Composite sheet material

Abstract

Fabric comprising fibres interlocked by entanglement includes fibers mechanically bonded to reinforcing layer. The entangled fibres are coated with a resinous foundation layer and at least partially i

Description

TECHNOLOGICAL FIELD Examples of the disclosure relate to a composite sheet material and a method of producing a composite sheet material. Some relate to a composite sheet material comprising a foundation layer. BACKGROUND Sheet materials can be formed using hydroentanglement. An arrangement comprising a body of fibres is subjected to high pressure jets of liquid to interlock the fibres together by entanglement. In some instances, the body of fibres may be mechanically bonded to a reinforcing structure during hydroentanglement to provide a sheet material with improved mechanical properties. The surface texture, porosity, and depth of holes in the surface of these materials can vary throughout the sheet material. Where the body of fibres includes a mixture of fibre types, these irregularities can be further exacerbated. BRIEF SUMMARY According to various, but not necessarily all, examples there is provided a composite sheet material comprising: a reinforcing material; a body of fibres, the body of fibres including fibres interlocked with each other by entanglement, and wherein at least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material; a foundation layer comprising a resin, wherein the resin overlays the body of fibres and partially penetrates into the body of fibres; and a coating overlaying the foundation layer. The foundation layer may have a dry coat weight of up to 200 gsm. The foundation layer may have a dry coat weight of up to 120 gsm. The resin of the foundation layer may penetrate on average up to 600 microns into the body of fibres. The resin of the foundation layer may penetrate on average up to 500 microns into the body of fibres. The resin of the foundation layer may penetrate on average up to 300 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 100 microns to 500 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 200 microns to 400 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 250 microns to 500 microns into the body of fibres. The foundation layer may have an average thickness of 100 microns to 500 microns. The foundation layer may have a dry coat weight of up to 120 gsm and the coating may have a dry coat weight of at least 150 gsm. The foundation layer may have a dry coat weight of 2 gsm to 80 gsm and the coating may have a dry coat weight of 80 gsm to 500 gsm. The coating may have a higher dry coat weight than the foundation layer. The foundation layer may comprise an acrylic resin, an alkyd resin, a polyurethane resin, a polysaccharide resin, a polyester resin, a polycarbonate resin, and / or mixtures thereof. The reinforcing material may comprise a woven fabric. The reinforcing material may comprise synthetic fibres. The body of fibres may comprise leather fibres. According to various, but not necessarily all, examples there is provided clothing, footwear, accessories or upholstery comprising a composite sheet material according to any of the preceding paragraphs. According to various, but not necessarily all, examples there is provided a method of forming a composite sheet material, wherein the method comprises: forming fibres into a web; locating an arrangement comprising the web and a reinforcing material into a hydroentanglement apparatus, wherein the web defines a second layer of the arrangement and the reinforcing material defines a first layer of the arrangement; subjecting the arrangement to successive hydroentanglement steps in the hydroentanglement apparatus, wherein subjecting the arrangement to successive hydroentanglement steps causes the fibres of the web to entangle with each other to form a body of fibres, and causes a mechanical bond to form between the body of fibres and the reinforcing material; applying a liquid mixture onto the body of fibres, the mixture comprising a resin, and allowing the mixture to cure or dry to form a foundation layer, wherein the resin of the foundation layer overlays the body of fibres and partially penetrates into the body of fibres; and applying a coating onto the foundation layer. The liquid mixture may have a solids percentage of 0.5% to 50%. The liquid mixture may have a solids percentage of 0.5% to 25%. The liquid mixture may have a solids percentage of 1% to 15%. The method may comprise subjecting the foundation layer to a smoothing treatment. The smoothing treatment may comprise buffing the foundation layer. The liquid mixture may have a viscosity of 1 to 500 cPs. The liquid mixture may be applied to the body of fibres by roller coating, gravure coating, gravure printing, spraying, or transfer coating. The liquid mixture may comprise a surfactant. The liquid mixture may be foamed prior to application to the body of fibres. The liquid mixture may be an aqueous mixture. The liquid mixture may comprise a filler. According to various, but not necessarily all, examples there is provided examples as claimed in the appended claims. While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all of the features described in respect of other examples of the disclosure, and vice versa. BRIEF DESCRIPTION Some examples will now be described with reference to the accompanying drawings in which: FIG. 1 shows a method of forming a composite sheet material according to examples of the disclosure; FIG. 2 shows a comparative example composite sheet material; FIG. 3 shows a first example composite material; FIG. 4 shows a second example composite material; FIG. 5 shows a plot of the amount of a foundation layer per unit area (gsm) versus average penetration of the foundation layer into a body of fibres (mm) at different solids content of a liquid mixture; FIG. 6 shows a plot of the amount of the foundation layer per unit area (gsm) versus poor break performance of the resulting material at different solids content of the liquid mixture; and FIG. 7 shows a plot of the average penetration of the foundation layer into the body of fibres (mm) versus poor break performance of the resulting material at different solids content of the liquid mixture. DETAILED DESCRIPTION In examples of the disclosure, a composite sheet material is provided. A method of forming the composite sheet material is also provided. The composite sheet material comprises a reinforcing material and a body of fibres. The body of fibres includes fibres interlocked with each other by entanglement. At least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material. The composite sheet material further comprises a foundation layer comprising a resin. The resin overlays the body of fibres and at least partially penetrates into the body of fibres. A coating overlays the foundation layer. The reinforcing material, the body of fibres, the foundation layer and the coating can be considered as first, second, third, and fourth layers respectively. The reinforcing material is in the form of a sheet. The reinforcing material could also be considered as a