Improved decking / cladding plank

Abstract

A method of producing a plank, comprising the steps of providing a mould of a plank with an inner relief corresponding to the configuration of the relief which is to be formed on at least part of the outer surface of a plank; partially filling the mould with an elastomer; melding the elastomer with a further composition comprising a filler dispersed within a polymeric matrix; wherein the polymeric matrix is formed from monomers, wherein at least one of the monomers is a polyol; said composition further comprising a blowing agent; projecting fibre sections into the further composition as it is sprayed or poured into the mould; whereby fibre sections are randomly oriented and multidirectionally retained within a resulting foam of polymer and filler.

Description

Field of the Invention The invention relates to planks. In this specification the term “plank" covers both a “decking plank” and a “cladding plank”. A “decking plank” is a plank capable of being suspended on two or more support points without significantly bending out of the natural plane of the plank when carrying a weight such as a person. It does not necessarily require to be laid flat on a floor in order to substantially retain its shape. A “cladding plank” is a plank that is used to cover or coat (e.g. for decorative effect) a material or structure (e.g. a house) without bending out of the natural plane of the plank. In other words, planks within the meaning of the present invention are self-supporting. Background to the Invention and prior art known to the applicant(s) Many “planks” known in the art are not suitable for use as a decking plank or a cladding plank because they are designed to necessarily be laid flat against the floor to be fully supported along their length. As such, these prior art “planks” are not self-supporting. However, to provide a self-supporting structure, a compromise needs to be struck between the rigidity of the components and the brittleness of the material. For example, decking planks must be capable of withstanding forces associated with users walking, sitting and / or standing. As such, the decking planks must be flexible enough such that they do not break in use, but strong enough that they are self-supported and do not bend out of the natural plane of the plank. It is also important that the materials used do not result in a plank that is too heavy to be suspended. The closest prior art to the invention is one of the present inventor’s own prior publication dated 2007 under reference WO2007060392A1. Initially, amongst the potentially available readymade support beams, extruded polymer based support beams were envisaged as the primary embodiment for the production of decking planks with sufficient bulk, and bending resistance. Extruded beams were readily available and could thus be covered with a layer of cushioning material and an upper layer with appropriate relief to adopt the appearance of natural wood whilst being at the same time wholly of plastics material. The development of the art was thus to focus initially on producing support beams and then adding to these subsequent covering layers in separate manufacturing steps. Brittleness and general weakness of the boards were witnessed in many prior ait embodiments. Fibre matting was thus provided as a layer affixed to the core to seek to reinforce the planks. Thus, prior art embodiments were formed in segregated layers of 1) an extruded polymeric beam, 2) a fibre matting on one side of the extruded polymeric beam, 3) a polyurethane layer with filler, and 4) a covering layer. This structure was found to be prone to delamination. The present invention sets out a number of improvements in the method of manufacture of planks and resulting in improved planks. In particular, certain embodiments of the invention seek one or more of the following: • To provide a method of producing a plank with greater integrity to minimise any risk of delamination; • To provide a method which reduces the relative amount of plastics material used in the core whilst providing advantageous bulk and strength to function as a self-supported plank; • To provide a plank which is more durable and requires no maintenance; • To have enhanced natural appearance whilst providing a soft feel and advantageous anti-split properties. Summary of the Invention hi a first broad independent aspect, the invention provides a method of producing a plank (e.g. decking, e.g. cladding), comprising the steps of: • providing a mould of a plank with an inner relief corresponding to the configuration of the relief which is to be formed on at least part of the outer surface of a plank; • partially filling the mould with an elastomer; • melding the elastomer with a further composition comprising a filler dispersed within a polymeric matrix; wherein the polymeric matrix is formed from monomers, wherein at least one of the monomers is a polyol; said composition further comprising a blowing agent; and • providing randomly oriented fibre sections to said further composition; whereby said fibre sections are multidi rect ion ally retained within a resulting foam of polymer and filler. In certain embodiments, this configuration is particularly advantageous as the core entirely avoids the prior art requirement of placing a separately manufactured extruded support beam into a mould. Whilst providing a much more efficient manufacturing process, the method may, in certain embodiments, lead to the manufacturing of a plank which has improved strength and durability whilst occupying an expansive volume in which the amount of plastics has been minimised relative to the relatively large volume occupied and the relatively large thicknesses associated with the plank of the kind in question. This improves the environmental credentials of the board because there is a lower density of plastics material whilst preserving the prior art advantages of extensive durability when compared to natural wood which tends to rot (potentially very fast in damp environments) and be particularly susceptible to cracking due to fluctuations in temperature. Furthermore, in certain embodiments, the elastomer and the further composition form an improved bond without the use of adhesives and the elastomer only partially fills the mould and then the further composition is poured over the elastomer as the fibre sections are propelled into the mixture. Furthermore, it provides improved comfort under foot, avoiding the risk of splinters and little or no risk of delamination of the adjacent layers as they are melded together preferably in a single operation. In a subsidiary aspect, the invention provides the step of projecting fibre sections into the further composition as it is sprayed or poured into the mould. This configuration is particularly advantageous as it leads to a multidirectional orientation of fibre sections which improve the mechanical