Shapeable fabric

Abstract

Herein is described a shapeable fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

Description

[0001] Shapeable fabric

[0002] Field of the Invention

[0003] The present invention relates to shapeable fabrics comprising glass fibers, in particular shapeable fabrics to reinforce structural components such as wind turbine components. The present invention also relates to a process of producing a shapeable fabric. The present invention further relates to a fabric stack comprising a shapeable fabric, a shaped component comprising a fabric stack, and a process for producing a shaped component.

[0004] Background

[0005] It is known to use glass fibers to form reinforcement fabrics to reinforce structural components such as wind turbine blades or related components (e.g., spar caps).

[0006] Structural components containing reinforcement fabrics (reinforced structural components) are often formed by stacking layers of reinforcement fabrics in a mold, filling the mold with a resin, and curing the resin to form the component. This process can be time consuming.

[0007] Wind power and the use of wind turbines have gained increased attention as the quest for alternative energy sources continues. With increasing interests in generating more energy from wind power, technological advances in the art have allowed for increased sizes of wind turbines blades. Increasing the size of wind turbine blades also increases the time required to produce the wind turbine blades. An increase in the size of wind turbine blades also increases any problems associated with infusing reinforcement fabrics used to form the wind turbine blades with resin.

[0008] It would be desirable to provide improvements in efficiency of the production of reinforced structural components such as wind turbine blades.

[0009] Summary of the Invention

[0010] At its most general, the present invention provides a shapeable fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric.

[0011] In a first aspect, the present invention provides a shapeable fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

[0012] In a second aspect, the present invention provides a fabric stack comprising a plurality of layers of a shapeable fabric described herein.

[0013] In a third aspect, the present invention provides a shaped component comprising a fabric stack described herein.

[0014] In a fourth aspect, the present invention provides a process for producing a shapeable fabric, the process comprising: providing a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; providing a functionalised fiber layer on the reinforcing fiber layer, the functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and stitching the reinforcing fiber layer and functionalised fiber layer together using a stitching yarn to form the shapeable fabric.

[0015] In a fifth aspect, the present invention provides a process for producing a shaped component, the process comprising: stacking a plurality of layers of a shapeable fabric as described herein to provide a fabric stack; shaping the fabric stack; and heating the fabric stack at a temperature up to about 180 °C.

[0016] The present inventors have found that the present invention provides a shapeable fabric which provides improvements in the efficiency of the production of reinforced structure components such as wind turbine blades and related components. This is because these shapeable fabrics can be stacked and shaped (i.e., pre-shaped) before being incorporated into a reinforced structural component. The provision of the shapeable fabrics described herein is expected to increase the speed at which a reinforced structural component, e.g., a wind turbine blade, can be produced.

[0017] Overall, the shapeable fabrics described herein can lead to an increase in productivity and a reduction in non-conformance during lay up of fabrics in the production of structural components. There have been attempts to produce a shapeable fabric that has both good mechanical properties and good infusion properties so that the shapeable fabric may be used in the production of wind turbine blades. However, incorporating shapeable properties into fabrics useful in the production of structural components, such as in wind turbine blades, and the fabric still exhibiting good infusion properties, good mechanical properties (including mechanical properties of a composite material formed from the shapeable fabric) and good drapeability has proven difficult. The present inventors believe that the shapeable fabrics described herein exhibit good infusion properties along with good mechanical properties and good drapeability.

[0018] The functionalised fiber layer of the shapeable fabrics described herein, comprise (may be formed of) polymer fibers as described herein (for example, continuous or chopped polymer fibers as described herein, the polymer fibers may be described has polymer monofilaments, individual polymer fibers or polymer fiber strands) having a melting point of less than about 150 °C. The present inventors have found that by providing a shapeable fabric comprising a functionalised fiber layer as described herein, the mechanical properties (for example, stiffness) of the shapeable fabric provides a shapeable fabric can be changed by exposing the shapeable fabric to a temperature of about the melting point of the polymer fibers or greater such than the polymer fibers are at least partially melted or fully melted to form a functionalised fiber layer comprising partially molten or molten polymer fibers. After a shapeable fabric described herein is heated such that the polymer fibers are partially or fully melted, the shapeable fabric may then be cooled to provide a shaped fabric having different mechanical properties (for example, increased stiffness) compared to the shapeable fabric from which it was formed (the fabric before heating / thermal activation). For example, the shapeable fabric may be described as a drapeable shapeable fabric, while the shaped fabric (formed by thermally activating the shapeable fabric) exhibits increased stiffness compared to the shapeable fabric. The shaped fabric may be described as a semi-rigid fabric, for example a shaped fabric formed by partially melting the polymer fibers of the functionalised fiber layer. The present inventors have found that the increased stiffness of the shaped fabric improves handleability during lay-up of a composite article as well as good resistance to unravelling of the fabric.

