

[0069] In some embodiments, the mould comprises at least three discrete contour levels. In this manner, a sheet appearing to comprise three different colour hues can be created. The profile may comprise a pattern of different regions, or “islands”, that are laterally spaced apart and each have a corresponding contour level.

[0070] In some embodiments, the method comprises drying the sheet at least partially prior to demoulding. The drying may be carried out using suitable equipment, such as an oven. In a preferred embodiment, the sheet is allowed to dry in a free environment, e.g. to air-dry. The drying process may improve the embedding into, or attachment of the backing layer on the sheet.

[0071] In some embodiments, the method comprises continuing to dry the sheet after demoulding. After a sufficiently long drying time in a mould, the sheet may be sufficiently consolidated to allow it to be manipulated for transfer to a drying rack. In this manner, a mould can be freed for reuse.

[0072] In some embodiments of the first and second aspects, the method comprises placing the sheet on a rack structure suitable for air drying. The sheet, dried on a surface, or whether in a mould or demoulded, may be placed on a rack structure. The rack structure may comprise multiple regions or shelves, for instance for 10 or 20 sheets, or more, each spaced apart by a stack height permitting ventilation for air drying.

[0073] In some embodiments of the first and second aspects, the method comprises drying the sheet for at least 24 hours. It will be understood that the drying time depends on the choice of material composition of the matrix, composition of powder, thickness of the sheet, and other factors such as ventilation, temperature and humidity levels of the drying environment. In accordance with a third aspect of the invention, there is provided a sheet material manufactured according to method steps of any one of the embodiments of the first aspect or the second aspect.

[0074] In accordance with a fourth aspect of the invention, there is provided a surface covering manufactured according to method steps of any one of the embodiments of the first aspect or the second aspect.

[0075] In some embodiments of the third and fourth aspects, the sheet material or surface covering, respectively, comprises a top layer of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of at least 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or at least 0.6 mm.

[0076] In some embodiments of the third and fourth aspects, the sheet material or surface covering, respectively, comprises a top layer of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of no more than 1 mm, 1 .5 mm, 2 mm, 2.5 mm, or 3 mm.

[0077] In some embodiments of the third and fourth aspects, the sheet material or surface covering, respectively, comprises at least two discrete contour levels or at least three contour levels.

[0078] In some embodiments of the third and fourth aspects, the sheet material or surface covering, respectively, has a length of no less than 1 metre. The sheet may be made to a length of at least 1 metre, 2 metres, 3 metres, or more. In embodiments, the sheet is made to length sufficient for a single sheet to cover the vertical extension of a room, e.g. from ceiling to floor. Most residential dwellings are expected to have a room height of no more than three metres. Some residential and commercial settings may require longer sheets, e.g. of 4 or more metres, which is possible with a sufficiently dimensioned mould.

[0079] In some embodiments of the third and fourth aspects, the sheet material or surface covering, respectively, has a width of no less than 20 centimetres. The sheet may be made with a width of at least 20cm, 30cm, 50cm, or at least 1 metre. Due to the flexible property of the sheet, it may be transported in roll form. To this end, it is believed that a width in the region of between 1 to 2 metres provides a practical size determining the length of a roll of material for transport. However, other width and length dimensions may be used depending on application requirements. In some embodiments, the backing layer comprises a mesh or fibre based composition. The backing layer may be partially or fully embedded in the sheet material.

[0080] In some embodiments, a level-to-level distance between a highest planar contour level and a lowest planar contour level is no more than 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1.5 mm. A surprising effect noted during the development of the embodiment was that a sheet may be made relatively thin, in the region of 1-3 mm, with multiple contour levels. This achieves a few practical effects, namely that a sheet material can be made thinner, and is therefore easier to dry and more likely to be pliable or flexible for handling. However, this is not an inherent requirement of all embodiments. If desired, a thicker sheet may be formed.