strength of the board without causing the plank to warp as prior art fibre mats would. In a further subsidiary aspect, the fibre sections are mixed into an air jet for projecting into the further composition. This configuration is particularly efficient in terms of causing the advantageous random orientation of fibre sections in the core of the plank which provide additional strength and resistance to bending whilst minimising or entirely avoiding undesirable fractures. Furthermore, it provides a clean and efficient transportation of the fibre sections into the mixture. In a further subsidiary aspect, the weight ratio between the polyol and the filler is less than 1:2.6. In other words, the weight of the filler is up to 2.6 times the weight of the polyol. In a further subsidiary aspect, the weight ratio between the polyol and the filler is from 1:1.8 to 1:2.6. In other words, the weight of the filler is from 1.8 to 2.6 times the weight of the polyol. These ranges are particularly advantageous as they further reduce the amount of plastics material required to produce the bulk of the reinforced core. Thus, the core content of plastics is minimised in favour of closed cells containing gas, fibre sections and particulate fillers. This is achieved by providing high levels of toughness and strength. The board thus providing environmental advantages from the point of view of replacing the need to employ wooden planks whilst at the same time minimizing the use of plastics. In a further subsidiary aspect, the weight ratio between the polyol and the filler is greater than 1:1. In other words, the weight of the filler is lower than the weight of the polyol. In a further subsidiary aspect, the filler is a mineral filler. This configuration is particularly advantageous as it further reduces the contents of plastics in the core whilst providing advantageous mechanical properties. In a further subsidiary aspect, the method comprises the further step of selecting up to substantially 100% of the filler from recycled materials. In a further subsidiary aspect, the method further comprises the step of forming the polymeric matrix by mixing polyol monomers with isocyanate monomers which act as a blowing agent. In a further subsidiary aspect, the method further comprises the step of mixing the elastomer and a filler prior to pouring and / or spraying the mixture of elastomer and filler into the mould. In a further subsidiary aspect, the method further comprises the step of placing ducts into the mould. This configuration is particularly advantageous as it allows ducts to be added into the mould to facilitate the circulation of fluids which would not be possible in the prior art extruded support beam. It also further improves the strength of the attachment of the ducts to the core without the use of adhesives. In a further subsidiary aspect, the mould is enclosed with a metallic lid with air vents to allow air to escape; the method further providing the steps of applying pressure to the filled mould during the setting process prior to demoulding. This configuration is particularly advantageous as it allows the removal of undesirable bubbles. In a further subsidiary aspect, the method further comprises the step of removing the plank from the mould by suction. This configuration is particularly advantageous as it allows particularly efficient demoulding whilst minimising any risk of damage in the process. In a further broad independent aspect, the invention provides a plank (e.g. decking, e.g. cladding) comprising: a core acting as a support beam; one or more cushioning layers comprising an elastomer which is retained onto the core; and an upper surface including an exposed relief, wherein the upper surface forms a slip-resistant surface; wherein the core comprises a composition comprising a filler dispersed within a polymeric foam matrix; wherein the polymeric foam matrix is formed from monomers, wherein at least one of the monomers is a polyol; and the core comprises randomly oriented fibre sections which are additional to the filler. This configuration reverses conventional thinking of employing woven mats of fibre and instead provides a core with greater strength in order to withstand bending whilst being produced, in at least certain embodiments, without extruded support beams. This configuration is also particularly advantageous because it allows splinter free decking to be produced which may also be made to resemble real wood or natural stone, by virtue of the relief surface, while simultaneously being both slip resistant and cushioned in order to be particularly comfortable and risk free to stand on. Certain embodiments of the present invention also have fewer tendencies of fungi growing on the deck particularly when the layers are of polymeric or plastics material. The slip resistance of the plank will be particularly advantageous when the surface is wet. Preferably, the upper layer is homogeneous which avoids the surface being abrasive or uncomfortable at least underneath the foot of the user. It also allows the relief of the upper surface to have natural-looking and soft-feeling depressions and projections. In a further subsidiary aspect, the weight ratio between the polyol and the filler is less than 1:2.6. In a further subsidiary aspect, the weight ratio between the polyol and the filler is from 1:1.8 to 1:2.6. In a further subsidiary aspect, the weight ratio between the polyol and the filler is greater than 1:1. In a further subsidiary aspect, the filler is a mineral filler. In a further subsidiary aspect, up to substantially 100% of the filler is formed from recycled materials. In a further subsidiary aspect, the polymeric matrix is formed from polyol monomers mixed with isocyanate monomers which act as a blowing agent. In a further subsidiary aspect, the polymeric matrix is a polyurethane material. In a further subsidiary aspect, the break strength of the core is greater than 4.6 MPa. In a further subsidiary aspect, at least one of the one or more cushioning layers comprises an elastomer and a filler. In a further subsidiary aspect, the core and the one or more cushioning layers are melded together without the use of adhesives. In a further subsidiary aspect, the plank further comprises a duct located at least partially inside the core. In certain embodiments, this may be particularly advantageous to secure the duct in one overall efficient process. hi a further broad independent aspect of the invention, a (e.g. decking, e.g. cladding) plank is provided. The plank comprises: a core acting as a support beam; one or more cushioning layers retained onto the core; and an upper layer including an exposed relief, wherein the upper layer forms a slip-resistant layer which at least partially covers the one or more cushioning layers. The core is made from a polymeric material comprising a filler material dispersed within a polymeric matrix. The polymeric