Products, methods and surface structures for preparing an area of hard standing

Abstract

Disclosed herein is a kit of parts for use in preparing an area of hard standing. Methods preparing and using the kit are also disclosed, along with products, compositions and surface structures.

Description

[0001] Products, methods and surface structures for preparing an area of hard standing

[0002] The invention relates to preparing areas of hard standing, such as driveways, pathways, outdoor areas and the like.

[0003] It is known to prepare such areas of hard standing by forming a resin bound layer of particulate material. The particulate material, or aggregate, may be gravel and / or stones and, in particular although not necessarily exclusively, relatively small stone or gravel particles commonly referred to as chippings, gravel or the like. The particulate material can be, for example, provided in different colours for different areas or zones so as to provide an aesthetically appealing surface as well as providing added permanence to the surface which is formed and to provide hardwearing characteristics in comparison to, for example, a surface of grass, soil or the like or loose particulate material which is susceptible to movement due, for example, rainwater flowing across the same, puddles and / or differences in levels of wear on different part of the surface by persons. These resin bound surfaces also typically allow for the drainage of water from the area.

[0004] However, the conventional unitary body which is formed can be susceptible to damage over time especially if the support surface onto which the same has been applied moves, cracks or is generally uneven and / or unstable. A base can be formed on the support surface by digging down and laying a foundation, but it will be appreciated that this laying of foundation or replacement of foundation is a labour-intensive task and can result in material waste when unsuitable preexisting foundation is removed.

[0005] The lack of a suitable base for the unitary body may result in damage to the same. For example, if the unitary body is laid on a damaged existing surface, such as cracked concrete or tarmac, cracks that form in the support surface may propagate through the unitary particulate body. This problem is exacerbated if the unitary body is at least partially bound to the underlying surface.

[0006] Also, if there is no underlying foundation, and the unitary body is laid directly on grass, soil, or other forms of unworked earth, a point load applied to the unitary body will be unsupported and put the unitary body into bending, forming cracks in the same.

[0007] Furthermore, an underlying foundation without adequate water drainage can allow water to be trapped between the foundation and the unitary body, which may affect the adhesion of the resin or form cracks in the body if the water freezes and expands. There is therefore a need for an alternative or improved method of preparing an area of hard standing. In particular, a need for an alternative means for preparing a base for an area of are standing.

[0008] This application is a development with respect to the system disclosed in the applicant’s co¬ pending application GB2501418.4 that claims priority to GB 2401266.8, the contents both of which are incorporated herein by reference.

[0009] In GB2501418.4 & GB 2401266.8, there is provided a surface structure to form an area of hard standing, the surface structure including a particulate body comprising a plurality of particulates; and a resin material which when cured acts to at least partially bond the particulates to each other and wherein the surface structure further includes at least one mesh layer located intermediate the particulate body and a support surface in use.

[0010] While this provides an effective solution, the correct timing of the curing of the resin is essential to ensure that the particulate body and / or the support surface located with the particulate body is adequately bound to ensure the stability of the particulate body. If the resin begins to cure before the particulate material is substantially coated by the resin, there will be insufficient binding of the same.

[0011] Further, it is generally required provide resin in two separate components to be mixed together. When separated, the components do not individually provide binding properties. When combined, the resin begins to cure and must immediately be mixed with the particulate body to bind the same. To ensure the components are adequately mixed, a forced-action mixer must be employed, which is often unavailable to a domestic customer.

[0012] The present application aims to overcome this issue by providing a binding agent / resin that begins curing in a convenient manner to the user. Furthermore, the binding agent / resin is premixed with the particulate body, allowing a domestic user to prepare (at least part of) the area of hard standing without specialised mixing equipment. The mixing of the resin and particulate body may therefore be in a controlled environment that is separate from the location at which the area of hardstanding is to be formed.

[0013] Summary of Invention

[0014] In an aspect of the invention there is provided a kit of parts for use in preparing an area of hard standing, the kit comprising:

[0015] a composition within a sealed container; and a mesh;

[0016] wherein the composition comprises:

[0017] a binding agent comprising a prepolymer comprising functional groups capable of curing by cross-linking; and

[0018] an aggregate mixed with the binding agent.

[0019] The kit may be used for preparing a base (base layer) for an area of hard standing. This may also be referred to as a base course or binder course. These terms are known in the art and are intended to be given their conventional meaning. For example, typical base layers may include a supportive layer that is positioned between the subbase and the final surface layer (e.g. paving, tarmac, concrete or resin bound surfacing). Alternatively, a kit according to the invention may be used for preparing the final surface layer of an area of hard standing

[0020] In some embodiments, a kit according to the invention may be used for preparing both the base layer and the final surface layer of an area of hard standing.

[0021] The term prepolymer is known in the art and is intended to be given its conventional meaning. For example, it includes a substance which has been isolated at an intermediate stage in polymerization that can undergo further reaction, such as cross-linking, to form a cured polymer. The cross-linking may be any conventional means and may occur, for example, upon exposure to moisture or exposure to radiation (such as UV light). Other types of cross-linking may occur upon exposure to heat or oxygen.

[0022] Advantageously, the kit provides a simple and quick solution for preparing a strong area of hard standing that in desirable embodiments is also water-permeable and which can provide a good foundation for the final surfacing, such as resin bound surfacing. As explained above, the kit may also be useful in preparing the final surfacing. In traditional surfacing, a layer of asphalt or concrete is often used to provide a base layer. However, such materials can hinder the flow of water to the subgrade layer thereby increasing the risk of flooding and cracking due to freezing. It is also known to use compacted sand or stones to provide a base layer, however, the sand or stones can shift over time, leading to areas which no longer adequately support the final surface layer. In contrast, the use of the prepolymer in the present invention, which could also be referred to as a resin, provides a curable component that strongly binds the particles of the aggregate to each other (by chemical bonding) and to the supporting mesh to provide a robust area that retains its structure over time, exhibits equivalent or higher compressive strengths than asphalt, but can also be water permeable. Furthermore, the mesh may be a flexible mesh that allows some controlled movement of the area of hard standing. This can allow the area of hard standing to absorb impacts and reduce the likelihood of the area cracking under stress.

[0023] Furthermore, the cross-linking of the prepolymer allows for facile curing (e.g. hardening) of the prepolymer, thereby binding together the aggregate without requiring the introduction of a secondary component (e.g. without a separate hardener component). This can be referred to as a 1K binder. The mixing of this prepolymer with the aggregate also avoids the need to mix the binder and the aggregate together on site. Overall, this allows for the production of a robust base or surface without the need for complex mixing equipment. In this regard, it will be appreciated that typical resin bound materials require onsite mixing of a two-component resin (a base resin and a hardener) which reacts on site to prepare a binder that is subsequently mixed with an aggregate and then laid on the relevant area, e.g. driveway. This requires separately transporting the respective reactants to the site, and considerable care in handling and reacting the relevant components to control the chemical reaction. In comparison the above kit uses a prepared prepolymer which is ready mixed with the aggregate to provide a single composition that is ready to be laid with the mesh and is in a state that can harden quickly making it ideal for conveniently preparing an area of hard standing. In advantageous embodiments this composition can for example be carried by hand in the sealed container to the application site ready for application. As a result, the composition is easier to handle, simpler to apply on site, and able to cure quicker than conventional products, making it ideally suited for use in preparing an area of hard standing for domestic users.

[0024] In a further aspect there is provided a method of preparing an area of hard standing using the above kit of parts, the method comprising the following steps:

[0025] removing at least a part of the composition from the sealed container; contacting the composition with a surface;

[0026] initiating the cross-linking of the prepolymer, thereby binding together the aggregate to form a polymer bound aggregate layer;

[0027] applying the mesh to the composition during the cross-linking of the prepolymer, or to the polymer bound layer; and

[0028] applying a further layer above the mesh.

[0029] It will be appreciated that the surface may be a subbase or subgrade. In some advantageous embodiments, the method further comprises applying a (second) mesh to the surface before contacting the composition with the surface and / or the (second) mesh. Advantageously, this provides a very simple, time effective and convenient method for preparing a robust area of hard standing. Typically, the area of hard standing is a road, driveway, pavement or path.

[0030] It will be appreciated that the further layer could be the top (final) surface of the area or hardstanding, i.e. the surface designed to receive foot or vehicle traffic. Alternatively, the further layer could be an intermediate layer between the polymer bound layer and the top (final) surface layer.

[0031] It is envisaged that the further layer would generally be directly above, e.g. in contact with, the mesh. In some embodiments, it is bonded to the mesh. In alternative embodiments, the mesh may be incorporated in the polymer bound layer and the further surface layer is applied to the polymer bound layer.