[0081] In some embodiments, the edges between different contour levels are of stepped form. Stepped edges have been found to provide a visually prominent boundary between contour levels, which may also correspond to the hue or shade of a profile. The stepped edges may be considered a discontinuous transition between two contour levels. To facilitate demoulding, an edge of stepped form may comprise a taper or sidewalls oriented at an oblique angle, i.e. other than perpendicular relative to the base of the sheet. However, if flexible moulds or sheet material compositions are used, and due to the shallow step height, demoulding may be facilitated without reliance on tapered edges.

[0082] Features described in relation to any one or more of the embodiments of the first aspect and second aspect may be combined with, or used for the manufacture of, one or more embodiments of the third aspect and / or the fourth aspect.

[0083] Description of the Figures

[0084] Exemplary embodiments of the invention will now be described with reference to the Figures, in which:

[0085] Figure 1 shows a sequence of exemplary steps of a method aspect of the invention;

[0086] Figure 2 shows a prototype sheet;

[0087] Figure 3 shows prototype sheets;

[0088] Figure 4 shows a sequence of exemplary steps of another method aspect of the invention;

[0089] Figure 5 shows a prototype positive profile;

[0090] Figure 6 shows a prototype mould corresponding to the Figure 5 profile;

[0091] Figure 7 shows an intermediate sheet product;

[0092] Figure 8 shows a prototype profiled sheet according to an embodiment;

[0093] Figure 9 shows a mould for a wall covering sheet;

[0094] Figure 10 shows a wall covering sheet made to the Figure 9 mould; Figure 11 illustrates a racking for drying step;

[0095] Figure 12 illustrates the Figure 10 sheet in a bent configuration;

[0096] Figure 13 illustrates an alternative example of a profiled sheet;

[0097] Figure 14 illustrates an exemplary illustration using two profiled sheets; and

[0098] Figure 15 is a schematic illustration of a section through a portion of a profiled sheet.

[0099] Description

[0100] Referring first to Figure 1 , a method 10 of forming a sheet material comprises a step 11 of providing a powder material. The powder material may comprise and / or be constituted by natural waste material, e.g. coffee, including ground coffee and / or used coffee grounds. In step 12, the water content of the powder material is adjusted. An appreciation underlying the invention was that particularly waste material such as coffee grounds may have considerably heterogenous water or moisture content. Waste coffee grounds may be several days old by the time they become available for use in the method. The method may use coffee grounds of different age and water content (dryness). The coffee grounds may be allowed to dry. As will be appreciated, the coffee grounds may have to be spread out or suitably prepared, as this will reduce the risk of mould developing or the grounds otherwise deteriorating. Counterintuitively, it was found that the coffee material so prepared, or at least some portions of the coffee material that are part of a homogeneous mixture, may require their humidity level to be increased to achieve a relatively even distribution of moisture content. To provide an illustrative value, the powder material may be brought to a water content in the region of between 5% to 30% water (w / w), preferably no less than 3%, 4%, or 5%, and depending on embodiment no more than 10%, 15%, 20%, 25%, or no more than 30% water content.

[0101] In step 13, the powder material is admixed to a binder matrix, such as an organic binder material, or a water-based binder material. In step 14, the mixture is blended to adjust the degree of homogeneity to a desired level. Steps 13 and 14 may be carried out concurrently. The powder material may have to be admixed gradually while blending the mixture of powder material and binder material, to gradually increase the concentration of powder material while avoiding the formation of pockets of clumped, unsuspended powder material. In test batches, about 2 / 3 coffee powder were admixed to 1 / 3 of latex material as binder (i.e., 2 parts coffee grounds per 1 part binder matrix) to create a sheet material composition. In another test batch, about 2 / 3 coffee powder were admixed to 1 / 3 of aqueous binder material (i.e., 2 parts coffee grounds per 1 part binder matrix) to create a sheet material composition. The powder material may constitute at least 40%, 50%, 60% or at least 70% (w / w) of the blended sheet material composition. During or prior to step 14, an optional step 15 may be carried out in which water may be admixed to the sheet material composition to adjust its consistency. For instance, it may be desirable for the consistency to be sufficiently thick for the sheet material composition to be spreadable on an even surface, to be applied as a layer of desired thickness using a spreading tool such as a spatula or screeding tool.