matrix is formed from monomers, wherein at least one of the monomers is a polyol, wherein the weight ratio between the polyol and the filler is less than 1:2.6. Optionally, the weight ratio between the polyol and the filler is greater than 1:1. The polymeric matrix of any one of the aspect of embodiments of the invention will be described herein as a “polyol-based” polymeric matrix. A polyol based polymeric matrix, within the meaning of embodiments of the invention, is thus a polymeric matrix, wherein at least one of the monomers is a polyol. Optionally the plank is a decking plank. Optionally the plank is a cladding plank. Optionally, the cladding plank comprises an edge portion, preferably the edge portion is located on the external and / or outwardly facing surface (e.g. the surface which will be seen when the cladding plank is installed). Preferably, the edge portion provides a decorative feature. In preferred embodiments, the structural support is provided by the core which is relatively hard in comparison to the outer layers (e.g. the cushioning layers and the upper layer). Within the meaning of certain embodiments of the invention, a polyol is a molecule having at least two hydroxyl groups. For example, the polyol may have two hydroxyl groups (e.g. a diol), three hydroxyl groups (e.g. a triol), four hydroxyl groups (e.g. a tetrol), etc. Optionally, the polyols may be aliphatic or aromatic polyols. Optionally, the polyols are aromatic polyols. Optionally, the (e.g. aromatic) polyol is a low molecular weight (e.g. less than 2000) polyol. Optionally, the polymeric matrix is formed from polyol monomers mixed with isocyanate monomers. Optionally, the isocyanate monomers may be a diisocyanate monomer. Optionally the isocyanate monomer is added in excess (e.g. the polymerisation process is limited by the amount of polyol). Optionally, the polymeric matrix is a polyurethane. Optionally, the polymeric matrix is a foam. Optionally the polymeric matrix is a polyurethane foam. Optionally, the polymeric matrix in accordance with any of the aspects, further comprises fibre glass fibres for reinforcement. Within the meaning of embodiments of the invention, a filler material is a particulate material that can be dispersed within a polymeric base material to alter its physical properties. Generally, the addition of filler materials typically increases the (e.g. tensile, e.g. elastic) modulus of polymers and polymeric materials. As such, although a filler may allow a decrease in the amount of polymeric employed as it increases the bulk in combination with the polymeric material, it can also make polymeric materials more brittle and thus reduces the force at which the material will break which tend to make them unsuitable for use in plank structures, especially the components which are used to achieve the self-supporting structure (e.g. the core). However, the inventors have surprisingly found that, contrary to conventional thinking, the addition of a filler material within a specific range surprisingly does not reduce (and in some instances, even improves) the break strength and deflection at break. As such, the inventors have surprisingly found that a polymeric material including a filler within this identified range has an optimised compromise between the physical properties (e.g. stiffness necessary to ensure the plank is self-supporting) and the bulk achieved by the filler within the material. As noted above, the core acts as (e.g. is) a support beam for the decking plank without requiring a separate extruded support beam. As such, the core itself acts to ensure the plank is self-supporting. It will be appreciated that the upper layer may be formed by one of the one or more cushioning layers. Thus, in some embodiments the plank has one cushioning layer retained onto the core, wherein the cushioning layer includes an exposed relief and provides the slip-resistance layer. The cushioning layer thus acts as both the cushioning layer and the upper layer. In some embodiments, the plank has one (or more) cushioning layer(s) and a distinct upper layer, wherein the cushioning layer and the upper layer have (e.g. slightly) different compositions from each other. In some embodiments, the weight ratio between the polyol and the filler is from 1:1.8 to 1:2.6, e.g. from 1:2 to 1:2.5. For example, for every 1000 g of polyol used to make the polymeric material, at least 1800 g of filler material is added (i.e. a ratio of 1:1.8). For example, for every 1000 g of polyol used to make the polymeric material, no more than 2600 g of filler material is added. This allows the polymeric material for the core to be produced with less plastics material whilst still providing a strong core that can act as the main support for the plank whilst also allowing it to undergo the necessary bending moments when supported between two joists. As noted above, the core is made from a polyol-based polymeric matrix with a filler material dispersed therein. Optionally, the polymeric material may also include other materials dispersed within the polyol-based polymeric matrix, such as reinforcing fibres. However, the inventors of embodiments of the invention have surprisingly found that physical properties (e.g. break strength, e.g. deflection at break) of the core are significantly improved when a “base” polymeric material is used (e.g. into which other materials may be included or dispersed). In certain embodiments, the base polymeric material may be considered to be formed by the polyol-based polymeric matrix with the filler material dispersed therein, wherein the weight ratio between the polyol and the filler is less than 1:2.6, e.g. between 1:1 and 1:2.6, e.g. between 1:1.8 and 1:2.6. Optionally, the break strength of the “base” polymeric material is less than 150000 N / m2., e.g. less than 100000 N / m2, e.g. less than 90000 N / m2, e.g. less than 80000 N / m2, e.g. less than 70000 N / m2, e.g. less than 60000 N / m2. Optionally, the break strength of the core is from 30000 N / m2 to 150000 N / m2, e.g. from 40000 N / m2 to 100000 N / m2, e.g. between 50000 N / m2 to 80000 N / m2, e.g. from 60000 N / m2 to 70000 N / m2, e.g. approximately 64000 N / m2. It will be appreciated that the break strength is a measure of the force that is required to break an object. Thus, this allows the plank to be able to withstand the expected forces associated with use of the plank without breaking. Optionally, the break strength of the resulting core (i.e. formed from the “base” polymeric material and including other components or materials, such as reinforcing fibres) is greater than 3 MPa, e.g. greater than 3.5 MPa, e.g. greater than 4 MPa, e.g. greater than 4.6 MPa. Optionally, the break strength of the resulting core is from 3 MPa to 7 MPa, e.g. from 4 MPa to 6 MPa, e.g. from 4.6 MPa to 5.9 MPa. Optionally, the filler material is selected to be a mineral (e.g. limestone or calcium carbonate) filler