reinforcing structure or a first layer. The reinforcing material may comprise a structure defined by a fabric. The fabric could be a woven fabric, a knitted fabric, or a non-woven fabric. Alternatively, the reinforcing material may comprise a structure defined by a combination of a woven fabric, a knitted fabric, and / or a nonwoven fabric. The fabric of the reinforcing material is preferably a durable fabric. A durable fabric may be suitable for multiple cycles of use and washing, as opposed to a disposable fabric, which is not suitable for repeated use and / or washing cycles. A durable fabric is suitable for use in clothing, footwear, accessories and / or upholstery. A durable fabric may be tear resistant (for instance greater than 10 N tear strength as measured by BS EN ISO 3377-2 2016 using a double edged tear) and may have high tensile strength (for instance a tensile strength of greater than 7 N / mm as measured by tensile strength test BS EN ISO 3376-2002). The fabric of the reinforcing material could be a recycled fabric. In some examples, the reinforcing material has a different weight per unit area to the body of fibres, and preferably has a lower weight per unit area than the body of fibres. In other examples, the reinforcing material has the same weight per unit area as the body of fibres. The reinforcing material may have a weight per unit area of 40 gsm to 200 gsm. Preferably, the reinforcing material has a weight per unit area of 60 gsm to 100 gsm. The reinforcing material may comprise virgin fibres and / or recycled fibres. The reinforcing material may comprise natural, naturally derived and / or synthetic fibres. A non-exhaustive list of example natural fibres includes: wool, cotton, leaf, flax, bast and silk fibres. A non-exhaustive list of example naturally derived fibres includes: bamboo, viscose and soybean fibres. A non-exhaustive list of example synthetic fibres includes: polyester, nylon, polypropylene, polyamide, elastane, and acrylic fibres. In some examples, the reinforcing material comprises splittable fibres. The splittable fibres of the reinforcing material may be splittable bicomponent fibres. Splittable bicomponent fibres comprise at least two different fibres arranged in distinct segments across the cross-section of the splittable fibre. For example, the at least two different fibres may comprise polyester fibres and polyamide fibres, which may be microfibres. The body of fibres comprises fibres interlocked together by entanglement. The body of fibres forms a second layer of the composite sheet material. The body of fibres may be interlocked together by hydroentanglement by subjecting an arrangement comprising a web of fibres to high pressure jets of liquid to interlock the fibres together by entanglement. At least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material. At least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material through gaps in the reinforcing material. At least some of the fibres of the body of fibres may be mechanically bonded to the reinforcing material by being pushed by high-pressure jets of liquid into gaps in the reinforcing material. The body of fibres may comprise synthetic, natural fibres and / or naturally derived fibres. A non-exhaustive list of example natural fibres includes: wool, cotton, leaf, flax, bast and silk fibres. A non-exhaustive list of example naturally derived fibres includes leather, soybean, viscose and bamboo fibres. A non-exhaustive list of example synthetic fibres includes: polyester, nylon, polypropylene, polyamide, elastane, and acrylic fibres. The synthetic fibres may be bi-composite fibres. In some examples, the body of fibres may comprise synthetic and natural fibres in combination. The body of fibres may comprise splittable fibres, which may be naturally derived or synthetic. The fibres of the body of fibres may be in a non-woven arrangement. In some examples, the body of fibres has a weight per unit area of up to 750 gsm, up to 600 gsm, up to 550 gsm, up to 500 gsm, up to 400 gsm, or up to 300 gsm. In some examples, the body of fibres has a weight per unit area of at least 20 gsm, at least 50 gsm, at least 80 gsm, or at least 100 gsm. In some examples, the body of fibres has a weight per unit area of 50 gsm to 500 gsm. Preferably, the body of fibres has a weight per unit area of 100 gsm to 500 gsm. In examples, such as the illustrated examples of FIGS. 2 to 4 described below, the body of fibres comprises leather fibres. The leather fibres can have a non-woven arrangement. The leather fibres can be interlocked together by entanglement. The leather fibres can be interlocked together by hydroentanglement by subjecting an arrangement comprising a web of leather fibres to high pressure jets of liquid to interlock the fibres together by entanglement. The body of fibres in such examples may also comprise non-leather fibres and / or additives or other materials. The leather fibres may be derived from waste leather. For illustrative purposes only, the fibre length resulting from disintegrating of waste leather in textile reclaiming equipment ranges from less than 1 mm with occasional fibres up to 20 mm. The fibre structure of natural leather before disintegration consists of closely interwoven bundles of collagen fibres, which in turn consist of even finer fibrils, many of which become separated during the mechanical action. This results in a range of fibre diameters from about 100 microns for the bundles to very fine fibres below 1 micron for individual fibrils. The body of fibres may comprise fibres derived from textile waste. Textiles are materials formed by intertwining or interlocking fibres. Textiles include woven fabrics, knitted fabrics, and non-woven fabrics. A non-woven fabric is defined as any fabric other than a woven or knitted fabric, such as felt or a needle-punched structure. Animal hides such as leather are not considered as textiles or fabrics, as they are not fabricated by intertwining or interlocking fibres. Animal hide fibres are thus not considered as textile fibres. Thus, in this specification, the term “textile” means the same as “non-leather textile”. Textile waste includes post-agricultural textile waste (also known as pre-industrial textile waste), industrial textile waste, post-industrial textile waste, pre-consumer textile waste, and / or post-consumer textile waste. The textile waste described herein may comprise one or more than one of these waste material components. Fibres derived from textile waste can be prepared by shredding, granulating and milling the textile waste. Textile waste comprises textile fibres. Textile fibres are the primary raw materials used in textile manufacture. Textile fibres generally have a substantially uniform diameter throughout their length. In most, but not all, examples, textile fibres have a linear density of 1.5 - 3.3 dtex. Textile fibres include natural fibres, naturally derived fibres and / or synthetic fibres. Example natural fibres used in textile manufacture are wool, cotton, flax, bast and silk fibres. Example naturally derived fibres used in textile manufacture are bamboo, viscose