[0032] It is not intended that the method above be limited by the order of the steps. For example, the cross-linking of the polymer may be initiated before, or at substantially the same time as, contacting the composition with the surface, or could occur after. Indeed, initiating the cross¬ linking the prepolymer may occur when removing at least a part of the composition from the sealed container, such as by exposing a prepolymer to moisture in the atmosphere, or UV light, at the implantation site. As stated, the mesh can be applied to the composition while the prepolymer is cross-linking (curing) and therefore may become bond to, or integral with, the polymer bound layer. Alternately, it could be applied to the polymer bound layer (i.e., the layer after curing). The top surface layer may also be applied during the cross-linking of the prepolymer. This may advantageously lead to a monolithic structure.

[0033] In a further aspect there is provided a method of preparing an area of hard standing using the above kit of parts, the method comprising the following steps:

[0034] applying the mesh to a surface (e.g. a subbase or subgrade)

[0035] removing at least a part of the composition from the sealed container; contacting the composition with the mesh; and

[0036] initiating the cross-linking of the prepolymer, thereby binding together the aggregate to form a polymer bound aggregate layer

[0037] In a further aspect there is provided the use of the above kit in preparing an area of hard standing. In one embodiment, the use of the above kit in preparing a base layer for an area of hard standing, the base layer suitable for receiving a top (final) surface layer. It will be appreciated that this use can comprise at least some of the steps of the methods described herein.

[0038] In a further aspect there is provided a method of preparing the above kit of parts, the method comprising:

[0039] preparing a binding agent by reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer such that it forms the prepolymer with functional groups capable of curing by cross-linking;

[0040] mixing the binding agent with an aggregate to provide the composition; sealing the composition within the container; and

[0041] providing a mesh.

[0042] In a further aspect there is provided a product, for example a product for preparing an area of hard standing, the product comprising a composition within a sealed container; wherein the composition comprises:

[0043] a binding agent comprising a prepolymer comprising functional groups capable of curing by cross-linking; and

[0044] an aggregate mixed with the binding agent.

[0045] The composition may be for use with a mesh. For example, it may be configured for use with a mesh.

[0046] In a further aspect there is provided a method of preparing the above product, the method comprising:

[0047] preparing a binding agent by reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer such that it forms the prepolymer with functional groups capable of curing by cross-linking;

[0048] mixing the binding agent with an aggregate to provide the composition; and sealing the composition within the container.

[0049] In a further aspect, there is provided the use of the above product in preparing an area of hard standing. In a further aspect of the invention there is provided a composition, e.g. a composition for preparing an area of hard standing, suitable for use in the kit of parts and product described above and herein, the composition comprising

[0050] a binding agent comprising a prepolymer comprising functional groups capable of curing by cross-linking; and

[0051] an aggregate mixed with the prepolymer.

[0052] In a further aspect, there is provided the use of the above composition in preparing an area of hard standing.

[0053] In a further aspect, there is provided an area of hard standing formed using the kit of parts, product or composition described above.

[0054] In a further aspect, there is provided a prepolymer for use preparing an area of hard standing, the prepolymer capable of curing by crosslinking when exposed to moisture and binding together an aggregate,

[0055] wherein the prepolymer is a polyurethane derived from the reaction of a diisocyanate with a polyether polyol,

[0056] wherein the diisocyanate is selected from methylene diphenyl diisocyanate (MDI), methylene 4,4‘-biscyclohexylisocyanate (HDMI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), or combinations thereof; and wherein the prepolymer comprises from 1g to 20g unreacted isocyanate groups per 100g of prepolymer. Preferably, the polyether polyol is a trifunctional polyether polyol (e.g. a polyether triol). The amount of unreacted isocyanate groups can be determined in accordance with Method A of EN ISO 14896:2009 (further described herein).

[0057] In a further aspect, there is provided the use of the prepolymer immediately above for binding an aggregate. In a further aspect, there is provided the use of the prepolymer immediately above for preparing area of hard standing. For example, there is provided the use of the prepolymer immediately above with an aggregate for preparing an area of hard standing.

[0058] Embodiments of the various aspects of the invention are described in the application. For the avoidance of doubt, it will be appreciated, where appropriate, that any embodiments as described herein in relation to one aspect of the present invention will also apply to the other aspects of the present invention.

[0059] Binding Agent

[0060] In any of the aspects or embodiments described herein, the prepolymer comprising functional groups capable of curing by cross-linking may be a prepolymer comprising functional groups capable of curing by cross-linking when exposed to moisture and / or exposed to UV light.

[0061] In preferred embodiments, the binding agent comprises a prepolymer comprising functional groups capable of curing by cross-linking when exposed to moisture.

[0062] In particularly preferred embodiments, the binding agent comprises a prepolymer comprising functional groups capable of curing by cross-linking when exposed to moisture vapour in the atmosphere.

[0063] Advantageously, the ability to cross-link when exposed to moisture provides a very simple method for curing the prepolymer that can be conducted anywhere. It can even allow for the prepolymer to cure without any additional input. The composition can merely be retained in a dry, or at least substantially dry, condition within the sealed container until it is needed, and then it can be exposed to moisture vapour in the air and / or water can be added deliberately, thereby initiating the cross-linking and the hardening of the prepolymer. This binds together the aggregate and provides a strong material without the need to for any specialist equipment, or the supply of multiple products to the repair site. Indeed, the container could be a bag that is carriable to the desired site, opened and used to repair or reinstate the area of hard standing with minimal effort or cost.

[0064] It will be appreciated that the functional groups capable of curing by cross linking are typically unreacted functional groups, such as NCO. As discussed above, the cross-linking may be any conventional means and may occur, for example, upon exposure to moisture and / or exposure to radiation (such as UV light). Other types of cross-linking may occur upon exposure to heat or oxygen. The skilled person will understand which groups may be suitable to enable such cross-linking under the stated conditions. Functional groups that are able to cross link when exposed to moisture for example include NCO (i.e. isocyanate) groups. Functional groups which may undertake cross-linking when exposed to UV light include unsaturated groups such as alkene groups. In any of the aspects or embodiments described herein, the functional groups of the prepolymer may be isocyanate groups. Advantageously, the use of isocyanate groups has been found to provide effective cross-linking of the prepolymer when exposed to moisture. In particular, isocyanate groups have been observed to result in curing on short time scales (a few hours) to form a strong cured polymer, even in the presence of relatively low levels of moisture, such as moisture within the atmosphere.

[0065] The skilled person will be able to adjust (e.g. tailor) the residual amount of (unreacted) functional groups in the prepolymer by controlling the stoichiometry of the starting reactant mixture used to form the prepolymer. For example, in an example wherein an isocyanate monomer is reacted with a polyol to form the prepolymer, it will be appreciated that adding a stoichiometric excess of isocyanate groups relative to reactive hydroxyl groups will result in a prepolymer which has a predictable amount of unreacted isocyanate groups present in the prepolymer. The amount of excess functional groups in the prepolymer can be increased or decreased as desired, depending on the given application and the degree of cross-linking that is desired in the final cured product.

[0066] In any aspects or embodiments of the invention described herein, the prepolymer may comprise from 0.1 g to 40g of unreacted isocyanate groups per 100g of prepolymer. The prepolymer may comprise from 1 to 20g of unreacted isocyanate groups per 100g of prepolymer. The prepolymer may comprise from 5g to 20g of unreacted isocyanate groups per 100g of prepolymer.

[0067] The binding agent (which comprises the prepolymer) may comprise from 0.1 g to 40g of unreacted isocyanate groups per 100g of binding agent. The binding agent may comprise from 1 to 20g of unreacted isocyanate groups per 100g of binding agent. The binding agent may comprise from 3g to 15g of unreacted isocyanate groups per 100g of binding agent. Preferably, the binding agent may comprise from 3g to 10g of unreacted isocyanate groups per 100g of binding agent. In particularly preferred embodiments, the binding agent may comprise from 5 to 9g of unreacted isocyanate group per 100g of binding agent.

[0068] The amount of unreacted isocyanate groups (g per 100g) can be determined by titration. In particular, the amount of unreacted isocyanate groups can be determined in accordance with Method A of EN ISO 14896:2009. Full details of the method are provided in the Examples section below. Advantageously, it has been found that by controlling the amount of unreacted isocyanate groups, the viscosity of the binding agent and the amount of cross-linking upon exposure to water can be controlled. It will be appreciated that it is desirable for preparing areas of hard standing that the binding agent has a viscosity that allows it to be readily workable when being applied to the respective surface. A viscosity that remains flowable is advantageous as this will allow the prepolymer to be readily handled when applying the aggregate, so as to be pourable from the container to the surface during use. Furthermore, prepolymers having a desirable viscosity will allow it to be sufficiency flowable that it can coat the aggregate, while still being thick enough that it is retained on the surface of the aggregate. This helps to ensure the prepolymer aggregate mixture remains stable for long periods (i.e. avoiding the aggregate from settling out).