material. Optionally, the filler material is high-purity (e.g. greater than 90%, e.g. greater than 95%, e.g. greater than 98%, e.g. greater than 99%, e.g. greater than 99.5%) carboniferous limestone powder. Optionally, at least 90% (e.g. at least 95%, e.g. at least 98%, e.g. at least 99%, e.g. substantially 100%) of the (e.g. limestone) filler material is formed from recycled materials. For example, the Superlon™ LI50 limestone filler may be used which is formed from 100% recycled materials. This allows embodiments of the invention to be particularly environmentally friendly and preserve and reuse resources responsibly. Optionally, the polymeric material further comprises reinforcing fibres. This allows the core to be strengthened to act as the main support for the plank and to allow it to undergo the necessary bending moments when supported between two joists. Optionally, at least one of the one or more cushioning layers comprises an elastomer and a filler (e.g. a “filled elastomer”). The filler of the cushioning layers and the filler material dispersed in the polymeric material of the core may be the same or different. Optionally, each of (e.g. all of) the one or more cushioning layers comprises an elastomer and a filler, hi some embodiments, all of the (one or more) cushioning layers may have the same composition, e.g. all of the (one or more) cushioning layers may be made from the same elastomer with the filler material at the same concentration (or loading). In some embodiments, some of the cushioning layers may have different compositions to each other. For example, some of the layers may be made from a different elastomer and / or may have a different filler and / or may have a different concentration of filler. This allows the cushioning layers to be relatively soft and / or elastic and provide a soft underfoot experience for the user when walking on the decking planks. Optionally, the upper layer comprises an elastomer. Optionally, the upper layer may comprise an elastomer and a filler (e.g. a “filled elastomer”). The filler of the upper layer and the filler material dispersed in the polymeric material of the core may be the same or different. In some embodiments, the upper layer comprises less filler than each of the one or more cushioning layers. For example, the weight % of filler in the upper layer is less than the weight % of filler in one of the cushioning layers. For example the upper layer contains no filler and the cushioning layer contains filler. This allows the upper layer to be softer than the cushioning layers, which in turn provides a better non-slip surface (especially when wet) and an improved underfoot feeling when a user walks on the decking plank. Optionally, the plank comprises a plurality of cushioning layers and an upper layer covering at least part of the cushioning layers; wherein one cushioning layer is a "filled elastomer" and the upper layer has a greater wear resistance with less filler than said cushioning layer, or, indeed, no filler at all. This configuration is particularly advantageous because it maximises the wear resistance of the plank, improves its cushioning effect whilst simultaneously reducing the costs of the material for production purposes. Optionally, the cushioning layer(s) of the plank has a Shore factor (A) within the range of around 20 to around 90 Shore (A). Optionally, the upper layer of the plank has a Shore factor (A) within the range of around 15 to around 85 Shore (A). Optionally, one or more of the cushioning layers comprise a resilient foam material. For example, the elastomer of the cushioning layers is polyurethane based, e.g. a polyurethane. Optionally, the elastomer of the upper layer is polyurethane based, e.g a polyurethane. This optional feature assists in achieving a cushioned feel to the plank as well as retaining the advantages discussed above in connection with the previous aspects. The filler used in the cushioning layers and / or the upper layers may also for example include calcium carbonate or fire-retardant fillers. Optionally, the plank has at least a top surface and a side surface, both of which are covered by at least one of the one or more cushioning layers. For example, the core has at least a top surface and a side surface, both of which are covered by at least one of the one or more cushioning layers. This configuration is particularly advantageous because it protects not only the top surface but the side surface and therefore further minimises any risk of slippage on the edges or of splinters when handling the plank. Optionally, the core is encapsulated by at least one of the one or more cushioning layers and / or the upper layer. This provides the advantage of further increasing the versatility of the plank, its ease of handling and its properties irrespective of which side a deck installer chooses to install the plank. This would also be particularly advantageous in terms of comfort for a user and would further reduce any risk of user accidents. Optionally, the upper layer covers at least the top surface of the decking plank. As such, the cushioning layers may be exposed on the sides of the decking plank. Optionally, the upper layer covers the top and the sides of the decking plank. As such, the cushioning layers at the top and the sides of the plank are covered by the upper layer. Optionally, the cushioning layers and core are encapsulated by the decking plank. Optionally, the plank further comprises multiple lateral projections on at least one side of the plank and recesses on at least one opposite side of the plank for mating engagement with the lateral projections of another plank. This optional configuration is particularly advantageous because it not only allows neighbouring planks to be secured to one another but it also allows them to be secured in predetermined relative positions so that no horizontal adjustment is required. Optionally, at least one of the plank's sides incorporates a groove. This allows a plurality of planks to be assembled to form a plank assembly surface (e.g. a deck). This would be particularly advantageous because it would accommodate hidden fixing. Optionally, the core and the one or more cushioning layers are melded together without the use of adhesives. This means that releasable attachment means are not used. This configuration is particularly advantageous because it allows the layers to act as their own adhesives without the use of separate adhesives as the layers set together during the manufacturing process. Optionally, the upper layer forms a top surface of the plank, wherein the top surface incorporates recessed portions indicating suitable locations for the insertion of one or more screws or the like. This avoids a user inadvertently severing the heating means during installation of the deck. It also avoids any requirement of having to use warning stickers indicating where it would not be suitable to