and soybean fibres. Example synthetic fibres used in textile manufacture are polyester, nylon, polypropylene, polyamide, elastane, and acrylic fibres. Some, but not all, natural and naturally derived textile fibres, such as cotton, flax, bast or viscose, are cellulosic textile fibres. Cellulosic textile fibres comprise cellulose. Textile waste in many, but not all, examples includes more than one type of textile fibre. In other words, the textile waste is mixed or non-homogeneous. In some examples, the textile waste includes more than two types of textile fibres. Depending on the source, the textile waste can include several types of textile fibres in varying ratios. A different type of textile fibre is a fibre made from a different material. Example types of textile fibres include wool, cotton, viscose, flax, soybean, bamboo, silk, polyester, nylon, polypropylene, polyamide, elastane, acrylic, bast or modal fibres. The textile waste may include one or more, two or more, or three or more of these types of textile fibres. In some examples, the textile waste includes both i) synthetic fibres and ii) natural or naturally derived fibres. The textile waste may include 10 wt.% to 90 wt.% natural or naturally derived fibres and 10 wt.% to 90 wt.% synthetic fibres, such as 70 wt.% synthetic fibres and 30 wt.% natural or naturally derived fibres. Where the textile waste is derived from denim, the textile waste may include 50 wt.% to 98 wt.% cotton fibres and 2 wt.% to 50 wt.% synthetic fibres (e.g., polyester and / or elastane). Table 1 below shows example fibre types that could be used in the reinforcing material and the body of fibres of the composite sheet materials described herein. Table 1 includes example composite sheet materials A to N and specifies the fibre types that make up the body of fibres and the reinforcing material, along with any additive fibres included in the body of fibres. Table 1 Example Reinforcing material fibre type Body of fibres fibre type Additive fibre type in the body of fibres A Polyester Waste leather Bicomponent splittable B Recycled polyester Waste leather Bicomponent splittable C Polyamide Waste leather Bicomponent splittable D Cotton Waste leather Bicomponent splittable E Flax Waste leather - F Recycled polyamide Waste leather Bicomponent splittable G Polyester Bast Bicomponent splittable H Recycled polyester Bast Bicomponent splittable I Polyamide Bast - J Cotton Bast Polylactic acid splittable K Flax Bast - L Polyester Leaf Polyester M Recycled polyester Mixed postconsumer textile waste N Recycled polyester Mixed synthetic - In some examples, the composite sheet material includes a further body of fibres on the opposite side of the reinforcing material to the body of fibres. The further body of fibres may be substantially the same as the body of fibres. Where the composite sheet material includes a body of fibres on the opposite side of the reinforcing material to the 10 body of fibres, the body of fibres and further body of fibres may each have a weight per unit area of from 50 gsm to 750 gsm. In some examples, the body of fibres is different from the further body of fibres. For instance, the body of fibres may have a weight per unit area of up to 500 gsm and the further body of fibres may have a weight per unit area of up to 200 gsm. The body of fibres may have a weight per unit area of 200 gsm to 600 gsm, and the further body of fibres may have a weight per unit area of 100 gsm to 250 gsm. The composite sheet material further comprises a foundation layer comprising a resin. The foundation layer could also be referred to as a correction layer. The foundation layer can be considered as a third layer of the composite sheet material. The foundation layer is an intermediate layer between the body of fibres and the coating. The resin of the foundation layer overlays the body of fibres and at least partially penetrates into the body of fibres. In other words, a first portion of the foundation layer occupies interstitial spaces between fibres of the body of fibres and a second portion of the foundation layer overlays the external surface of the body of fibres. In some examples, the resin of the foundation layer penetrates on average up to 600 microns into the body of fibres, i.e., the first portion has an average depth of up to 600 microns. The average penetration can be determined using optical microscopy, by calculating a mean depth from a number of optical microscopy measurements. The optical microscopy may for instance be carried out at approximately 50x magnification using a Leica ® M205C Microscope. In some examples, the resin of the foundation layer penetrates on average up to 100 microns, up to 200 microns, up to 300 microns, up to 400 microns, up to 500 microns, up to 600 microns, or up to 1 mm into the body of fibres. In some examples, the resin of the foundation layer penetrates on average at least 100 microns, at least 200 microns, or at least 250 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 100 microns to 500 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 200 microns to 400 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 250 microns to 500 microns into the body of fibres. In some examples, the foundation layer has a dry coat weight of up to 200 gsm, up to 120 gsm, or up to 80 gsm. In some examples, the foundation layer has a dry coat weight of at least 2 gsm, at least 20 gsm, at least 30 gsm, or at least 50 gsm. Preferably, the foundation layer has a dry coat weight of 1 gsm to 90 gsm, 2 gsm to 80 gsm, 5 gsm to 60 gsm, 20 gsm to 50 gsm, or 20 to 40 gsm. In some examples, the foundation layer has an average thickness of up to 1 mm, up to 700 microns, up to 500 microns, up to 300 microns, or up to 100 microns. Preferably, the foundation layer has an average thickness of 100 microns to 500 microns. The average thickness of a layer can be determined using optical microscopy, by calculating a mean thickness from a number of optical microscopy measurements. The optical microscopy may for instance be carried out at approximately 50x magnification using a Leica ® M205C Microscope. In some examples, the foundation layer predominantly comprises the resin. Substantially all of the foundation layer may be made of the resin. The resin may, for example, comprise an acrylic resin, an alkyd resin, a polyester resin, a polycarbonate resin, a polyurethane resin, a polysaccharide resin, and / or mixtures thereof. A coating overlays the foundation layer. The coating may be for decoration and / or protection of the composite sheet material. The coating can be considered as a fourth layer of the composite sheet material. The coating may be a polymeric coating. For instance, the coating may have an average thickness of at least 100 microns, at least 150 microns, at least 200 microns or at least 250 microns. The coating may have a higher dry coat weight than the foundation layer. The coating may have a dry coat weight of at least 80 gsm, or at least 150 gsm. In some examples, the coating has a dry coat weight of 80 gsm to 500 gsm. Preferably, the coating has a dry coat weight of 80 gsm to 200 