[0019] The present inventors have found that the provision of a shapeable fabric as described herein with a functionalised fiber layer as described herein allows for mechanical properties of the fabric (e.g. stiffness and / or rigidity) to be changed on exposure to temperature (e.g. on thermal activation). The present inventors have found that by providing a shapeable fabric comprising a functional fiber layer as described herein, the shapeable fabric before thermal activation (i.e., before exposure to heat in order to partially or fully melt the polymer fibers of the functionalised fiber layer) exhibits improved drapeability compared to previous shapeable fabrics. The present inventors have also found that on thermal activation (i.e., exposing the shapeable fabric to heat in order to partially or fully melt the polymer fibers of the functionalised fiber layer), the polymer fibers of the functionalised fiber layer are at least partially melted to form a functionalised fiber layer comprising molten polymer fibers, and that subsequent cooling forms a shaped fabric comprising a functionalised fiber layer comprising fused polymer fibers which changes the mechanical properties of the fabric and allows for, for example, improved drapeability of the shapeable fabric to be combined with increased stiffness of the shaped fabric.

[0020] The shaped fabric may be described as comprising a functionalised fiber layer in which the polymer fibers are fused together. The shaped fabric may be described as comprising a functionalised fiber layer in which the polymer fibers are fused together, and polymer fibers are fused to at least one reinforcing layer of the shaped fabric.

[0021] Furthermore, the present inventors consider that providing a shapeable fabric as described provides improvements in drapeability and reduced fabric stiffness compared to previous attempts to provide a shapeable fabric, at least partly due to the provision of the polymer fibers of the functionalised layer as described herein (the polymer fibers may be referred to as independent polymer fibers) which appears to improve handleability and drapability of the fabrics which once positioned in a desired shape can be heated to melt the polymer fibers (to provide a functionalised fiber layer comprising molten polymer fibers) and cooled to form a shaped fabric such that the shaped fabric retains the desired shape (due to the functionalised fiber layer comprising fused polymer fibers (which were melted and then cooled) in the shaped fabric). The present inventors have found that the methods and shapeable fabrics described herein also provide advantages in relation to the efficiency of production of shapeable fabrics. The shapeable fabrics described herein can be produced in a continuous in-line process in which a functionalised fiber layer as described herein is formed on a reinforcing fiber layer as described herein (or a reinforcing fiber layer is formed on a functionalised fiber layer), and the reinforcing fiber layer and functionalised fiber layer stitched together with a stitching yarn. Therefore, the shapeable fabrics described herein can be produced, for example by the method described herein, in a continuous in-line process, without the requirement of a second process step to provide a functionalised shaping component to a reinforcing fabric to form the shapeable fabric.

[0022] The invention includes the combination of the aspects and preferred features described herein except where such a combination is clearly impermissible or expressly avoided.

[0023] Brief Description of the Figures

[0024] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0025] Figure 1 is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein;

[0026] Figure 2 is a schematic diagram illustrating an exploded elevation view of an embodiment of a shapeable fabric described herein;

[0027] Figure 3a is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein;

[0028] Figure 3b is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein;

[0029] Figure 4a is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein; Figure 4b is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein;

[0030] Figure 4c is a schematic diagram illustrating a plan view of an embodiment of a shapeable fabric described herein;

[0031] Figure 5a is a schematic diagram illustrating an exploded elevation view of an embodiment of a shapeable fabric described herein; and

[0032] Figure 5b is a schematic diagram illustrating an exploded elevation view of an embodiment of a shapeable fabric described herein.