[0102] In step 16, a carrier surface is provided. The carrier surface may be provided by a backing layer, such as a fibre layer comprising woven or pressed fibre material. In step 17, the sheet material composition is applied to the carrier surface. If the carrier surface is constituted by a backing layer, the backing layer may be integrated into the sheet material composition, for instance by partially embedding the backing layer into the sheet material.

[0103] In step 18, the sheet material composition is spread across a predefined area to create a sheet layer of desired thickness. The sheet layer may be of a relatively even thickness. However, this is not necessarily a requirement of all embodiments. For instance, using suitably profiled tools, the surface of the sheet layer may be provided with texture such as grooves. It will be understood that the consistency of the sheet material layer will have been adjusted in steps 14 and 15 so as to be suitable for the formation of texture patterns, if this is desired.

[0104] In step 19, the sheet material composition is allowed to set to form a sheet. To this end, the free area of the sheet layer may be allowed to remain exposed to facilitate evaporation of water content. The sheet layer may have an area of more than one square metre. In an optional step 20, further powder material may be applied to the free surface of the sheet layer. Further powder material may be added while the sheet is drying, e.g. by rubbing in powder material, to embed the powder material with the binder material. In this manner, the appearance and texture of the sheet may be modified if desired. In step 21 , the sheet is allowed to dry, e.g. for at least 24 hours. As will be appreciated, the drying time may be determined by the thickness of the sheet layer, the water content, ambient temperature and humidity and other parameters. If was found by the inventors that slower drying times result in a sheet material that is more pliable, and less likely to crack. As such, the drying time may be longer than 24 hours. For instance, the drying time may be 2 or 3 days.

[0105] The drying process may be carried out in different locations. Initially, the sheet may be allowed to dry on the carrier surface, or backing layer, to which the sheet material composition was applied in steps 16 and 17. Once the sheet material is consolidated sufficiently to permit handling, the sheet material may be transferred to a drying station, e.g. after removal from the carrier surface. For practical purposes, the drying station may be provided by a rack or racking for several sheets. In a step 22, the sheet is removed, e.g. for transport, and may optionally be cut to a desired size or shape, and / or folded and / or rolled up to be provided in roll form.

[0106] Figure 2 illustrates a prototype sheet 1a on a backing layer 3a. Figure 3 illustrates two prototype sheets 1 b and 1c, cut to a rectangular sheet having an area of about 1 x 2 metres. The sheets 1a, 1 b, 1c are about 3 mm thin and flexible, and as such suitable as a surface covering, e.g., as a wallpaper, and are rollable for transportation.

[0107] The invention allows organic matter waste material, or natural waste material, of considerable heterogeneity, such as coffee grounds from different sources and of different age, to be used to provide colour and texture to a wallpaper. The sheet material may be used as a surface covering walls, ceilings, partitions, or for products, in the manner of a veneer.

[0108] Using a suitable backing layer, for instance a backing layer material that is stitchable, or adhesive backing, the sheet material may be used as a covering in the manner of faux leather, for use as wallets, cases, sleeves, or covers for books, bottles, electronic items, etc., and also as fobs, badges, labels, satchels, straps, stationary, packaging, clothing items, patches, upholstery and / or furniture coverings, as well as signage, and the like. The surface of the sheet material may be provided with a printable surface so as to be suitable as printing substrate.

[0109] While it is contemplated that the sheet material composition of the invention is suited for spreading it onto a surface to create a sheet, it may be created in liquid form or as a pourable composition. In that case, the aforementioned blending steps 14 and 15 may be carried out until the sheet material composition is sufficiently pourable to allow it to be introduced into a mould. The mould will be understood to be of generally planar, flat bed form so as to allow a sheet to be formed from it. As will be appreciated, in that case, the carrier surface may be provided by a mould, and the method may comprise pouring the sheet material composition into the mould, allowing the sheet material composition to set to form a sheet, and demoulding the sheet. In that case, a backing layer may be applied onto the sheet material composition in the mould prior to, during, or after setting.