gsm. In some examples, the coating includes a plurality of recesses to simulate leather grain. In some examples, the coating may include a number of component sublayers. For instance, the coating may include an adhesive sublayer along with a protective sublayer and / or a decorative sublayer. The composite sheet material may have an average thickness of 0.5 mm to 2.5 mm. Preferably, the composite sheet material has an average thickness of 0.7 mm to 1.6 mm, such as 1.2 mm. The composite sheet material may have a weight per unit area of over 250 gsm. Preferably, the composite sheet material has a weight per unit area of 350 gsm to 600 gsm, such as 450 gsm. It is to be appreciated that the thickness and weight per unit area of the composite sheet material and the layers that make up the composite sheet material can vary depending on the application. The composite sheet material can be formed using the following method. As shown in FIG. 1, the method 100 of forming a composite sheet material comprises the step 110 of forming fibres into a web. The fibres may comprise synthetic, natural fibres and / or naturally derived fibres. A non-exhaustive list of example natural fibres includes: wool, cotton, leaf, flax, bast and silk fibres. A non-exhaustive list of example naturally derived fibres includes: leather, soybean, viscose and bamboo fibres. A non-exhaustive list of example synthetic fibres includes: polyester, nylon, polypropylene, polyamide, elastane, and acrylic fibres. The synthetic fibres may be bi-composite fibres. In some examples, the fibres may comprise synthetic and natural fibres in combination. The fibres may comprise splittable fibres, which may be naturally derived or synthetic. The fibres may comprise fibres derived from textile waste. In examples wherein the web comprises leather fibres, the leather fibres may be derived from waste leather. For illustrative purposes only, the fibre length resulting from disintegrating of waste leather in textile reclaiming equipment ranges from less than 1 mm with occasional fibres up to 20 mm. The fibre structure of natural leather before disintegration consists of closely interwoven bundles of collagen fibres, which in turn consist of even finer fibrils, many of which become separated during the mechanical action. This results in a range of fibre diameters from about 100 microns for the bundles to very fine fibres below 1 micron for individual fibrils. The web may be in the form of a sheet. The web may be a non-woven web, and can be formed by airlaying. In some examples, the web is needle punched once formed. Prior to (i.e., upstream of) forming the fibres into the web, the fibres for forming the web may be opened from a bale and / or a silo using a fibre opener. In some examples, the fibres comprise bicomponent fibres, such as polylactic acid / polylactic acid bicomponent fibres, where each polylactic acid element has a different melting point, or polyethylene / polypropylene bicomponent fibres. The web of fibres may comprise 1 wt.% to 10 wt.% of the bicomponent fibres. Preferably, the web comprises 2 wt.% to 5 wt.% of the bicomponent fibres. Where the fibres are formed into a web using airlaying, the blending of the non-bicomponent fibres with the bicomponent fibres may be carried out by agitators in airlay forming heads. In examples where the fibres are formed into a web using airlaying, the fibres may be airlaid onto a support material. The support material is preferably a tissue material. The tissue material may have a weight per unit area (i.e. grammage) of 10 to 25 gsm, such as 18 gsm. In some examples, the web has a weight per unit area of up to 750 gsm, up to 600 gsm, up to 550 gsm, up to 500 gsm, up to 400 gsm, or up to 300 gsm. In some examples, the web has a weight per unit area of at least 20 gsm, at least 50 gsm, at least 80 gsm, or at least 100 gsm. In some examples, the web has a weight per unit area of 50 gsm to 500 gsm. Preferably, the web has a weight per unit area of 100 gsm to 500 gsm. In examples where the web comprises bicomponent fibres, the formed web may be inserted into and heated in an oven to cause partial melting of the bicomponent fibres. In some examples, the formed web is heated to 140 °C to 170 °C in the oven. The formed web may be heated in the oven for 20 seconds to 110 seconds. The heating of the web including synthetic bicomponent fibres has been found to stabilise the web. The stabilisation of the web enables the web to be processed more readily. Otherwise, the web is more likely to fall apart during processing, for example during winding of the web into a roll, during the formation of the web in an airlaying process, and / or during unwinding of the web roll prior to hydroentanglement. Following the formation of the web, the web may be formed into a roll. The method 100 further comprises locating an arrangement comprising the web and a reinforcing material into a hydroentanglement apparatus, as illustrated by the numeral 120 in FIG. 1. The arrangement may be in the form of a sheet, and can be formed on a support by laying a sheet of the web onto a sheet of the reinforcing material. The web defines a second layer of the arrangement, and the reinforcing material defines a first layer of the arrangement. The reinforcing material is in the form of a sheet. The reinforcing material could also be considered as a reinforcing structure. The reinforcing material may comprise a structure defined by a fabric. The fabric could be a woven fabric, a knitted fabric, or a non-woven fabric. Alternatively, the reinforcing material may comprise a structure defined by a combination of a woven fabric, a knitted fabric, and / or a non-woven fabric. The fabric of the reinforcing material is preferably a durable fabric. A durable fabric may be suitable for multiple cycles of use and washing, as opposed to a disposable fabric, which is not suitable for repeated use and / or washing cycles. A durable fabric is suitable for use in clothing, footwear, accessories and / or upholstery. A durable fabric may be tear resistant (for instance greater than 10 N tear strength as measured by BS EN ISO 3377-2 2016 using a double edged tear) and may have high tensile strength (for instance a tensile strength of greater than 7 N / mm as measured by tensile strength test BS EN ISO 3376-2002). The fabric of the reinforcing material could be a recycled fabric. In some examples, the reinforcing material has a different weight per unit area to the web, and preferably has a lower weight per unit area than the web. In other examples, the reinforcing material has the same weight per unit area as the web. The reinforcing material may have a weight per unit area of 40 gsm to 200 gsm. Preferably, the reinforcing material has a weight per unit area of 60 gsm to 100 gsm. The reinforcing material may comprise virgin fibres and / or recycled fibres. The reinforcing material may comprise natural, naturally derived and / or synthetic fibres. In some examples, the reinforcing material comprises splittable fibres. The splittable fibres of the reinforcing material may be splittable bicomponent fibres. Splittable