insert screws. Alternatively, a template may be provided. Brief description of the figures Figure 1 shows a cross-sectional view of a plank in its mould when formed entirely by a moulding process. Figure 2 shows a block diagram of a preferred embodiment of the method in question. Figure 3 shows separate embodiments of a decking plank in cross-section. Figure 4 shows a cross-sectional view of a decking plank in accordance with a further embodiment of the invention. Figure 5 shows a cross-sectional view of a decking plank in accordance with a further embodiment of the invention. Figure 6 shows a cross-sectional view of a decking plank in accordance with a further embodiment of the invention. Figure 7 shows a cross-sectional view of a decking plank in accordance with a further embodiment. Figure 8 shows perspective view and a plan view of a plank in accordance with a further embodiment. Figure 9 shows a perspective view of two decking planks suitable for being joined together by a T-junction member. Figure 10 shows a cross-sectional view of a decking board with channels for allowing the circulation of water / air. Figures 11 show two cross-sectional views of a decking plank with embedded pipes. Figure 12 shows a first embodiment of a junction mechanism for water / air flow decking boards. Figure 13 shows a side elevation view of a threaded collar used in the junction mechanism of figure 12. Figure 14 shows a second embodiment of a junction mechanism. Figure 15 shows a third embodiment of a junction mechanism. Figure 16 shows a fourth embodiment of a junction mechanism. Figure 17 shows a fifth embodiment of a junction mechanism. Figure 18 shows the relationship between the break strength of a core according to an embodiment of the invention as a function of filler loading. Figure 19 shows the relationship between the deflection at break of a core according to an embodiment of the invention as a function of filler loading. Detailed description of the figures Figure 1 shows a cross-sectional view of a plank when formed entirely by a moulding process. Part of the mould generally referenced 1 is formed by a mould skin of plastics material. Part of the mould is shaped to incorporate a relief 2 on the inside of the mould. Part of the mould may have a relief of troughs and peaks of the kind that might be associated with the grain on a wooden plank. Part of the lateral sides 3 of the mould are smooth in order to provide a smooth finish to the corresponding pail of the decking plank or board. Whilst many layer-wise embodiments are envisaged within the scope of the claims that follow the description, in one embodiment, there is at least one layer of elastomer 4 and at least one substantially thicker bulk layer acting as the core 5. Both layers are melded together in the moulding process to avoid the use of adhesives. The boundary between these two primary layers of the board is not a perfect straight line contrary to what the prior art discloses where the layers are separated by a straight boundary line. This is clearly visible in the prior art which discloses a straight line boundary between the previously separately produced extruded support beam and the outer layer of the plank. The elastomer layer 4 may be less than 5 millimetres and preferably about 3 millimetres. In one embodiment, the elastomer is poured or sprayed into the mould followed subsequently by the pouring of a further composition comprising a filler, preferably a particulate filler dispersed within a polymeric matrix; wherein the polymeric matrix is formed from monomers, wherein at least one of the monomers is a polyol. In addition, preferably as part of this further composition a blowing agent is also provided in the mixture. In addition, the moulding process also envisages the provision of randomly oriented fibre sections to the further composition; whereby the fibre sections are multidirectionally retained within a resulting foam of polymer and filler. In other words, at an appropriate time shortly following the completion of the elastomer layer, the further composition is provided to bond with it so that the entirety of layer 5 is formed from polymeric foam comprising both particulate fillers and fibres which combine to provide advantageous bulk and strength whilst bonding to the elastomeric layer. Thus, layer 5 comprises preferably environmentally friendly particulate fillers, porosity due to the foam, and additional strength due to the advantageously disbursed fibres which may be preferably substantially omnidirectionally dispersed in layer 5. Other layers are also envisaged in alternative embodiments. As illustrated in figure 2, the mould would preferably, in optional method step 401, be treated initially with a release agent to facilitate the removal of the plank once the material is set and the subsequent reuse of the mould. One or more additional layers would also be envisaged between the mould and the elastomer. These may include at least one layer of paint such as provided in method step 402. In further embodiments, two paint layers such as provided by method steps 402 and 403 may be provided one being of a first relatively light colour and the other being a relatively dark colour. This succession of paint layers allows the relief on the plank to have contrasting colours to create a so called shadow effect. In order to ensure appropriate colour effect, the process envisages the use of a brush against the initial paint layer or after several paint layers as illustrated by method step 404 in figure 2. As illustrated by method step 405, a further paint layer may also be applied prior to the elastomer which may be selected to be of the main colour of the board. The depth of the paint layers may be of the order of 100 microns or less. A step 406 is envisaged to allow the paint layers to dry and some moisture to evaporate. After an appropriate period, the elastomer layer may be placed on top of the paint layers by spraying or pouring. This may take the form of spraying, as illustrated in method step 407, an elastomer containing fire retardant and levelling the elastomer to ensure appropriate coverage of the main contact surface area of the board. Subsequently, the method optionally envisages levelling out the elastomer although an undulating upper surface may be advantageous for bonding with the further layer once it is deposited on it. The step of levelling is therefore primarily envisaged to ensure that the surface is fully covered by the elastomer. The elastomer may contain appropriate fire retardants. However, in preferred embodiments, the elastomeric layer has no fibre reinforcements and any particulate filler is much less than the percentage of particulate filler in the bulk core layer 5. The further composition which forms bulk core layer 5 is prepared by mixing together polyol, fillers and blowing agent as per the method step 409 of figure 2. Optionally, a pigment is also