[0110] In thicker form, embodiments of the invention may be used as a covering material, for instance provided on a roll, in the manner of wallpaper. In thinner form, embodiments of the invention may be used as a cover sheer or veneer sheet to be applied to surface of a product, wherein the product may be a decorative wall cover or other product surface. The sheet material obtained in batch trials, and achievable in different embodiments of the invention, had a thickness of no more than 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm. As such, the thickness of the sheet material can be made relatively thin, although for practicality of handling and even application of the sheet material composition to a carrier surface, the thickness may be at least 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or at least 1 mm.

[0111] When provided with a backing layer, the backing layer may be a fibre material of a thickness in the region of 0.1 mm to 0.4 mm. In trials, fibre backing layers were used with a thickness in the region of 0.2 mm and 0.3 mm, e.g. a nominal thickness of 0.25 mm. For instance, depending on the presence and thickness of a backing layer, the sheets may be in the region of 1 mm to 3 mm thick, In the absence of solid particles on the surface.

[0112] Referring now to Figure 4, Figure 4 shows steps of a method 130 in accordance with a second aspect of the invention for the manufacture of a profiled sheet material or a surface covering. In step 132, a powder material is provided and prepared, e.g., brought to an appropriate temperature to be suitable for mixing with a carrier matrix. In step 134, the powder is mixed with a carrier matrix to provide a sheet material composition. The sheet material composition may be provided in the form described above in relation to steps 11 to 15, using for instance ground coffee powder and an aqueous binder matrix, although this is not necessarily a requirement of all embodiments of the second aspect.

[0113] In step 136, a mould is provided that comprises discrete contour layers. Step 136 may be carried separately to steps 132 and 134. In an optional step 138, the mould or portions thereof, for instance the base of the mould, is lined with some of the powder material and an optional thin layer of carrier matrix material. The optional step 138 may be carried out to ensure positioning of some of the solids of the powder near the surface of the surface covering, or to expose some of the solids on the surface. Step 138 may be omitted if the presence of solids on the surface of the covering is not desired.

[0114] In step 140, the sheet material composition is introduced into the mould. Depending on the composition of the material, it may be poured or spread on the mould. For instance, step 140 may be carried out in the manner of steps 17 and 18. The sheet material composition is, initially, relatively liquid and will be allowed to set by drying. In step 142, a backing layer is applied to the sheet material composition. The backing layer may be of fibrous or mesh form, such that some of the sheet material composition may seep into or through the backing layer. This may achieve an embedding effect. If the method comprises introducing sheet material composition into a mould, it will be appreciated that the sheet material composition may be runnier, less viscous, than when it is applied to be spread on a flat surface. However, if mixed to appropriate consistency, the carrier matrix may be provided by binder matrix described in relation to the method 10 in Figure 1.

[0115] In step 144, the sheet material composition is allowed to set by drying. The drying process in step 144 may carried out until the sheet is sufficiently solid for demoulding. The method may proceed to step 146 before the sheet is dried out completely. In step 146, the sheet is demoulded from the mould. The sheet has some flexibility that assists with the demoulding. Likewise, the mould may be of a flexible structure such that the sheet and / or mould may be temporarily deformed, e.g. by bending, for demoulding.

[0116] In an optional step 148, further powder material may be applied to the free surface of the sheet (i.e., the face opposite the side provided with a backing layer). Optional step 148 may be carried out instead of, or in addition to, an optional step 138. Step 148 may be carried out if additional powder material is desired to be visible on the surface. Step 148 may be carried out before the sheet has been dried fully, to assist with embedding, or “rubbing in” of powder into the sheet.

[0117] In step 150, the sheet is allowed to dry further after demoulding, if required. The drying process may be an air-drying process lasting several hours or days. The drying process may, alternatively, be carried out in an oven or other suitable drying equipment.