bicomponent fibres comprise at least two different fibres arranged in distinct segments across the cross-section of the splittable fibre. For example, the at least two different fibres may comprise polyester fibres and polyamide fibres, which may be microfibres. In some examples, the arrangement includes a further web on the opposite side of the reinforcing material to the web. The further web may be substantially the same as the web described above. Alternatively, the further web may have different weight per unit area to the web, a different structure to the web, and / or have a different composition to the web. The method 100 further comprises subjecting the arrangement to successive hydroentanglement steps in the hydroentanglement apparatus, as illustrated by the numeral 130 in FIG. 1. The hydroentanglement steps include exposing the arrangement to high pressure jets of liquid over a surface of the arrangement. In some examples, the liquid is water. The jets may be directed firstly onto a first face of the arrangement, and subsequently onto a second opposite face of the arrangement. The jet pressure applied to the surface of the arrangement may be 180 bar to 380 bar. Subjecting the arrangement to successive hydroentanglement steps causes the fibres of the web to entangle with each other. Accordingly, the fibres of the web interlock with each other by entanglement. Subjecting the arrangement to successive hydroentanglement steps also causes a mechanical bond to form between the fibres of the web and the reinforcing material. This bond is caused by some of the fibres of the web being pushed by the high-pressure jets of liquid into gaps in the reinforcing material. In some examples, in the hydroentanglement apparatus the arrangement is supported on a porous conveyor, which may be the support on which the arrangement is formed, and advanced through one or more treatment stations. In other examples, in the hydroentanglement apparatus the arrangement is supported on a porous drum, which may be the support on which the arrangement is formed, and advanced through one or more treatment stations. The one or more treatment stations comprise liquid outlets for subjecting the arrangement to high pressure jets of such liquid. Each of the successive hydroentanglement steps on one or each face of the arrangement may be carried out at a different treatment station in the apparatus. In such examples, the conveyor or the drum is arranged to support and advance the arrangement through each of the respective treatment stations. Following hydroentanglement, the formed composite sheet material may then be dried, for instance by heating the composite sheet material in an oven. Following hydroentanglement, no adhesive is necessary to structurally bond the fibres. Thus, the composite sheet material may be substantially without any adhesive bonding of the fibres, the mechanical interlocking of the fibres caused by hydroentanglement being the predominant means of attaining and maintaining the integrity of the structure. The reinforcing material forms an intrinsic part of the material (e.g., as opposed to being a backing layer). For example, it may be that the reinforcing material and the body of fibres cannot be separated from each other without the use of one or more tools. In some examples, following hydroentanglement, the body of fibres may be impregnated with an additive. For instance, a softening agent may be applied to the body of fibres. Following hydroentanglement, the method 100 comprises applying a liquid mixture onto the body of fibres, as illustrated by the numeral 140 in FIG. 1. The mixture comprises a resin. The liquid mixture overlays the outer surface of the body of fibres. The liquid mixture can also at least partially penetrate into the body of fibres, for instance by flowing into holes or gaps in the outer surface of the body of fibres. The liquid mixture may be water-based, i.e., an aqueous mixture. The resin of the liquid mixture could be a resin solution, dispersion, emulsion or a curable resin. The resin dispersion includes polymers dissolved, dispersed or suspended in a liquid medium. A curable resin includes a polymer precursor that forms a solid polymer in response to a specific stimulus. The stimulus could be for instance heat, light, moisture, a hardener and / or a catalyst. Preferably, the liquid mixture comprises a resin dispersion. The resin dispersion may be a polyurethane dispersion, an acrylic dispersion, an alkyd dispersion, a polyester dispersion, a polycarbonate dispersion, a polysaccharide dispersion, and / or mixtures thereof. The solids percentage of the liquid mixture may be modified to affect the viscosity of the liquid mixture. In some examples, the liquid mixture has a solids percentage of 0.5% to 50% by weight or 0.5% to 25% by weight. Preferably, the liquid mixture has a solids percentage of 1% to 15% by weight, or 2% to 14% by weight, or 5 to 15% by weight. Most preferably, the liquid mixture has a solids percentage of 7% to 13% by weight. A less viscous mixture may penetrate further into the body of fibres. In some examples, the liquid mixture has a viscosity of 1 to 500 cPs at 25 °C. The liquid mixture could be applied onto the body of fibres using a variety of methods. For instance, the liquid mixture could be applied to the body of fibres by roller coating, gravure coating, gravure printing, spraying, or transfer coating. Example liquid mixtures are shown in Tables 2 and 3 below. Materials Used Polymer or polymer precursor Rolflex ® Bio 45 - Waterborne polyurethane (30wt.% Solids), Lamberti Permutex ® RU4049 - Waterborne polyurethane (40wt.% Solids), Stahl Esacol ® ED5 - Polysaccharide powder, Lamberti Methocel ® A4C - Methylcellulose polymer, DuPont Fillers Omyasphere ® 200 - Closed-cell expanded perlite, Omya Spheromera acrylic beads - Acrylic beads, Lamberti Expancel ® 461 WE - Thermoplastic microspheres, Nouryon Surfactants Prifac ® 8944 - Rapeseed fatty acid, Croda BYK®-333 - Silicone based surfactant, BYK Exotaine CAPB 30 - Cocamidopropyl betaine, EOC Group Crosslinkers Crosslinker 08 - isocyanate crosslinker, Lamberti Permutex ©XR5577 - carbodiimide crosslinker, Stahl Table 2 Component Example Component Example (wt.%) 1 2 3 4 5 6 7 8 9 10 Carrier Water 57 66 76 65 65 57 63 63 63 61 Resin Rolflex ® Bio 45 43 34 24 34 34 - 32 32 32 34 Resin Permutex ® RU4049 - - - - - 43 - - - - Surfactant BYK®-333 - - - 1 - - - - - - Surfactant Prifac ® 8944 - - - - 1 - - - - - Filler Omyasphe -re ® 200 - - - - - - 5 - - - Filler Spheromer -a acrylic beads - - - - - - - 5 - - Filler Expancel ® 461 WE - - - - - - - - 5 - Crosslinker Crosslinker 08 - - - - - - - - - 5 Table 3 Component Example Component Example (wt.