added to the mixture. Substantially at the time as pouring the mixture into the mould, sections of fibre, in particular individual strands are propelled or blown into the mixture as per method step 411. The fibre sections may be strands of 10 to 50 millimetres. The sections of fibre may be chopped fibre glass sections produced by cutting strands from a roll. The chopped fibre sections may be dropped into an air stream whose turbulence causes the direction of the fibres to be substantially randomised as they are fired into the liquid polymeric mixture. As per method step 412 and 413, the mould is then closed at its upper portion by a metallic plate or lid with air vents to facilitate air to escape to avoid undesirable air pockets. The closed mould is then carried or conveyed in its jig and submitted to high pressure in order to complete the moulding process. After a relatively short period of time under this pressurised environment, the mould is returned to atmospheric pressure and the demoulding operation is carried out by employing a vacuum process to pull the completed board from the mould as per method step 414. The sequence of the method steps in figure 2 may be modified and certain steps are optional. Figures 3a appear to be similar to the inventors own prior publication referenced in the background section, these are however different due to the methodology of production described with reference to figure 1 and therefore the resulting structure of each one of these is fundamentally different. When applying the production method outlined above, a decking plank 7 in cross-section may result where the core 5 may be of the kind described in figure 1. This decking plank has a substantially rectangular cross-section with a core acting as a substantially rigid support beam without being a separate extruded part of plastics material. Although, figure 1 showed the cushioning layer 4 on primarily the bottom of the mould in order to result in the upper surface of the plank when set, figure 3A envisages an embodiment where a cushioning layer 6 (or plurality of layers 4 and 6) entirely encapsulate the plank. On top of the cushioning layer 6, an upper layer 4 is provided which extends only across the top surface of the plank. The embodiment shown in figure 4 shows the upper layer of the embodiment of figure 3a extending at least partially down the sides and / or ends of the plank. Alternatively, the upper layer may extend all down the sides and / or ends of the plank. The support beam forms a strong hard core to support foot fall. The support beam may be made from a polymeric material with a filler material dispersed therein. Figure 3a shows a substantially filled core other than for the porosity of the foam polymer used. By being primarily fully filled, it allows the screwing and retention of a screw into the cushioning and upper layers as well as the support beam or core. Returning to the description of figure 3a, cushioning layer (or layers) 4 and 6 may be a "filled elastomer". The elastomer may preferably be of polyurethane. The filler may be for example, calcium carbonate or fire-retardant fillers. The upper layer 4 may be of a purer polyurethane material so as to have a greater resistance to wear. The upper layer of the decking material incorporates an array of troughs and peaks (i.e. an exposed relief surface) which may also take the shape of the grains of an antique piece of wood or a natural stone, clay tiles or the like. The relief of the softer top surface will also assist in the non-slip properties of the upper layer. The "filled polyurethane" may be blown. As an alternative to the embodiment of figure 3a, figure 3b shows a decking plank 8, with a reinforced core 9 of the kind described with reference to figure 1 but now entirely encapsulated within a single layer of homogeneous cushioning layer material 10, which may be of the "blown" type with "filled polyurethane". In this example, the single cushioning layer 10 forms both the cushioning layer and the upper layer providing the top-surface of the plank on which a user may walk. Side portions 11 and 12 of the reinforced core are covered by the cushioning material. The invention envisages embodiments where only the top surface of the supporting beam and side portions 11 and 12 are covered by the cushioning and / or upper layer material. In a further embodiment, figure 3c shows a reinforced core 14 and an upper top surface only cushioning / upper layer 15 which together form a decking plank 13. The upper layer 15 may be cast on top of the support beam. Figure 3d shows a reinforced core 16 covered by a cushioning / upper layer 17 which entirely encapsulates the reinforced core and includes the exposed relief surface. In this embodiment, the upper surface may be a soft surface when compared to traditional timber. It will nevertheless retain the looks of real wood and will be classified as slipresistant particularly due to the relief. The plastics material used may be selected to have fire-resistant / fire retardant properties. Figure 3e shows a decking plank comprising a reinforced core 18 and a cushioning / upper layer 19 of material applied to the top, sides, and end portion of the reinforced core only. Figure 3f illustrates a decking plank wherein the reinforced core 20 has a cushioning / upper layer 21 on the top surface of the plank. The polymeric material used may be selected to have fire-resistant / fire retardant properties. Figure 5 shows a decking plank generally referenced 204 with a hard reinforced core 205 which may be formed in a mould as per the method of figure 1 with the addition of a number of longitudinal troughs 206. Over the top and side surfaces of the hard reinforced core, there is provided a softer walking surface 207. The harder core may be moulded onto the softer "face". As can be seen in figure 6, trough 206 is closed towards the ends such as end 208. Figure 5 also shows that upper layer 207 also covers the end as well as the sides in this embodiment. Figure 7 shows a further decking plank generally referenced 209 with side grooves 210 and 211. The grooves may be located in one of both sides to accommodate hidden fixings. This embodiment may comprise a reinforced core of the same kind as described with reference to figure 1. Furthermore, the covering of the decking plank may preferably have a Shore factor (A) within the range of around 20 to around 90 Shore (A). Since the reinforced core is provided after the elastomeric layer, it may be possible to also add electrical components or ducts into the reinforced core to achieve not only enhanced strength of the reinforced core but to provide protection of the components which are effectively planted into the reinforced core. The mould may be provided with appropriate shapes to mimic antique wood, stone or terracotta tiles and to indicate the locations for inserting screws. Other suitable mould configurations may