[0069] In some embodiments, the prepolymer is a polyurethane. Alternatively, the prepolymer may be a polyurea.

[0070] The polyurethane prepolymer may be derived from the reaction of a diisocyanate or triisocyanate with a polyol (e.g. triol). Preferably the polyurethane prepolymer is derived from the reaction of a diisocyanate with a polyol. It will be appreciated that the diisocyanate / triisocyanate and the polyol, may be traditional small molecule monomers, or may themselves be polymeric components that act as monomers to form the prepolymer.

[0071] In some embodiments, the polyurethane prepolymer is derived from the reaction of a diisocyanate or triisocyanate with a polyol, wherein the NCO: OH stoichiometric ratio is from 1:1 to 40:1. The ratio may be from 5:1 to 20:1. For example the NCO: OH stoichiometric ratio may be from 7:1 to 15:1. Advantageously, it has been found that working within these ratios limits to amount of polymerisation leadings to a prepolymer that has a desirable amount of unreacted functional groups, and can easily cured to a fully hardened state, while remaining a thick liquid that can coat the aggregate.

[0072] In some embodiments, the diisocyanate or triisocyanate is an aromatic diisocyanate.

[0073] In some, the diisocyanate is selected from: 2-ethylene diisocyanate; 1,6-hexylene diisocyanate; lysine diisocyanate; bis(2-isocyanatoethyl) fumarate; 1,4-cyclohexylene diisocyanate; methylcyclohexylene diisocyanate; 2,2,4-trimethyl-1,6-hexylene diisocyanate; 2,6-tolylene diisocyanate; 4,4'-diisocyanatodiphenyl ether; 4,4'-diisocyanatodiphenylmethane; 3,3'-dichloro-4,4'-diisocyanatodiphenylmethane; 4,4-diphenyl diisocyanate; 4,4'-diisocyanatodiphenyl; 3,3'-dimethyl-4,4’-diisocyanatodiphenyl; 2,2-dimethyl-4,4'-diisocyanatodiphenyl; 3,3'-dimethoxy-4,4'-diisocyanatodiphenyl; 2,2'-dichloro- 5,5'-dimethoxy-4,4'-diisocyanatodiphenyl; 3,3'-dichloro-4,4'-diisocyanatodiphenyl; 1,3-diisocyanatobenzene; 1,4-diisocyanatobenzene; 1,2-naphthylene diisocyanate; 4-chloro-1,2-naphtylene diisocyanate; 4-methyl-1,2-naphthylene diisocyanate; 1,3-naphthylene diisocyanate; 1,4-naphthylene diisocyanate; 1,5-naphthylene diisocyanate; 1,6-naphthylene diisocyanate; 1,7-naphthylene diisocyanate; 1,8-naphthylene diisocyanate; 4-chloro-1,8-naphthylene diisocyanate; 2,3-naphthylene diisocyanate; 2,7-naphthylene diisocyanate; 1,8- dinitro-2,7-naphthylene diisocyanate; 1-methyl-2,4-naphthylene diisocyanate; 1-methyl-5,7- naphthylene diisocyanate; 6-methyl-1,3-naphthylene diisocyanate; 7-methyl-1,3-naphthylene diisocyanate; p-phenylene diisocyanate; toluene diisocyanate; methylene diphenyl diisocyanate (MDI); polymethylene polyphenyl isocyanate; bitolylene diisocyanate;

[0074] Tetramethyl-m-xylylene diisocyanate; m-tetramethyl-xylylene; hexamethylene diisocyanate; 1,6-diisocyanato-2,2,4,4-tetra-methylhexane; 1,6-diisocyanato-2,4,4-trimethyl-hexane; trans- cyclohexane-1,4-diisocyanate; 1,3-bis(isocyanato-methyl)cyclohexane; 3-isocyanato-methyl-3,5,5-trimethylcyclo-hexyl isocyanate; dicyclohexylmethane diisocyanate, derivatives therefrom, or combinations thereof.

[0075] In preferred embodiments, the diisocyanate is selected from: methylene diphenyl diisocyanate (MDI), methylene 4,4’-biscyclohexylisocyanate (HDMI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), derivatives therefrom, or combinations thereof.

[0076] In particularly preferred embodiments, the diisocyanate is methylene diphenyl diisocyanate (MDI). Advantageously, including MDI in the prepolymer has been found to provide a composition which cures quickly allowing for quick production of the resin bound layer.

[0077] In alternative embodiments, the diisocyanate is hexamethylene diisocyanate (HDI).

[0078] Advantageously including HDI in the prepolymer has been found to provide a composition which has a high resistance to UV degradation.

[0079] In some embodiment the polyol may be selected from ethylene glycol; propylene glycol; trimethylolpropane; trimethylolethane; 1,2-propanediol; 1,4-butanediol; diethylene glycol; polyoxypropylene triols; dihydroxy polyethers; trihydroxy polyethers; poly (tetramethylene glycol); poly (ethylene glycol); poly (propylene glycol); pentaerythritol

[0080] poly (caprolactone diol); polyether / polyester polyol / hybrids; polyester diols extended with propylene oxide; polyether triols; derivatives therefrom, or combinations thereof. In some embodiments, the polyol comprises primary hydroxy groups. Advantageously, primary hydroxyl groups provide high reactivity, which can provide an increased cure rate for the resultant prepolymer.

[0081] In some embodiments, the polyol has two reactive hydroxyl groups (a difunctional polyol / diol), three reactive hydroxyl groups (a trifunctional polyol / triol) or four reactive hydroxyl groups (a tetrafunctional polyol / tetrol).

[0082] In preferred embodiments, the polyol is a trifunctional polyol (e.g. a triol). Advantageously, trifunctional polyols have been found to provide a system that cures quickly and has increased tensile strength compared to a difunctional polyol. Without wishing to be bound by theory, it is believed that trifunctional polyol provides a branched system that presents more terminal hydroxyl groups and provides a 3D network with higher crosslink density.

[0083] Alternativity the polyol may be a difunctional polyol (diol).

[0084] In some embodiments, the polyol may be a polyether polyol. Advantageously, the use of a polyether functionality has been found to provide improved physical properties to the final repaired area of hard standing, including moisture / water resistance, rebound and resilience strength, and improved flexibility.

[0085] The polyether polyol may comprise a poly(alkylene glycol) (PAG), for example a poly(C2-6 alkylene glycol). The C2-6 alkylene group may comprise ethylene and / or propylene. The polyether polyol may comprise the polymerisation product of ethylene oxide and / or propylene oxide. The polyether polyol may comprise (or may be) a polyethylene glycol (PEG) or a polypropylene glycol (PPG). The polyether polyol may comprise (or may be) a copolymer of ethylene oxide and propylene oxide, such as a block copolymer; polyethylene glycol (PEG); and / or polypropylene glycol (PPG).

[0086] Alternatively, the polyol may be a polyester polyol, or a phenol-formaldehyde resin.

[0087] In some embodiments, the polyol is a trifunctional polyether polyol.

[0088] In some embodiments, the polyol has a hydroxyl number of 160 mg KOH / g or lower, as measured in accordance with DIN 53240. Full details of the method are provided in the Examples section below. The polyol may have a hydroxyl number of 80mg KOH / g or lower. For example, the polyol may have a hydroxyl number of 40 mg KOH / g or lower. Advantageously using a lower hydroxyl number has been found to provide a binding agent that is more flexible, easier to manipulate and resistant to weathering.

[0089] In some embodiments, the polyol has a viscosity of around 1000 mPa·s or less measured at 25 degrees Celsius in accordance with DIN EN 12092.

[0090] In some embodiments, the polyol has a density of 1.2 g / cm or less measured in accordance with DIN 51 757 at a temperature of 25°C.

[0091] In some embodiments, the binding agent consists of the prepolymer (i.e. the binding agent is the prepolymer). In other embodiments, the binding agent comprises other components with the prepolymer. Suitable additional components may for example include one or more of diluents, or dyes. Accordingly, the binding agent may comprise the prepolymer in an amount of from 70% to 100% by weight. For example, the binding agent may comprise the prepolymer in an amount of from 80% to 100% by weight.

[0092] In some embodiments, the binding agent further comprises a polymerisation suppressant. An example suppressant is benzoyl chloride but other compounds could also be used. The suppressant may be present in the binding agent in an amount from 0.001% to 0.1% by weight of the binding agent. Advantageously the suppressant can slow down / supress the premature polymerisation / cross-linking of the prepolymer within the sealed container, allowing for longer shelf life.

[0093] In some embodiments the binding agent further comprises kerosene. Advantageously, the presence of kerosene reduces the viscosity of the binding agent and makes the overall composition easier to compact. If the kerosene is present in the binding agent, it may be in an amount less than 15% by weight of the binding agent.