%) 11 12 13 14 15 Carrier Water 97.5 96.5 97.5 93.75 93.75 Resin Esacol ® ED5 2.5 2.5 1.25 1.25 1.25 Resin Methocel ® A4C - - 1.25 - - Surfactant Exotaine CAPB 30 - 1.0 - - - Crosslinker Permutex ® XR5577 - - - 5 - Crosslinker Crosslinker 08 - - - - 5 The examples liquid mixtures shown in Tables 2 and 3 comprise waterborne resin(s), i.e., water is used as a carrier medium for the resin(s). The liquid mixture may comprise a crosslinker, such as an isocyanate crosslinker or a carbodiimide crosslinker. In some examples, the liquid mixture comprises a surfactant. The surfactant may improve the dispersion of the resin and / or influence the flow of the mixture over the body of fibres. In some examples, the liquid mixture comprises a filler. The filler may comprise calcium carbonate, clay, glass beads, ceramic beads and / or plastic beads. In some examples, the liquid mixture is foamed prior to application onto the body of fibres. The liquid mixture may include a foaming agent, such as azodicarbonamide, hydrazide, sodium bicarbonate, or zinc bicarbonate. Once the liquid mixture has been applied onto the body of fibres, the resin overlays the body of fibres and at least partially penetrates into the body of fibres. The mixture is then allowed to cure or dry to form a foundation layer. The resin of the foundation layer overlays the body of fibres and at least partially penetrates into the body of fibres. In other words, a first portion of the foundation layer occupies interstitial spaces between fibres of the body of fibres and a second portion of the foundation layer overlays the external surface of the body of fibres. In some examples, the resin of the foundation layer penetrates on average up to 600 microns into the body of fibres, i.e., the first portion has an average depth of up to 600 microns. In some examples, the resin of the foundation layer penetrates on average up to 100 microns, up to 200 microns, up to 300 microns, up to 400 microns, up to 500 microns, up to 600 microns, or up to 1 mm into the body of fibres. In some examples, the resin of the foundation layer penetrates on average at least 100 microns, at least 200 microns, or at least 250 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 100 microns to 500 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 200 microns to 400 microns into the body of fibres. The resin of the foundation layer may penetrate on average from 250 microns to 500 microns into the body of fibres. In some examples, the foundation layer may be subject to smoothing treatments. The smoothing treatments can produce a more even surface that is more suitable for coating. Typical smoothing treatments include buffing, applying a heated roller and / or applying a plate press to the foundation layer. The method 100 further comprises applying a coating to the foundation layer, which is illustrated by the numeral 150 of FIG 1. The coating may be a polymeric coating, and may be a polyurethane or PVC coating. The coating may be water-based. In some examples, the coating may be applied onto the foundation layer in a free-flowing liquid form, for instance by roller coating, gravure coating, gravure printing, or spraying. The coating may be polymeric, and may be allowed to dry or cure on the foundation layer once applied. Prior to application, the polymeric coating in liquid form may be a solventless, solvent-based, or water-based dispersion or solution. In other examples, the coating may be applied onto the foundation layer in the form of a viscous liquid or in a solid form. For instance, a polymeric coating may be applied onto the foundation layer using transfer coating. To apply a transfer coating, a polymeric material can be applied to release paper, and dried or cured prior to being bonded to the material / construction. The coating applied to the release paper may be brought into contact with the foundation layer to transfer the coating from the release paper and onto the foundation layer. The release paper can then be removed from the coating to leave the coating bonded to the foundation layer. The coating may have an average thickness of at least 100 microns, at least 150 microns, at least 200 microns or at least 250 microns. The coating may have a higher dry coat weight than the foundation layer. The coating may have a dry coat weight of at least 80 gsm, or at least 150 gsm. The coating may have a higher dry coat weight than the foundation layer. In some examples, the coating has a dry coat weight of 80 gsm to 500 gsm. Preferably, the coating has a dry coat weight of 80 gsm to 200 gsm. In some examples, the coating includes a plurality of recesses to simulate leather grain. In some examples, a topcoat is applied to the coating. The topcoat may overlie the coating. The topcoat may be a haptic modifier layer. The topcoat may be used as a haptic modifier layer. The topcoat can provide additional durability, abrasion, scratch resistance, UV protection, or other surface property such as stain resistance, water repellency, hydrophobicity, or control of gloss. FIGS. 3 and 4 illustrate example composite sheet materials according to the disclosure, and FIG. 2 illustrates a comparative example composite sheet material without a foundation layer. The sheet materials in FIGS. 2, 3 &4 have been folded over to illustrate the effects of folding on the coating. The composite sheet material of FIG. 3 includes a reinforcing material, a body of fibres, a further body of fibres on the opposite side of the reinforcing material to the body of fibres, a foundation layer formed from the example liquid mixture 1 of Table 2, and a polyurethane coating. The body of fibres and further body of fibres are each a blend of leather fibres with synthetic bicomponent fibre additives, and the reinforcing material is a woven fabric made from polyester fibres. The composite sheet material of FIG. 4 includes a reinforcing material, a body of fibres, a further body of fibres on the opposite side of the reinforcing material to the body of fibres, a foundation layer formed from the example liquid mixture 11 of Table 3, and a coating. The body of fibres and further body of fibres are each a blend of leather fibres with synthetic bicomponent fibre additives, and the reinforcing material is a woven fabric made from polyester fibres. The coating is a polyurethane coating. The composite sheet material of FIG. 2 is the same as the examples of FIGS. 3 and 4, but does not include a foundation layer. As demonstrated clearly in FIGS. 3 and 4, the foundation layer significantly reduces the wrinkling and folding of the coating, thereby providing a smoother and more uniform surface in use. Table 4 below shows the “poor break” performance of composite sheet materials with different foundation layer compositions, and an example with no foundation layer. The examples of Table 4 are similar to those of FIGS. 3&4, but a different foundation layer composition is used and the reinforcing material is a woven fabric made from polyamide fibres. An uneven surface or weak adhesion of the coating to the substrate can increase the probability of poor break, which results in wrinkles, cracks or creases in the surface of a coating. The incidence of poor break is measured using the standard assessment SATRA TM36. A lower value for poor break represents improved performance. Table 4 Foundation Layer composition Poor break score No Foundation Layer 4 Formed from mixture 14 of Table 3 2 Formed from mixture 10 of Table 2 3.5 Formed from mixture 15 of Table 3 3.5 As shown in Table 4, the presence