be envisaged. It is also envisaged that a conduit or duct such as a hollow tube may be cast in with the layers of plastics covering to allow heating cables to be slid through after the decking plank is formed. Figures 8a and 8b show two portions of two decking planks where the projections of decking plank 212 such as projections 213 and 214, are sized and shaped to fit into corresponding recesses 215 and 216, located on the side of decking plank 217. Projections such as projection 213 incorporates lateral wings 218 and 219, which allow the projection to be locked in place when forced into a recess such as recess 216 where corresponding side cut-outs such as cut-out 220 are provided. In this embodiment, plank 217 incorporates a cushioning / upper layer 221 of polyurethane of a thickness selected within the range 2 to 7 mm. Figure 9 shows two planks of the kind shown in figure 8a and a T-shaped member for insertion into apertures in the sides of the planks in order to secure them together in a so-called invisible manner. Whilst the previous embodiments envisage in particular the use of resistance heating, it is also envisaged to use fluid heated decking such as water heated decking or hot air heated decking. It is envisaged that the decking boards incorporate pipes or an extruded hollow support that can not only support the board but act as a water / air manifold. Figure 10 shows a board 301 with a reinforced core region 302 of the kind described in figure 1 with a number of tunnels to commit the flow of liquid or air so that the board can act as a heat exchanger. The core region is encapsulated in cushioning layer 303 which is made from resin and incorporates a relatively soft upper layer 304. Figures Ila and b show two further embodiments of a heated decking board where pipes are cast or moulded into the resin of the reinforced core which may be of the kind described in figure 1 and manufactured following the methodology of figure 2. The board of figure 1 la shows round pipes 305 whereas the board of figure 1 lb incorporates square pipes 306. A wide variety of junction mechanisms are envisaged between neighbouring pipes or boards. For example, figure 12 shows two boards 307 and 308 supported on a joist at a junction region where a threaded collar 309 is incorporated. The threaded collar incorporates a flange 310 as shown in figure 13. It also incorporates threads on either side of the flange 310. Said threads on each side of the flange are envisaged to meet with hollow cores of two neighbouring boards at the same time. The flange may be faceted in order to allow screwing in with ease by the use of a spanner. Figure 14 shows a further embodiment of the junction mechanism between two neighbouring boards 311 and 312. Each board incorporates a cast in connector 313 and 314 which permit a water tight attachment to a short tube which is slotted between the connectors. Figure 15 shows a further junction mechanism where encapsulated pipes or a hollow extruded support is envisaged and the connector is in the form of a tube 315 with an arrangement of O-rings such as O-ring 316 which are sized and shaped to provide a water tight attachment between the two decking boards. Figure 16 shows two neighbouring boards 317 and 318 and a tube 319 which is simply glued into the channels provided in each decking board. Figure 17 shows the ends of manifold pipes with greater diameters at their connecting extremities in order to locate a pipe 320 which may be glued into position. It is envisaged that the connector pipes may or may not be flexible. The invention also envisages that the fluid flowing in the decking boards may either be heated or cooled in order to act either as a heater or as a cooler. The invention envisages that optionally the decking may be located around a swimming pool in the summer and a pump may be positioned between the decking boards and the water of the swimming pool so that the decking boards may be cooled and simultaneously the water of the swimming pool may be heated by the arrangement. Plastic pipes (possibly 2) cast in the cushioning layer may act as both a support beam as well as a fluid conduit. Figure 18 shows the relationship between the break strength of a polymeric core comprising a limestone filler dispersed therein as a function of the amount of filler loading per 1000 g of polyol used to form the polymeric material. Similarly, figure 19 shows the relationship between the deflection at break of a polymeric core comprising a limestone filler dispersed therein as a function of the amount of filler loading per 1000 g of polyol used to form the polymeric material. The data points shown in Figures 18 and 19 represent an average of a plurality of repeat measurements. All measurements were performed using a Mecmesin MultiTest-i twin column force tester on a sample of the core having dimensions of 250 mm x 32 mm x 50 mm (length x height x width). To obtain the break strength data for Figure 18, the sample was placed into the Mecmesin Multi-Test 25-i machine with a point load positioned halfway (100 mm) between two supports (e.g. the supports are 200 mm apart), wherein the point load is positioned on a top-side of the sample and the two supports are located on an under-side of the sample. The machine was then run at a rate of 250 mm / min (i.e. the point load is moved downwards (e.g. towards the centres) by 250 mm every minute). The break strength is thus determined to be the point at which the load reaches its peak, i.e. the maximum force that causes the sample to break. To obtain the deflection at break data for Figure 19, a three-point flexural test was performed with 200 mm between centres of the points. The deflection at break thus corresponds to the maximum load that is exerted (i.e. the force) resulting in breakage of the sample. As can be seen, as the amount of filler included within the polymeric material increases there is a trend for the core to break at lower forces with a lesser deflection. This follows the conventional understanding that the inclusion of a filler within a polymeric material increases the brittleness (resulting in less flexibility and thus a reduced flex) and reduced strength (e.g. breaks at a lower force). However, as shown by the data, the inventors have surprisingly found that there is a range 5 of filler loading content ranges whereby the break strength and deflection is not substantially affected. Indeed, the break strength even increases. As such, the inventors have advantageously found that filler between 1800 g (per 1000 g of polyol) to 2600 g (per 1000 g of polyol) may be incorporated into the reinforce core without reducing the physical properties of the decking plank below usable levels. Thus, 10 the reinforce core has advantageous bulk strength without requiring to be wholly of polyurethane. Consequently, the plastics content can be reduced whilst providing advantageous physical properties.