[0094] In some embodiments, the binding agent further comprises other components such as moisture scavengers and / or diluents.

[0095] In some embodiments the binding agent further comprises one or more UltraViolet (UV) stability additives.

[0096] In some embodiments, the binding agent is present in the composition in an amount from 2 to 20 % by weight. The binding agent may be present in the composition in an amount from 3% to 10% by weight. For example, the binding agent may be present in the composition in an amount from 4 to 9% by weight. Advantageously, these amounts of binding agent have been found to strongly bind together the aggregate, while still ensuring that the sufficient aggregate in the composition to provide the area of hard standing with high strength properties. The use of these amounts of binding agent have also been found to allow for an area of hard standing with desirable water permeability.

[0097] In some embodiments, the binding agent has a viscosity of from 100 mPa.s to 10,000 mPa.s measured in accordance with ISO 2555:2018 at 25 degrees Celsius and at 1 atm. The binding agent may have a viscosity of from 1,000 mPa.s to 6,000 mPa.s. The viscosity may be measured using a Brookfield-type rotational viscometer. Providing a viscosity that allows for the binding agent to coat and suspend the aggregate such that they remain mixed over extended periods of time is advantageous because the product can be ready to use immediately once the sealed contained is opened without any need for further mixing.

[0098] Coating of the aggregate can also help ensure that all of the aggregate is sufficiently bound leading to a strong repair / reinstatement of the area of hard standing.

[0099] Accordingly, in some embodiments the aggregate remains suspended in the binding agent for at least 10 days under gravity at a temperature of 25°C. It will be appreciated that this can be achieved by controlling the viscosity of the binding agent.

[0100] In some embodiments, the composition comprising the binding agent has a working time, during which the same can still be sufficiently fluid to be worked, of from 5 mins to 5 hours at a temperature of 20 °C and humidity of 50%.

[0101] Aggregate

[0102] In some embodiments, the aggregate is present in the composition in an amount greater than 10% by weight, such as greater than 50% by weight.

[0103] Typically, the aggregate is present in the composition in an amount of from 80 to 98 % by weight. The aggregate may be present in the composition in an amount of from 90% to 97% by weight. For example, the aggregate may be present in an amount of from 91 to 96% by weight. Advantageously, these amounts of aggregate have been found to provide a high strength final material (i.e. a high strength area of hard standing).

[0104] Accordingly, in exemplary embodiments, the aggregate is present in the composition in an amount of from 80 to 98 % by weight of the composition and the binding agent is present in the composition in an amount from 2 to 20 % by weight of the composition. In other exemplary embodiments, the aggregate is present in the composition in an amount of from 90 to 97 % by weight of the composition and the binding agent is present in the composition in an amount from 3 to 10 % by weight of the composition.

[0105] in some embodiments that water content of the aggregate is less than 1 % by weight of the aggregate. That water content of the aggregate may be less than 0.1 % by weight. For example, the water content of the aggregate may be less than 0.05% by weight. The water content of the aggregate may be determined by ASTM C566 (Total Evaporabie Moisture of Aggregate by Drying).

[0106] It will be appreciated that the binding agent should ideally be substantially absent of any water or moisture (e.g. no water or moisture) so as to avoid premature curing / cross-linking before delivery to the application site, e.g. prior to placing in, or whilst being stored or transported in the sealed container. Accordingly, in some embodiments the water content of the composition is less than 1% by weight, e.g. less than 0.5 % by weight. The water content of the composition may for instance be less than 0.1% by weight of the composition. For example, the water content of the composition may be less than 0.05% by weight of the composition.

[0107] In some embodiments, the water content of the composition may be less than 0.04% by weight of the composition.

[0108] Minimising the water content of the aggregate, and of the composition, allows for the prepolymer to remain in its unreacted form until it is deliberately exposed to moisture (e.g. by exposure to the atmosphere or by deliberate application of water). This prevents premature hardening of the composition and provides a product with a long shelf life, allowing it to be packaged, sold, and transported to the desired site whilst still remaining workable until curing / cross-linking is required at the installation site.

[0109] In some embodiments, the aggregate comprises an igneous or metamorphic rock or a mineral such as quartz. In preferred embodiments, the aggregate comprises, optionally consists of, quartz. The aggregate may have a hardness on the Mohs scale of 6 or greater.

[0110] In some embodiments, the aggregate comprises a mixture of size grades. In particular, the aggregate may comprise (or may have been formed from) a mixture of 5 to 20 mm, such as 5 to 10 mm, aggregate and 1 to 5 mm aggregate. Advantageously, the use of aggregate sizes above 1mm has been found to be compatible with the mesh and provide a final material that is water permeable. For avoidance of doubt, the above grades of aggregate are standard terms of the art and are intended to be given their normal meaning. For instance, a 5 to 20 mm aggregate refers to an aggregate that has been obtained by sieving through screens that have mesh with apertures of 5 and 20 mm.

[0111] in some embodiments, the aggregate comprises from 60 % to 95 % by weight of 5 to 20 mm, preferaby 5 to 10mm, aggregate and from 5 % to 40 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0112] In some embodiments, the aggregate comprises from 70 % to 95 % by weight of 5 to 20 mm, preferably 5 to 10mm, aggregate and from 5 % to 30 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0113] In some embodiments, the aggregate comprises from 80 % to 95 % by weight of 5 to 20 mm, preferably 5 to 10mm, aggregate and from 5 % to 20 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0114] In some embodiments, the aggregate comprises from 85 % to 93 % by weight of 5 to 10 mm aggregate and from 7 % to 15 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0115] In alternative embodiments, the aggregate comprises (or may have been formed from) a mixture of 6 to 20 mm, such as 6 to 10 mm, aggregate and 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0116] In some embodiments, the aggregate comprises from 70 % to 95 % by weight of 6 to 20 mm, preferably 6 to 10mm, aggregate and from 5 % to 30 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0117] In some embodiments, the aggregate comprises from 80 % to 95 % by weight of 6 to 20 mm, preferably 6 to 10mm, aggregate and from 5 % to 20 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0118] In some embodiments, the aggregate comprises from 85 % to 93 % by weight of 6 to 10 mm aggregate and from 7 % to 15 % by weight 1 to 5 mm aggregate, wherein the sizes are determined by sieving.

[0119] In some advantageous embodiments, the aggregate does not comprise significant amounts, preferably any, aggregate of less than 1 mm as determined by sieving. For example, over 90 % by weight of the aggregate may have a size of 1 mm or greater as determined by sieving, i.e. more than 90 % by weight of the aggregate would not pass through a screen that has a mesh with apertures of 1 mm. In some embodiments, from 95 to 100 % by weight of the aggregate has a size greater than 1 mm as determined by sieving.

[0120] Advantageously, avoiding small aggregate, prevents a tight compaction of the aggregate and can provide an area of hard standing that is substantially water permeable.

[0121] It will be appreciated that most aggregate is non-spherical, and therefore the size refers the length of the critical width dimension that determines the ability of the aggregate to pass through the mesh of the sieve. For example, it is possible for aggregate with a narrowest dimension of 2mm, but a widest dimension of 6mm to be within the 1 to 5 mm bracket as it will still pass through the 5mm screen if it falls on its narrowest side.

[0122] Accordingly in some embodiments the aggregate comprises, or may have been formed from:

[0123] 80 to 95% by weight aggregate with a size between 5 to 20 mm, preferably 5 to 10 mm, and

[0124] 5 to 20% by weight aggregate with a size between 1 to 5 mm;

[0125] wherein the sizes are determined by sieving.

[0126] The choice of colour of the aggregate used in the mixture is at the discretion of the user and may be dependent on the desired application and installation site. The aggregate may comprise a mixture of different coloured aggregate. The aggregate may comprise a brown coloured aggregate. The aggregate may comprise a grey coloured aggregate. The colour of the aggregate may be the natural colour of the material, e.g. rock, or may result from dying the aggregate the desired colour. The aggregate may be dyed a desired colour.

[0127] In further exemplary embodiments, the aggregate is present in the composition in an amount of from 80 to 98 % by weight of the composition; the binding agent is present in the composition in an amount from 2 to 20 % by weight of the composition; and the prepolymer is polyurethane comprising isocyanate groups capable of curing by cross-linking upon exposure to moisture.

[0128] In another exemplary embodiments, the aggregate is present in the composition in an amount of from 90 to 97 % by weight of the composition and the binding agent is present in the composition in an amount from 3 to 10 % by weight of the composition; and the prepolymer is polyurethane comprising isocyanate groups capable of curing by cross-linking upon exposure to moisture. In further exemplary embodiments, the aggregate is present in the composition in an amount of from 80 to 98 % by weight of the composition; the binding agent is present in the composition in an amount from 2 to 20 % by weight of the composition; the prepolymer is polyurethane comprising isocyanate groups capable of curing by cross-linking upon exposure to moisture; and the binding agent comprises 1g to 20g unreacted isocyanate groups per 100g of prepolymer. The amount of unreacted isocyanate may be calculated according to the method provided herein.