of a foundation layer improves the poor break performance of the composite sheet materials. Of the examples of Table 4, the foundation layer formed from mixture 14 of Table 3 provides the greatest improvement in poor break performance 4. The example composite sheet materials of Table 5 below are similar to those of Table 4, but include different foundation layer compositions. The foundation layers of the example composite sheet materials 100 to 104 of Table 5 below have differing weights per unit area and penetrate into the body of fibres to different depths on average. The liquid mixtures used to form the foundation layers of examples 100 to 104 of Table 5 each comprise the same type of polyurethane resin, but the polyurethane resin is present in the liquid mixture at varying solids percentages. In examples 100 to 104 of Table 5, the polyurethane resin is Rolflex® Bio 45, as used in for instance examples 1 to 3 of Table 2. An example composite sheet material 105 with no foundation layer is also included in Table 5. Table 5 shows the peel strength, “Bally flex” performance, and “poor break” performance of composite sheet materials. The incidence of poor break is measured using the standard assessment SATRA TM36. Bally flex is measured using the standard assessment SATRA TM55. Bally flex represents the resistance of a material to cracking or other types of failure at flexing creases after a number of flexing cycles. FIGS. 5, 6, and 7 illustrate some of the values from Table 5 plotted onto graphs. Table 5 Example Solids content of liquid mixture (wt.%) Dry foundation layer weight (gsm) Average penetration into body of fibres (mm) Peel strength (N / cm) Bally flex test at 100,000 flexing cycles Poor Break 100 13% 21 0.28 13.0 Pass 4.5 101 13% 82 0.57 12.7 Fail 3.5 102 10% 35 0.39 11.4 Fail 3.5 103 10% 27 0.31 13.7 Pass 4 104 7% 23 0.39 15.1 Marginal Fail 4.5 105 None 0 N / A 13.3 Fail 5.5 When the weight per unit area of the foundation layer is relatively low (for instance a dry weight of below 40 gsm), the flex performance can alter from a pass to a fail depending upon penetration depth. The penetration depth is dependent upon the solids percentage of the liquid mixture for forming the foundation layer. Poor break performance improves with increasing penetration depth and weight per unit area of the foundation layer, though this performance plateaus as the penetration depth and weight per unit area are increased further. The poor break score can be improved at a higher weight per unit area of the foundation layer, but this can be at the detriment of flex performance. There is thus described a composite sheet material and a method of forming a composite sheet material with a number of advantages as described above and below. The composite sheet material is strong and durable. The composite sheet material can also incorporate waste fibres, providing an environmental benefit. The mechanically bonded structure of bodies of fibres subjected to hydroentanglement is irregular, and the surface of the sheet material may include “jet lines” formed by the action of the high pressure jets of liquid. An uneven surface can increase the probability of poor break, which results in wrinkles, cracks or creases in the surface of a coating. It has been found that the examples with a foundation layer, such as those shown in FIGS. 3 and 4, have reduced incidence of “poor break” when compared to the example of FIG. 2. The composite sheet material described herein provides a smooth and uniform surface. This uniform surface reduces the incidence of poor break, improves appearance, allows for more efficient processing / buffing of the material, and improves durability. Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example, one, some or all of the layers may comprise additives. Different resins may be used. Different fibre types may be used. In some alternative examples, the liquid mixture described herein may be applied to the reinforcing layer instead of the body of fibres. In such examples, the resin of the foundation layer may overlay the reinforcing layer rather than the body of fibres. The coating may be applied to the foundation layer as described in previous examples. In these alternative examples there is provided a composite sheet material comprising: a reinforcing material; a body of fibres, the body of fibres including fibres interlocked with each other by entanglement, and wherein at least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material; a foundation layer comprising a resin, wherein the resin overlays the reinforcing layer; and a coating overlaying the foundation layer. The reinforcing layer, the body of fibres, the reinforcing layer may be as described in any of the previously described examples, though with a different ordering of layers, in which the body of fibres is adjacent to the reinforcing layer, the reinforcing layer is between the body of fibres and the foundation layer, the foundation layer is between the reinforcing layer and the coating, and the coating is adjacent to the foundation layer. In some of these alternative examples, the resin of the foundation layer may at least partially penetrate into the body of fibres through the reinforcing layer. For instance, in examples where the reinforcing layer comprises a woven fabric, the resin of the foundation layer may penetrate through the interstices of the woven fabric and at least partially penetrate into the body of fibres. The term ‘comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use ‘comprise’ with an exclusive meaning then it will be made clear in the context by referring to “comprising only one...” or by using “consisting”. In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ‘example’ or ‘for example’ or ‘can’ or ‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus ‘example’, ‘for example’, ‘can’ or ‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that a feature described with reference to one example but not with reference to another example, can where possible be used in that other example as part of a working combination but does not necessarily have to be used in that other example. Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims. Features described in the preceding description may be used in combinations other than the combinations explicitly described above. Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not. The term ‘a’, ‘an’ or ‘the’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a / an / the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use ‘a’, ‘an’ or ‘the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of ‘at least one’ or ‘one or more’ may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning. The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result. In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described. The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description. Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure. Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that the applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not emphasis has been placed thereon.