[0118] At the end of method 10, for instance as part of step 22 (see Figure 1), and / or in an optional step 152 at the end of method 130, additional finishing steps may be carried out. The surface of the sheet may be covered wholly or in part with one or more layers of a sealant or sealing layers. The surface of the sheet may be coloured with additional patterns if desired. Other surface finishes such as polishing or roughing may be applied.

[0119] Furthermore, the sheet may be cut to a desired shape or size, and / or may be provided with holes to accommodate fixtures such as sockets, access covers, handles and the like. Due to the relatively thin dimension of the sheet, it is relatively easily cut with a good degree of precision.

[0120] Different finishing procedures may be carried out as part of step 22 or step 152, respectively. Not all the finishing procedures of step 22 or step 152 are necessarily carried out as part of the sheet manufacturing process. Some of the finishing procedures may be carried out at the time of applying the surface covering to a surface.

[0121] Referring now to Figures 5 to 15, these show illustrations of components used in the manufacture of a surface covering sheet, and example embodiments. Figure 5 illustrates a profiled positive 30 comprising a body 32. The body 32 comprises a generally flat base with (here:) four lower regions 34a, 34b, 34c, 34d that are recessed deeper than (here:) four higher regions 36a, 36b, 36c, 36d. The level of the four lower regions 34a-d is generally the same and constitutes a first discrete contour level. The level of the four higher regions 36a-d is also the same and constitutes a second discrete contour level. The level-to-level distance between the first and second discrete contour levels is in the region of 1 millimetre. Figure 6 shows a mould 40 made from silicone as imprint of the profiled positive 30. The mould 40 comprises a mould body 42 with generally flat profile comprising contoured regions that are discretely spaced apart (in a level-to-level direction), corresponding to the contour levels of the body 32. As such, the mould body 42 comprises a plurality of (here:) four lower regions 46a, 46b, 46c, 46d that are recessed deeper than (here:) four higher regions 44a, 44b, 44c, 44d.

[0122] Figure 7 shows the mould 40 and applied to it an amount of sheet material composition 50a. The sheet material composition 50a is applied in pourable form and allowed to set. Prior to setting, the sheet material composition 50a is covered with a fibre sheet 58 to embed it with the composition 50a.

[0123] Figure 8 shows a demoulded sheet 50 made from the demoulded sheet material composition 50a. The sheet 50 is contoured corresponding to the contoured profile levels of the mould 50 (Figure 3) and the profiled positive 30 (Figure 2). As such, the sheet 50 comprises a generally flat base with (here:) four lower regions 54a, 54b, 54c, 54d that are recessed deeper than (here:) four higher regions 56a, 56b, 56c, 56d.

[0124] Figures 5 to 8 show steps and components used for the manufacture of a prototype sheet having a size of about 30cm x 30cm.

[0125] Figure 9 shows a larger mould 60 comprising a mould body 62 provided with a profiled pattern having (here) two different contour levels. The mould has a size of about 1 m width x 3m length, to allow a sheet of corresponding dimensions to be made.

[0126] Figure 10 shows a second sheet 70 constituting a surface covering, after demoulding. The second sheet 70 has a size corresponding to mould 60, of about 1 m width x 3m length. This allows the second sheet 70 to be used as a unitary component to cover a length (e.g., a height of a wall) of up to 3 metres. The second sheet 70 is provided with a profiled pattern corresponding to the profiled pattern of the mould body 62, with recessed regions 74 and higher regions 76.

[0127] The second sheet 70, as illustrated in Figure 10, may be in a condition just after demoulding. Depending on the composition of the carrier matrix and the sheet material, and depending on the sheet thickness and environmental factors such as temperature and humidity, a sheet of this size may require several hours or days to dry fully.

[0128] Figure 11 shows a drying rack arrangement 80 comprising a plurality of shelves 82, here provided in the form of pallets stacked on top of each other, that allows a relatively large number of large surface coverings to be dried simultaneously. The second sheet 70 has a thickness of only a few millimetres, in the region of 2-3 millimetres, and is sufficiently flexible to allow it to be rolled or folded. Figure 12 shows the sheet 70 hanging over a support frame, its body in a bent or folded configuration 72a.