[0129] In further exemplary embodiments, the aggregate is present in the composition in an amount of from 80 to 98 % by weight of the composition; the binding agent is present in the composition in an amount from 2 to 20 % by weight of the composition; and the prepolymer is polyurethane derived from the reaction of a diisocyanate with a polyether polyol that comprises isocyanate groups capable of curing by cross-linking upon exposure to moisture; wherein the binding agent comprises 1g to 20g unreacted isocyanate groups per 100g of prepolymer.

[0130] In some embodiments, the composition further comprises a colouring agent to allow the area of hard standing to have a desired colour.

[0131] Container

[0132] As described above, the compositions described herein may be advantageously transported to the installation site in a container in a form ready for cross-linking at the site. For example, as described above, the composition may be provided within a sealed container.

[0133] It will be appreciated that the reference to “sealed” means that the container is closed and the composition inside the container is substantially unaffected by the environment outside of the container. For example, the container may be substantially air and / or water impermeable. In other words, the container may be substantially airtight and / or moisture sealed. It will be appreciated that limiting the moisture transfer to the composition reduces any premature cross-linking of a prepolymer that cross-links upon expose to water, providing a long shelf life. The container may also block UV light preventing premature cross-linking of a prepolymer that cross-links upon expose to UV light. The container may also stop other methods of initiating cross linking, such as preventing the prepolymer being exposed to heat or oxygen.

[0134] The sealed container may be a bag. The sealed container may be a plastic bag, for example a polyethylene bag. The sealed container may comprise a barrier material which provides resistance to the permeation of moisture through the container (i.e. a low moisture transfer rate). For example, the container may comprise a metallic or metallised layer, such as a layer of aluminium.

[0135] In some embodiments the container is a bag that comprises a plastic material, such as polyethylene, and further comprises aluminium. In particularly advantageous embodiments, the bag is a composite comprising polyethylene, aluminium and nylon.

[0136] In some embodiments, the composition is stored within the sealed container in an environment, or atmosphere, that is free, or substantially free, from moisture. For example, the composition could also be stored under dry air. In preferred embodiments, the composition is stored in an inert atmosphere within the sealed container. For example, the composition may be stored under nitrogen. Alternatively, the composition may be vacuum sealed in the container. Advantageously, minimising moisture in the container reduces premature cross-linking of the prepolymer, providing a long shelf life to the product.

[0137] Mesh

[0138] The skilled person is familiar with suitable meshes that could be used in prepare areas of hard standing. Suitable meshes provide structural reinforcement, i.e. a structural reinforcement mesh (SRM). Advantageously, the mesh may provide a lateral restraint which spreads loads that are applied to the area of hardstanding.

[0139] In some embodiments the mesh is flexible. For example, the mesh may be a plastic mesh or a rubber mesh. The mesh may comprise polyester and / or polyvinyl chloride. Preferably the mesh comprises multifilament polyester yarns, optionally the yarns are coated with polyvinyl chloride (PVC). Advantageously, the polyvinyl chloride coating can provide UV resistance and increase durability to the mesh.

[0140] The mesh may be malleable to allow it to conform to the stones in a sub-base.

[0141] The mesh may have a thickness of from 0.25 mm to 2mm. In some embodiments, the thickness is from 0.5 mm to 1.5 mm.

[0142] In some embodiments, the mesh is configured in a knitted grid structure formed by intersecting strands. The strands may be formed of high-tenacity multifilament polyester yarns that are coated with PVC, such as black PVC, which provides UV resistance and increased durability to the mesh.

[0143] The mesh may have openings with a size of from 20 to 70 mm in one direction. For example the mesh may have openings that have a size of from 20 to 70 mm in a first direction and of from 20 to 70 mm in a second direction perpendicular to the first direction.

[0144] In preferred embodiments, the mesh has openings that have a size of from 40 to 55 mm in a first direction and of from 40 to 55 mm in a second direction perpendicular to the first direction.

[0145] The openings may allow the aggregate to lodge in the apertures, creating a mechanically stabilised layer. The aggregates in the apertures of the mesh may also bond to the surface below (e.g. the sub-base).

[0146] Accordingly, in some embodiments, the mesh may be a 40 x 40 mm mesh, a 45 x 45 mm mesh, a 50 x 50 mm mesh, or a 55 x 55 mm mesh.

[0147] The openings in the mesh may be square. Alternatively, they may be other shapes, such as rectangular, or triangular.

[0148] In advantageous embodiments, there are at least two mesh layers in the final area of hard standing. Either, or both, of these mesh layers may be the mesh as described above. As discussed below in relation to the method of preparing an area of hard standing, the presence of two mesh layers has been found to provide a more stable and durable area of hard standing.

[0149] Method of preparing an area of hard standing

[0150] As described above, an aspect of the invention relates to a method of preparing an area of hard standing using the above kit of parts (i.e. the kit comprising the composition in a sealed container and the mesh), the method comprising the following steps:

[0151] removing at least a part of the composition from the sealed container; contacting the composition with a surface;

[0152] initiating the cross-linking of the prepolymer, thereby binding together the aggregate to form a polymer bound aggregate layer; applying the mesh to the composition during the cross-linking of the prepolymer, or to the polymer bound layer; and

[0153] applying a further layer above the mesh.

[0154] In some embodiments, the method may further comprises applying a second mesh to the surface prior to contacting the composition with the surface. In such embodiments, the composition is then contacted with the second mesh.

[0155] The second mesh layer applied to the surface (e.g. sub-base) can reduce rutting of the surface (e.g. sub-base), thereby avoiding stresses and / or cracks in the underlying structure. The mesh between the polymer bound layer and the further (e.g. top) layer meanwhile can provide additional flexural strength to resist cracking from external stresses. The two meshes can therefore function in different ways to provide a more stable and durable area of hard standing.

[0156] The first and / or second mesh may bond to, or may be incorporated in, the polymer bound layer. In particularly beneficial embodiment, the first mesh, the polymer bound layer, the further layer, and optionally the second mesh, are all bound together, e.g., there is a monolitihic bond between the top and the bottom of the area of hard standing providing a strong robust area of hard standing.

[0157] The further (e.g. top) layer may be a resin bound surfacing layer (i.e. a layer of aggregate bound by a resin). This may be formed by traditional resin bound surfacing methods (e.g. mixing a (second) resin (either a one- or two-part resin) with a (second) aggregate and applying the mixture above, preferably to, the mesh). Alternatively, the further (e.g. top) layer may be applied by contacting a composition as defined herein (i.e. a composition comprising a prepolymer and an aggregate in a sealed container) to the mesh. In other embodiments, the further (e.g. top) layer is applied by spreading a further aggregate over the mesh and spraying a resin over the further aggregate layer.

[0158] In alternative embodiments, the polymer bound layer forms the top (final) surface layer. In such embodiments, the method of preparing the area of hard standing comprise applying the mesh to a surface (e.g. a subbase or subgrade)

[0159] removing at least a part of the composition from the sealed container; contacting the composition with the mesh; and

[0160] initiating the cross-linking of the prepolymer, thereby binding together the aggregate to form a polymer bound aggregate layer. It will be appreciated that the polymer bound aggregate layer may incorporate the mesh within the bound layer, providing structural reinforming to the layer.

[0161] In some embodiments of the above methods, initiating the cross-linking the prepolymer comprises contacting the composition with moisture. Contacting the composition with moisture may comprise exposing the composition to water vapour in the air. Alternatively, or additionally, contacting the composition with the moisture may comprise adding water to the composition (i.e. deliberately), such as after contacting the composition with the mesh.

[0162] Adding water may be allow for the composition to cross-link quickly, which might be advantageous when the area of hard standing needs to be prepared quickly, e.g. a carriageway of a road. Adding water to the composition in this way may be done by any conventional means. It may for instance involve spraying water onto the composition. It may for instance involve pouring water, or otherwise spreading water, onto the composition.

[0163] In alternative embodiments, initiating the cross-linking the prepolymer comprises exposing the composition to UV light. In other embodiments, initiating the cross-linking the prepolymer comprises exposing the composition to heat. In other embodiments, initiating the cross¬ linking the prepolymer comprises exposing the composition to oxygen.

[0164] Contacting the composition with the surface or mesh can be done by any suitable means. In some embodiments, it involves pouring the composition out of the container onto the mesh. Alternatively, or additionally, it could involve mechanically removing the composition from the container and onto the mesh. Any conventional means may be employed in this regard, such as by shovelling the composition out of the container and onto the mesh.