Claims

1. A method of producing a plank, comprising the steps of:• providing a mould of a plank with an inner relief corresponding to the configuration of the relief which is to be formed on at least part of the outer surface of a plank;• partially filling the mould with an elastomer;• melding the elastomer with a further composition comprising a filler dispersed within a polymeric matrix; wherein the polymeric matrix is formed from monomers, wherein at least one of the monomers is a polyol; said composition further comprising a blowing agent; and• wherein the weight ratio between the polyol and the filler is from 1:1.8 to 1:2.6.

2. The method of claim 1, further comprising selecting up to substantially 100% of the filler from recycled materials.

3. The method of either claim 1 or claim 2, further comprising the step of providing randomly oriented fibre sections to said further composition; whereby said fibre sections are multi-directionally retained with a resulting foam of polymer and filler; wherein optionally said fibre sections are mixed into an air jet for projecting into the further composition.

4. The method of any one of the preceding claims, wherein the filler is a mineral filler.

5. The method of any one of the preceding claims, further comprising the step of forming the polymeric matrix by mixing polyol monomers with isocyanate monomers which act as a blowing agent.

6. The method of any one of the preceding claims, further comprising the step of mixing the elastomer and a filler.

7. The method of any one of the preceding claims, further comprising the step of placing ducts into the mould.

8. The method of any one of the preceding claims, wherein said mould is enclosed with a metallic lid with air vents to allow air to escape; the method further providing the steps of applying pressure to the filled mould during the setting process prior to demoulding.

9. The method of any of one of the preceding claims, further comprising the step of removing the plank from the mould by suction.

10. A plank comprising:a core acting as a support beam;one or more cushioning layers comprising an elastomer which is retained onto the core; andan upper surface including an exposed relief, wherein the upper surface forms a slip-resistant surface;wherein the core comprises a composition comprising a filler dispersed within a polymeric foam matrix;wherein the polymeric foam matrix is formed from monomers, wherein at least one of the monomers is a polyol; andwherein the weight ratio between the polyol and the filler is from 1:1.8 to 1:2.6.

11. A plank according to claim 10, wherein the core comprises both porosity and randomly oriented fibre sections which are additional to the filler.

12. The plank of either claim 10 or claim 11, wherein up to substantially 100% of the filler is formed from recycled materials.

13. The plank of any one of claims 10 to 12, wherein the filler is a mineral filler.

14. The plank of any one of claims 10 to 13, wherein the polymeric matrix is formed from polyol monomers mixed with isocyanate monomers which act as a blowing agent.

15. The plank of any one of claims 10 to 14, wherein the polymeric matrix is a polyurethane material.

16. The plank of any one of claims 10 to 15, wherein the break strength of the core is greater than 4.6 MPa.

17. The plank of any one of claims 10 to 16, wherein at least one of the one or more cushioning layers comprises an elastomer and a filler.

18. The plank of any one of claims 10 to 17, wherein the core and the one or more cushioning layers are melded together without the use of adhesives.

19. The plank of any one of claims 10 to 18, further comprising a duct located at least partially inside the core.

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