[0129] Figure 13 shows a third sheet 90 comprising a sheet body 92 comprising a profiled pattern with recessed regions 94 and higher regions 96. The third sheet 90 has a size of about 1 m width x 3m length. The lower and higher regions have the same contour level. Comparing Figures 10 and 13, the method allows different sheet designs for relatively large area sheets to be manufactured repeatedly.

[0130] Figure 14 shows a test installation 78 using two sheets 70a, 70b as a wallpaper. It will be appreciated that the sheets 70a, 70b extend over the full height of the walls underneath, in a unitary manner, without joint lines. The flexible character of the sheets allows the sheets to be applied by unrolling them on the wall, e.g. from top to bottom or from ceiling to floor.

[0131] Figure 15 illustrates a schematic side view of a sheet structure 100 to visualise an embodiment with more than two contour levels (here: three contour levels). The sheet structure may be manufactured by the method 10 described above. The sheet structure 100 comprises a backing layer 120 embedded with a base layer 112 at a first interface 102. The base layer 112 comprises a first contour level 104 of generally planar extension. The first contour level 104 may be provided with a texture, or may be smooth. Protruding above the first contour level 104 is a first contour layer 114 having a generally even thickness (contour height) corresponding to a second contour level 106. Above the second contour level, a further, second contour layer 116 protrudes having a generally even thickness (contour height) corresponding to a third contour level 108. The edges of the second contour layer 116 are constituted by a step 124 providing a defined boundary between the second contour layer 116 and the first contour layer 114. Likewise, the edges of the first contour layer 114 are constituted by a step 122 providing a defined boundary between the fist contour layer 114 and the base layer 112. Although illustrated as layers for the purpose of emphasising the contoured levels, the base layer 112 and the first and second contour layers 114, 116 of the sheet structure 100 are unitary and made up of the same sheet material composition. The thickness (height) of the layers may be in the region of a millimetre or less. For instance, the height of the sheet structure 100 may be no more than 2 or 3 millimetres, e.g. in the region of 1 to 3 mm.

[0132] The sheet material composition used for the manufacture of the sheets 50 (Figure 8), 70 (Figures 10, 12, 14) and 90 (Figure 13) is relatively homogenous, yet provides a visually discernible pattern aligned with the different thicknesses of the contour levels. The different hues or shades may be made more prominent by appropriate selection of the backing layer, for instance by selecting a bright (e.g., white) backing layer or a darker (e.g., black) backing layer. It will be appreciated that the description hereinbefore is exemplary in accordance with embodiments of different aspects of the invention, and that a wide range of modifications and alterations may be made thereto without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. A method of forming a sheet material suitable as a surface covering, the method comprising: providing a powder material; adjusting water content of the powder material; admixing the powder material to a binder matrix; blending the powder material and the binder matrix to create a sheet material composition; providing a carrier surface; applying the sheet material composition to the carrier surface; spreading the sheet material across at least a portion of the carrier surface to provide a sheet layer; and allowing the sheet material composition to set to form a sheet.

2. The method according to claim 1 , wherein the powder material comprises ground coffee.

3. The method according to claim 2, wherein the powder material comprises a blend of different types of ground coffee.

4. The method according to any one of the preceding claims, wherein the powder material comprises coffee grounds.

5. The method according to any one of the preceding claims, wherein the binder matrix comprises an aqueous dispersion binder material.

6. The method according to any one of the preceding claims, wherein the binder matrix is provided by a polymeric material.

7. The method according to any one of the preceding claims, wherein the binder matrix is provided by a material composition comprising one or more constituents from a group including latex, rubber, caoutchouc, or combinations thereof.

8. The method according to any one of the preceding claims, wherein providing the powder material comprises grinding a precursor material.