Claims

1. A composite sheet material comprising:a reinforcing material;a body of fibres, the body of fibres including fibres interlocked with each other by entanglement, and wherein at least some of the fibres of the body of fibres are mechanically bonded to the reinforcing material;a foundation layer comprising a resin, wherein the resin overlays the body of fibres and partially penetrates into the body of fibres; anda coating overlaying the foundation layer.

2. A composite sheet material according to claim 1, wherein the foundation layer has a dry coat weight of up to 200 gsm.

3. A composite sheet material according to claim 2, wherein the foundation layer has a dry coat weight of up to 120 gsm.

4. A composite sheet material according to any of the preceding claims, wherein the resin of the foundation layer penetrates on average up to 500 microns into the body of fibres.

5. A composite sheet material according to claim 4, wherein the resin of the foundation layer penetrates on average 250 microns to 500 microns into the body of fibres.

6. A composite sheet material according to any of the preceding claims, wherein the foundation layer has an average thickness of 100 microns to 500 microns.

7. A composite sheet material according to claim 1, wherein the foundation layer has a dry coat weight of up to 120 gsm and the coating has a dry coat weight of at least 150 gsm.

8. A composite sheet material according to claim 1, wherein the foundation layer has a dry coat weight of 2 gsm to 80 gsm and the coating has a dry coat weight of 80 gsm to 500 gsm.

9. A composite sheet material according to any of the preceding claims, wherein the coating has a higher dry coat weight than the foundation layer.

10. A composite sheet material according to any of the preceding claims, wherein the foundation layer comprises an acrylic resin, an alkyd resin, a polyurethane resin, a polyester resin, a polycarbonate resin, a polysaccharide resin, and / or mixtures thereof.

11. A composite sheet material according to any of the preceding claims, wherein the reinforcing material comprises a woven fabric.

12. A composite sheet material according to any of the preceding claims, wherein the reinforcing material comprises synthetic fibres.

13. A composite sheet material according to any of the preceding claims, wherein the body of fibres comprises leather fibres.

14. Clothing, footwear, accessories or upholstery comprising a sheet material according to any of the preceding claims.

15. A method of forming a composite sheet material, wherein the method comprises:forming fibres into a web;locating an arrangement comprising the web and a reinforcing material into a hydroentanglement apparatus, wherein the web defines a second layer of the arrangement and the reinforcing material defines a first layer of the arrangement;subjecting the arrangement to successive hydroentanglement steps in the hydroentanglement apparatus, wherein subjecting the arrangement to successive hydroentanglement steps causes the fibres of the web to entangle with each other to form a body of fibres, and causes a mechanical bond to form between the body of fibres and the reinforcing material;applying a liquid mixture onto the body of fibres, the mixture comprising a resin, and allowing the mixture to cure or dry to form a foundation layer, wherein the resin of the foundation layer overlays the body of fibres and partially penetrates into the body of fibres; andapplying a coating onto the foundation layer.

16. A method according to claim 15, wherein the liquid mixture has a solids percentage of 0.5% to 25%.

17. A method according to claim 16, wherein the liquid mixture has a solids percentage of 1% to 15%.

18. A method according to any of claims 15 to 17, wherein the method comprises subjecting the foundation layer to a smoothing treatment.

19. A method according to claim 18, wherein the smoothing treatment comprises buffing the foundation layer.

20. A method according to any of claims 15 to 19, wherein the liquid mixture has a viscosity of 1 to 500 cPs.

21. A method according to any of claims 15 to 20, wherein the liquid mixture is applied to the body of fibres by roller coating, gravure coating, gravure printing, spraying, or transfer coating.

22. A method according to any of claims 15 to 21, wherein the liquid mixture comprises a surfactant.

23. A method according to any of claims 15 to 22, wherein the liquid mixture is foamed prior to application to the body of fibres.

24. A method according to any of claims 15 to 23, wherein the liquid mixture is an aqueous mixture.

25. A method according to any of claims 15 to 24, wherein the liquid mixture comprises a filler.

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