[0165] The method may further comprise compacting the composition onto the surface or mesh. This can ensure that a high-density composition is applied to the mesh and provide an upper surface which is substantially flat and useable as a base layer for a final surface coating.

[0166] Method of preparation

[0167] As described above, an aspect of the invention relates to a method of preparing the above kit of parts (i.e. the kit comprising the composition in the sealed container and the mesh), the method comprising:

[0168] preparing a binding agent by reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer such that it forms the prepolymer with functional groups capable of curing by cross-linking;

[0169] mixing the binding agent with an aggregate to provide the composition; and sealing the composition within the container; and

[0170] providing a mesh.

[0171] Also described is a method of preparing the above product (i.e. the product comprising the composition in the sealed container), the method comprising:

[0172] preparing a binding agent by reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer such that it forms the prepolymer with functional groups capable of curing by cross-linking;

[0173] mixing the binding agent with an aggregate to provide the composition; and sealing the composition within the container.

[0174] For the avoidance of doubt, all the features described above in relation to the kit, product, composition, or to any of their constituent parts, are also intended to be disclosed in relation to these methods of preparation. However, for completeness, some specific comments and features are also presented below.

[0175] In some embodiments, the method further comprises the step of drying the aggregate prior to mixing the binding agent with the aggregate. In some embodiments, the aggregate is dried to a moisture content of less than 1 % by weight. The aggregate may be dried to a moisture content of less than 0.1% by weight. For example, the aggregate may be dried to a moisture content of from 0.01 % to 0.05% by weight The water content of the aggregate may be determined byASTM C566 (Total Evaporable Moisture of Aggregate by Drying).

[0176] As described above, minimising the water content of the aggregate allows for the prepolymer to remain in its unreacted form until it is deliberately exposed to moisture. This prevents premature hardening of the composition and provides a product with a long shelf life, allowing it to be packaged, sold, and transported to the desired site.

[0177] The aggregate may be dried using a rotary dryer or fluid bed dryer at a temperature of from 50 to 150°C. The aggregate may be heated for 1 to 120 mins, such as 1 to 30 mins.

[0178] However, it will be appreciated that other forms of drying are also possible. In some embodiments, the first monomer is a diisocyanate or triisocyanate and the unreacted functional groups are isocyanate groups. The diisocyanate or triisocyanate may be an isocyanate as defined above in relation to the prepolymer.

[0179] In some embodiments, the second monomer is a polyol. The polyol may be a polyol as defined above in relation to the prepolymer.

[0180] Accordingly, in some embodiments, reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer, comprises reacting a diisocyanate or triisocyanate with a polyol, wherein the diisocyanate or triisocyanate is in excess compared to the polyol. In particular, wherein the isocyanate groups (NCO) of the diisocyanate or triisocyanate are in stoichiometric excess compared to the hydroxy (OH) groups of the polyol.

[0181] In this regard, it will also be appreciated that the terms first monomer and second monomer are not intended to refer only to small molecular monomers but encompasses short polymeric components that can act as monomers in their own right, e.g. a trifunctional polyether polyol.

[0182] In some embodiments, reacting a first monomer with a second monomer, wherein the first monomer is in excess compared to the second monomer comprises reacting a diisocyanate or triisocyanate with a polyol, wherein the stoichiometric ratio of NCO groups to OH groups in the reaction is from 1:1 to 40:1. The stoichiometric ratio of NCO groups to OH groups in the reaction may be from 5:1 to 20:1. For example, the stoichiometric ratio of NCO groups to OH groups in the reaction may be from 7:1 to 15:1.

[0183] In some embodiments, the water (moisture) content of the polyol is less than 0.5%. The water (moisture) content of the polyol may be less than 0.1%. For example, the water (moisture) content of the polyol may be less than 0.05%. Preferably, the water (moisture) content of the polyol may be less than 0.04%. As described in relation to the aggregate, minimising moisture in the composition is beneficial since the prepolymer cross-links with moisture. Minimising moisture therefore allow for a long shelf-life and prevents premature polymerisation or premature cross linking of the prepolymer.

[0184] As described above in relation to the prepolymer, the first monomer may be a diisocyanate selected from: methylene diphenyl diisocyanate (MDI), methylene 4,4'- biscyclohexylisocyanate (HDMI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), derivatives therefrom, or combinations thereof. In preferred methods, these may be carbodiimide-modified diisocyantes. For example, the first monomer may be a carbodiimide-modified 4,4‘-methyiene diphenyl diisocyanate (MDI).

[0185] Advantageously, the carbodiimide modification lowers the crystallisation temperature allowing it to stay a liquid at room temperature, which allows the material to be stored and used more easily.

[0186] In some embodiments, the method further comprises adding a polymerisation suppressant to the binding agent. An example suppressant is benzoyl chloride, but other compounds could also be used. The suppressant may be present in the binding agent in an amount from 0.001% to 0.1% by weight of the binding agent. Advantageously the suppressant can slow down / supress the premature polymerisation / cross-linking of the prepolymer within the sealed container, allowing for longer shelf life.

[0187] The step of mixing the binding agent with an aggregate to provide the composition may involve mixing the binding agent with the aggregate in amounts required to achieve the amount of each components specified above.

[0188] For example, the binding agent may be mixed with the aggregate in an amount such that it constitutes 2 to 20 % by weight, preferably 3% - 10% by weight, such as 4 to 9% by weight of the composition.

[0189] The aggregate may be mixed with the binding agent in an amount such that it is present in the composition in an amount from 80 to 98 % by weight, preferably, 90% to 97% by weight, such as 91 to 96% by weight of the composition.

[0190] It will be appreciated that the aggregate may be the aggregate as defined above. For example, it may comprise, optionally consists of, a mineral, such as quartz.

[0191] In some embodiments, sealing the composition within the container comprises sealing the composition within the container in an environment free, or substantially free, from moisture. In some embodiments, sealing the composition within the container comprises sealing the composition within an inert atmosphere within the container. In other embodiments, sealing the composition within the container, comprises vacuum sealing the composition within the container. Further description of the invention

[0192] In a further aspect of the invention, there is provided a surface structure to form an area of hard standing, the surface structure including a particulate body comprising a plurality of particulates; and a resin material which when cured acts to at least partially bond the particulates to each other and form a hardened surface structure, said surface structure further includes at least one mesh layer located therein and wherein the said particulate material and resin are premixed and placed in a substantially sealed container for transport to the location of formation of the surface structure.

[0193] Typically the resin is maintained in a substantially fluid condition whilst in the sealed container.

[0194] In one embodiment the resin includes a component that allows the same to cure when exposed to a predetermined amount of moisture, such as when the said container is opened at the location of use. Preferably the amount of moisture in the ambient air at the location at which the surface structure is to be formed. In one embodiment, the component is a polyurethane binder and preferably the component is a 1k polyurethane binder. It will be appreciated that a 1k polyurethane binder is a polyurethane prepolymer and can be the polyurethane prepolymer as defined above.

[0195] In this embodiment, the resin is initially mixed with the particulates which have been dried so as to reduce the moisture of the same to below a predetermined level. Typically when the container is opened and the mixture is exposed to the air at the location at which the structure is to be formed, the resin begins to cure.

[0196] It will be appreciated that the plurality of particulates is an aggregate and may be the aggregate as defined above.

[0197] In this embodiment, the resin is mixed with the particulate material and / or the ballast material at a first location different from the location at which the structure is to be formed.

[0198] The container may be the container as described as described above. In one embodiment the container is a bag and preferably has walls which deter the passage of moisture therethrough from the external environment.

[0199] This provides the advantage that the user can unseal the mixture of the resin and the particulate material and / or ballast material and apply the same to form the surface structure, without carrying out any further steps to begin the curing of the resin. This further provides the advantage that a controlled ratio of resin to particulate / ballast material is achieved by the manufacturer of the mixture, and which can be done under relatively controlled conditions so that the mixture ratio does not need to be determined by the user.

[0200] In one embodiment, the resin includes a further components to allow the surface structure to be formed at a particular geographical location and / or onto a specific type of base.

[0201] In one embodiment the resin is provided to coat the ballast material in a sealed condition prior to the application of the same and / or the resin is provided to coat the particulate material in a sealed condition prior to the application of the same onto the second mesh layer and ballast material layer. In this embodiment, the resin includes a component that allows the same to cure when exposed to a predetermined amount of moisture, preferably the amount of moisture in the ambient air at the location at which the surface structure is to be formed. In one embodiment, the component is a polyurethane binder and preferably the component is a 1k polyurethane binder.

[0202] Description of Figures

[0203] Specific embodiments of the invention will now be described with reference to the following figures, wherein:

[0204] Figure 1 illustrates a section side view of a particulate material reinforced by a first and second mesh layer in accordance with an embodiment of the invention.