9. The method according to any one of the preceding claims, wherein providing the powder material comprises sifting a precursor material.

10. The method according to any one of the preceding claims, wherein adjusting the water content of the powder material comprises drying the powder material.11 . The method according to any one of the preceding claims, wherein adjusting the water content of the powder material comprises adding water to the powder material.

12. The method according to any one of the preceding claims, comprising adjusting the water content of the powder material to between 5% and 30% w / w.

13. The method according to any one of the preceding claims, wherein blending the powder material and the binder matrix comprises homogenising the sheet material composition.

14. The method according to any one of the preceding claims, wherein the carrier surface is provided by a backing layer.

15. The method according to any one of the preceding claims, comprising spreading the sheet material evenly across at least a portion of the carrier surface to provide a sheet layer of even thickness.

16. The method according to any one of the preceding claims, comprising leaving a free surface of the sheet layer exposed.

17. A method of forming a surface covering suitable for attachment to a surface, the method comprising: preparing a sheet material composition of liquid or pourable form using a powder and a carrier matrix; mixing the powder with the carrier matrix to form the sheet material composition; providing a mould shaped to form a sheet material; introducing the sheet material composition into the mould; applying a backing layer to the sheet material composition in the mould; allowing the sheet material composition to set to form a sheet; and demoulding the sheet to provide the surface covering.

18. The method according to claim 17, comprising using an aqueous dispersion binder material as the carrier matrix.

19. The method according to claim 17, comprising using a polymeric material as the carrier matrix.

20. The method according to claim 17, comprising using a material composition comprising latex, rubber, caoutchouc, or combinations thereof, as the carrier matrix.

21. The method according to claim 17, wherein the sheet material composition is prepared according to any one of claims 1 to 13.

22. The method according to any one of claims 17 to 21 , wherein providing a mould comprises forming a profiled positive, and forming a profiled negative by applying a mould material to the profiled positive, letting the mould material set, and separating the profiled positive from the profiled negative to provide the profiled negative as the mould.

23. The method according to any one of claims 17 to 22, wherein forming a mould comprises using 3D printing to create a mould.

24. The method according to any one of claims 17 to 23, wherein the mould comprises a base of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of at least 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or at least 0.6 mm.

25. The method according to any one of claims 17 to 24, wherein the mould comprises a base of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of no more than 1 mm, 1 .5 mm, 2 mm, 2.5 mm, or 3 mm.

26. The method according to claim 24 or 25, wherein the mould comprises at least two discrete contour levels, or wherein the mould comprises at least three discrete contour levels.

27. The method according to any one of claims 17 to 26, comprising drying the sheet at least partially prior to demoulding.

28. The method according to any one of claims 17 to 27, comprising continuing to dry the sheet after demoulding.

29. The method according to any one of the preceding claims, comprising placing the sheet on a rack structure suitable for air drying.

30. The method according to any one of the preceding claims, comprising drying the sheet for at least 24 hours.31 . A sheet material produced according to the method of any one of the preceding claims.

32. A surface covering produced according to the method of any one of claims 1 to 30.

33. The sheet material according to claim 31 or the surface covering according to claim 32, comprising a top layer of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to- level distance of at least 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or at least 0.6 mm.

34. The sheet material according to claim 31 or 33, or the surface covering according to claim 32 or 33, comprising a top layer of generally planar extension comprising a plurality of discrete contour levels, wherein two adjacent discrete contour levels are set apart from each other by a level-to-level distance of no more than 1 mm, 1 .5 mm, 2 mm, 2.5 mm, or 3 mm.

35. The sheet material or surface covering according to any one of claims 31 to 34, comprising at least two discrete contour levels or at least three contour levels.

36. The sheet material or surface covering according to any one of claims 31 to 35, having a length of no less than 1 metre.

37. The sheet material or surface covering according to any one of claims 31 to 36, having a width of no less than 20 centimetres.

38. The sheet material or surface covering according to any one of claims 31 to 37, wherein the backing layer comprises a mesh or fibre-based composition.

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