[0205] Referring firstly to Figure 1, there is illustrated a cross section of part of a surface structure 2 located on a support surface 4. The support surface 4 in this example is MOT Type 3 which is to be covered by the surface structure 2 to form an area of hard standing.

[0206] The surface structure 2 is comprised of a number of layers which in this embodiment comprise a first SRM mesh layer 6 laid onto the support surface 4. The mesh layer 6 is configured in a knitted grid structure formed by intersecting strands 8. The strands 8 are formed of high- tenacity multifilament polyester yarns that are coated with black PVC, which provides UV resistance and increased durability to the mesh.

[0207] Applied onto the first mesh layer 6 is a ballast material 10 which is coated in a binding resin prior to the application of the same to be spread across the first SRM mesh layer 6. This ballast material 10 is provided of a size and / or thickness suitable for the particular purpose of the area of hard standing and / or size of the particulate material to be used. The ballast material 10 further acts as a suitable level foundation for the second mesh layer 12 to be laid thereon. The second mesh layer 12 is of a similar construction to the first mesh layer 6, and acts to form a foundation for a particulate body 14 to be formed thereon.

[0208] The particulate body 14 is formed of a number of particulates 16 that have been coated with a resin including a component that allows the same to cure when exposed to a predetermined amount of moisture. In this example, the component is a polyurethane binder and the predetermined amount of moisture is the moisture levels in the ambient air at the location at which the surface structure is to be formed. The particulates and resin are provided, premixed to the location of use in one or more sealed containers, such that when the user unseals the container to access the mixture the mixture in order to apply the same onto the second mesh layer 12, the resin in the mixture begins to cure in ambient conditions due to the moisture levels present. Typically the curing to hardened condition takes sufficient minutes or hours so that the mixture remains fluid and workable for a sufficient length of time so as to be applied and the support surface to be formed, spread and flattened and have force applied thereto in order to provide the required configuration of the surface with the mesh embedded therein. This provides the advantage that no further steps are required by the user to trigger the curing of the resin, other than unsealing the container. In this example, the resin includes a 1k polyurethane binder / prepolymer.

[0209] Thus the particulate mixture can be applied from the container onto the upper mesh layer 12 and levelled with the mesh embedded therein before the resin fully cures and the particulate upper layer 14 when hardened forms a unitary body with the second mesh layer 12.

[0210] In exemplary embodiments, the ballast material / aggregate layer 10 and the second mesh layer 12 may be prepared using the kit of the present invention. The kit comprises a composition comprising an aggregate and prepolymer in a sealed container and a mesh. The composition is removed from the sealed container and contacted with a surface, such as a support surface 4, which may optionally have been covered with a mesh 6. Cross¬ linking is initiated, e.g. upon contact with moisture in the atmosphere, to form a polymer bound aggregate layer 10. The mesh of the kit of the invention may then be applied to the composition during cross-linking of the prepolymer or the polymer bound aggregate layer after cross-linking to form mesh layer 12. A further layer, e.g. layer 14, can then be applied. Examples

[0211] Preparation of Pre-Polymer (Binding Agent)

[0212] A trifunctional polyether polyol monomer with a moisture content of 0.05% or below is contacted with a carbodiimide-modified 4,4’-methylene diphenyl diisocyanate (MDI) monomer in a 7:1 to 15:1 NCO: OH stoichiometric ratio to form a mixture. The mixture is agitated until the mixture undergoes a visible change in appearance from substantially transparent to an opaque and / or cloudy white state. The temperature of the mixture is increased to between around 60 °C and around 100 °C for up to 90 minutes or until the mixture visually transitions from an opaque / cloudy white state to a translucent, yellow state. Preferably, benzoyl chloride (0.02 wt%) is added to the mixture, before allowing the temperature of mixture to reduce to between 15 °C and 27 °C, e.g. room temperature. It is preferable for the method, or at least one of the steps of the method, to be performed under an inert atmosphere, such as nitrogen.

[0213] Preparation of Aggregate

[0214] The aggregate is first cleaned to remove any unwanted dust and / or dirt, before reducing the moisture content of the aggregate to between 0.05% and 0.1% by heating the aggregate between 50°C and 150°C for up to 15 mins in a rotary dryer or fluid bed dryer. The aggregate is passed through one or more sieves, such as a stack of sieves of progressively smaller openings, to further remove any remaining dust and / or aggregate particles outside of the desired particle size range.

[0215] Sieve analysis may be utilised to confirm the granularity of the aggregate. For example, the aggregate may be passed through a vibrating or electromagnetic sieve shaker to separate the aggregate into various size ranges. The vibrating or electromagnetic sieve shaker may comprise a stack of one or more sieves, wherein the mesh size of each sieve other than the top sieve comprising the stack is smaller than the sieve directly above.

[0216] In an exemplary method of sieve analysis, an electromagnetic sieve shaker comprises three sieves stacked vertically with mesh sizes from top to bottom of 10 mm, 5 mm and 1 mm, respectively. The aggregate is transferred to the top sieve of the sieve stack and vibration is applied for at least 5 minutes. The contents of each sieve are then weighed to determine the percentage of aggregate within each particle size range in respect of the total aggregate weight. Preparation of a Composition

[0217] A prepolymer was prepared as described above comprising 44.99 wt% trifunctional polyol, 54.99 wt% MDI and 0.02 wt% benzoyl chloride. The mixing occurred over a period of at least 30 minutes with periodic agitation. The temperature of the mixture was then reduced to between 15 °C and 27 °C, e.g. room temperature.

[0218] An aggregate blend was prepared as described above comprising 85% by weight 5-10 mm quartz, and 15% by weight 1-5 mm quartz. The aggregate blend was then mixed with the pre¬ polymer binding agent in a ratio of 23:2 weight ratio using a ribbon blender at 15rpm for up to 10 minutes under a nitrogen atmosphere or dry air.

[0219] The resultant composition was then sealed in a bag within a nitrogen atmosphere. The bag comprised a polyethylene, aluminium and nylon composite material.

[0220] Determination of Isocyanate Content

[0221] The isocyanate content of the prepolymer was determined according to EN ISO 14896. The method involved titration following the reaction of the prepolymer with dibutylamine. HCI was used as a titrant and TRIS (tris(hydroxymethyl)aminomethane) was used as a standard. A detailed description is provided below.

[0222] Titre

[0223] 420 mg TRIS was weighed into a titration vessel. 20 mL of deionized water and 50 mL acetone were added. After a pause of 20 s, the solution was titrated with HCI (1.0 mol / L aqueous solution) until the first equivalence point.

[0224] The titre of the titrant (HCI) was then determined based on Equation 1 below:

[0225]

[0226] × c(HCl) × MS

[0227] Equation 1

[0228] Wherein: f: Titre of the selected titrant;

[0229] ms: Mass of standard (TRIS) in mg;

[0230] VEP-I: Titrant consumption until the first equivalence point in mL;

[0231] c(HCI): Concentration of the titrant (HCI) in mol / L; and

[0232] Ms: Molecular weight of the standard (TRIS) - 121.14 g / mol

[0233] Sample testing

[0234] Around 2 g of sample was weighed out and dissolved in 30 mL of toluene. 18.0 mL of reaction solution (1 mol / L dibutylamine in toluene) was added and allowed to react for 10 min while stirring. 30 mL of acetone was then added and the excess of dibutylamine was back titrated with HCI (1 mol / L aqueous solution).

[0235] Blank

[0236] A blank sample was treated and titrated in exactly the same way as the actual sample but without any sample.

[0237] The isocyanate content was then determined based on Equation 2 below:

[0238] Mrn " WPI)Xf * c(HCI) * MA

[0239]

[0240] TOxnis

[0241] Equation 2

[0242] Wherein:

[0243] NCO: Isocyanate content of the sample in g isocyanate / 100 g;

[0244] VEPL Titrant consumption until the first equivalence point in mL in the sample testing; VBLANK: Used titrant in mL for the Blank back titration;

[0245] c(HCI): Concentration of the selected titrant (HCl) in mol / L - 1.0 mol / L;

[0246] f: Titre of the selected titrant - as determined in Equation 1;

[0247] MA: Molecular weight of NCO - 42.02 g / mol;

[0248] ms: Sample size in g; and

[0249] 10: Conversion factor for %.

[0250] As will be appreciated, the prepolymer may be capable of reacting with moisture vapour in the air. The testing of the sample was therefore conducted in inert conditions by covering the sample in an inert gas (e.g. nitrogen)

[0251] Determination of Hydroxyl Value

[0252] The hydroxyl value, i.e. the degree of esterification, of the prepolymer was determined according to ASTM E1899. The hydroxyl value is given in milligrams of potassium hydroxide per gram of sample. Tetrabutyl ammonium hydroxide (TBAOH) (0.1 mol / L) in isopropanol / methanol (Φ(MeOH) = 50% (v / v)) was used as a titrant. A 500 mL solution of toluene-4-sulphonyl-isocyanate (TSI) (20 mL) in acetonitrile, referred to as TSI solution henceforth, was made in advance.

[0253] Titre

[0254] 60 mL deionised water was added to approximately 180 mg potassium hydrogen phthalate (KHP). The suspension was stirred for around one minute to dissolve the KHP. The solution was then titrated until the first equivalence point using the titrant. The titre of the titrant (TBAOH) was then determined based on Equation 3 below:

[0255]

[0256] Equation 3 Wherein:

[0257] f: Titre of the selected titrant;

[0258] ms: Mass of standard (KHP) in mg;

[0259] VEPI: Titrant consumption until the first equivalence point in mL;

[0260] c(TBAOH): Concentration of the selected titrant in mol / L; and

[0261] Ms: Molecular weight of the standard (KHP) - 204.22 g / mol.

[0262] Sample

[0263] The required amount of sample to be used was calculated as follows:

[0264] C 4 X

[0265]

[0266] OH expected

[0267] Equation 4

[0268] Wherein:

[0269] ms: Sample size in g; and

[0270] OHVexpected: Expected hydroxyl value.

[0271] The required amount of sample as calculated in Equation 4 was weighed into the titration vessel and dissolved in 10 mL acetonitrile, and the solution was stirred for 30 s. 10 mL TSI solution was added before covering and stirring the mixture. After 5 minutes, 0.5 mL deionised water was added, the lid closed again, and the solution stirred for another 60 s. 40 mL acetonitrile was added, and the solution was titrated until after the second end point with the titrant.

[0272] The hydroxyl value of the sample was then determined based on Equation 5 below: nuv ’ VEPI ) x f x c(TBAOH) x MA

[0273] UnV ™ -

[0274]

[0275] Equation 5

[0276] Wherein:

[0277] OHV: Hydroxyl value of the sample in mg KOH / g sample;

[0278] VEP Titrant consumption until the first equivalence point in mL;

[0279] VEP2: Titrant consumption until the second equivalence point in mL;

[0280] c(TBAOH): Concentration of the selected titrant in mol / L;

[0281] f: Titre of the selected titrant - as determined in Equation 3;

[0282] MA: Molecular weight of KOH; here 56.11 g / mol; and

[0283] ms: Sample size in g

[0284] Although the present invention has been described in detail, it should be understood that various changes, substitutions, and alterations are contemplated without departing from the principle and scope of the invention. Accordingly, the scope of the present invention defined herein and particularly the following claims should be interpreted in consideration of the appropriate equivalents. The terms "a", "an" and "the" do not preclude the presence of multiple referents, unless the context clearly dictates otherwise. Optional, optionally, or preferably means that the feature or activity may or may not be present. Either is contemplated. In embodiments, the optional / preferable feature or features may be present. Alternatively, the optional feature or features may not be present. Ranges may be expressed herein as “from” one particular value, and / or “to” another particular value, which is intended to be inclusive of the end-points of the range.

Claims

CLAIMS1. A kit of parts for use in preparing an area of hard standing, the kit comprising:a composition within a sealed container; anda mesh;wherein the composition comprises:a binding agent comprising a prepolymer comprising functional groups capable of curing by cross-linking; andan aggregate mixed with the binding agent2. A kit of parts according to claim 1, wherein the functional groups are isocyanate groups.

3. A kit of parts according to claim 2, wherein the binding agent comprises of from 0.1g to 40g, optionally 1g to 20g, further optionally 3g to 10g, unreacted isocyanate groups per 100g of prepolymer.

4. A kit of parts according to any preceding claim, wherein the prepolymer is a polyurethane, preferably wherein the prepolymer is derived from the reaction of a diisocyanate or triisocyanate with a polyol.

5. A kit of parts according to claim 4 wherein the prepolymer is derived from the reaction of a diisocyanate or triisocyanate with a polyol, wherein the NCO stoichiometric ratio is of from 1:1 to 40:1, preferably from 5:1 to 20:1, such a 7:1 to 15:1.

6. A kit of parts according to claims 4 or 5, wherein the diisocyanate or triisocyanate is a diisocyanate selected from: methylene diphenyl diisocyanate (MDI), methylene 4,4'- biscyclohexyl isocyanate (HDMI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), p- phenylene diisocyanate (PPDI), derivatives therefrom, or combinations thereof; preferably wherein the diisocyanate monomer is methylene diphenyl diisocyanate (MDI).

7. A kit of parts according to claims 4 to 6 wherein the polyol is a trifunctional polyol, preferably a trifunctional polyether polyol.

8. A kit of parts according to any preceding claim, wherein the binding agent has a viscosity of from 100 mPa.s to 10,000 mPa.s, optionally 1,000 mPa.s to 6,000 mPa.s, measured at 25 degrees Celsius in accordance with ISO 2555:2018.

9. A kit of parts according to any preceding claim, wherein the binding agent is present in the composition in an amount from 2 to 20 % by weight, optionally 3% to 10% by weight, such as 4 to 9% by weight.

10. A kit of parts according to any preceding claim wherein the aggregate is present in the composition in an amount from 80 to 98 % by weight, optionally 90% to 97% by weight, such as 91 to 96% by weight.

11. A kit of parts according to any preceding claim, wherein the aggregate comprises:70 to 95% by weight aggregate with a size between 5 to 20mm; and5 to 30% by weight aggregate with a size between 1 to 5mm;wherein the sizes are determined by sieving.

12. The kit of parts product according to any preceding claim, wherein the sealed container is a bag, optionally a bag comprising polyethylene, nylon and aluminium.

13. The kit of parts according to any preceding claim, wherein the composition is stored in an inert atmosphere, such as nitrogen, within the sealed container and / or the composition is vacuum sealed in the container.

14. A method of preparing a kit of parts according to any of claims 1 to 13, the method comprising:preparing a binding agent by reacting a first monomer with a second monomer, wherein the reactive groups of the first monomer are in stoichiometric excess relative to the corresponding reactive groups in the second monomer such that it forms the prepolymer with functional groups capable of curing by cross-linking;mixing the binding agent with an aggregate to provide the composition; sealing the composition within the container; andproviding a mesh.

15. The method according to claim 14 further comprising the step of drying the aggregate prior to mixing the binding agent with the aggregate, optionally wherein the aggregate is dried to a moisture content of less than 1% by weight, preferably less than 0.1% by weight, such as from 0.01% to 0.05% by weight.

16. The method according to claims 14 or 15, wherein the first monomer is a diisocyanate or triisocyanate and the functional groups are isocyanate groups; and the second monomer is a polyol, preferably a trifunctional polyol, such as a trifunctional polyether polyol.

17. The method according to claims 16, wherein the stoichiometric ratio of NCO groups to OH groups in the reaction is from 1:1 to 40:1, preferably from 5:1 to 20:1, such as 7:1 to 15:1.

18. A method of preparing an area of hard standing using the kit according to any of claims 1 to 13, the method comprising the following steps:removing at least a part of the composition from the sealed container; contacting the composition with a surface;initiating the cross-linking of the prepolymer, thereby binding together the aggregate to form a polymer bound layer;applying the mesh to the composition during the cross-linking of the prepolymer, or to the polymer bound layer; andapplying a further layer, preferably a resin bound surfacing layer, above the mesh.

19. The method according to claims 18, further comprising applying a second mesh to the surface prior to contacting the composition with the surface, wherein the composition is then contacted with the second mesh.

20. Use of the kit according to any of claims 1 to 13 in preparing a base layer of an area of hard standing, the base layer being suitable for receiving a top surface layer.

21. A surface structure to form an area of hard standing, the surface structure including a particulate body comprising a plurality of particulates; and a resin material which when cured acts to at least partially bond the particulates to each other and form a hardened surface structure, wherein said surface structure further includes at least one mesh layer located therein and wherein the said particulate material and resinare premixed and placed in a substantially sealed container for transport to the location of formation of the surface structure.

22. The surface structure of claim 21, wherein the resin comprises a 1k polyurethane binder which cures when exposed to the ambient air at the location at which the surface structure is to be formed.

23. The surface structure of claims 22 or 23, wherein the container is a bag with walls which deter the passage of moisture therethrough from the external environment.

24. The surface structure of any of claims 22 to 24, wherein the mesh layer is configured in a knitted grid structure formed by intersecting strands of multifilament polyester yarns coated with PVC.

25. A product for forming an area of hard standing, the product comprising a particulate body mixed with a resin in a sealed container, wherein the resin comprises a polyurethane binder that cures when exposed to moisture levels in the ambient air at the location at which a surface structure is to be formed.

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