[0033] Detailed Description

[0034] Aspects and embodiments of the present invention will now be discussed. Further aspects and embodiments will be apparent to those skilled in the art.

[0035] Described herein is a shapeable fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

[0036] Reinforcing fiber layer

[0037] The shapeable fabric described herein comprises a reinforcing fiber layer comprising, consisting essentially of, or consisting of, glass fibers. The shapeable fabric described herein comprises a reinforcing fiber layer comprising, consisting essentially of, or consisting of, glass fibers oriented in a first reinforcing direction.

[0038] The reinforcing fiber layer may be a unidirectional fiber layer wherein the reinforcing fibers (comprising glass fibers) of the reinforcing fiber layer are arranged side by side and substantially parallel to one another. The reinforcing fiber layer may be described as comprising first fibers comprising glass fibers, the first fibers oriented in a first reinforcing direction. The first fibers of the reinforcing fiber layer may be arranged side by side and substantially parallel to one another.

[0039] The reinforcing fiber layer may be a multiaxial fiber layer comprising: a first layer of first fibers comprising glass fibers oriented in a first reinforcing direction; and a second layer of second fibers oriented in a second reinforcing direction. The first reinforcing direction and the second reinforcing direction may be different. The second reinforcing direction may be within 0 to 90 degrees of the first reinforcing direction, or from greater than 0 degrees to 90 degrees of the first reinforcing direction. For example, the second reinforcing direction may be within about 10 degrees to about 90 degrees of the first reinforcing direction, within about 20 degrees to about 90 degrees of the first reinforcing direction, within about 30 degrees to about 90 degrees of the first reinforcing direction, within about 40 degrees to about 90 degrees of the first reinforcing direction, within about 45 degrees to about 90 degrees of the first reinforcing direction, within about 60 degrees to about 90 degrees of the first reinforcing direction, within about 70 to about 90 degrees of the first reinforcing direction, within about 80 to about 90 degrees of the first reinforcing direction, within about 85 to about 90 degrees of the first reinforcing direction, within about 88 to about 90 degrees of the first reinforcing direction, or within about 90 degrees of the first reinforcing direction.

[0040] The reinforcing fiber layer may be a multiaxial fiber layer, for example a biaxial fiber layer, comprising a first layer of first fibers comprising glass fibers oriented in a first reinforcing direction; and a second layer of second fibers oriented in a second reinforcing direction. When the reinforcing fiber layer is a multiaxial fiber layer, for example a biaxial fiber layer, the first fibers of the reinforcing layer may be referred to as warp fibers and the second fibers of the reinforcing layer may be referred to as weft fibers, with the first fibers being arranged side by side and substantially parallel to one another and the second fibers being arranged side by side and substantially parallel to one another. When the reinforcing fiber layer is a multiaxial fiber layer, for example a biaxial fiber layer, both the first fibers and the second fibers may comprise, consist essentially of, or consist of glass fibers.

[0041] The term "glass fibers" is used herein to refer to a plurality of continuous glass filaments (the term "continuous" as used here is used to refer to a fiber / filament that has a length many times longer than its diameter, for example at least about 5000 times longer than its diameter, e.g., at least about 10 000 times longer than its diameter). The glass fibers used in the fabrics described herein may be provided as glass fiber strands (or tows). The glass fibers may be formed by a continuous manufacturing process in which molten glass passes through the holes of a "bushing," the streams of molten glass thereby formed are solidified into filaments / fibers. The glass fibers described herein (e.g., the glass fibers of the first and / or second fibers) may include a sizing on their surface, e.g., a sizing applied on the glass fibers during formation of the fibers. The sizing can include components such as a film former, lubricant, coupling agent (to promote compatibility between the glass fibers and the resin used to form a composite article comprising the hybrid fabric described herein), etc. that facilitate formation of the glass fibers and / or use thereof in a matrix resin. The glass fibers described herein may include a polyester compatible sizing or an epoxy compatible sizing.

[0042] The term "glass fiber strand" or "glass fiber tow" as used herein, refers to a bundle of continuous glass filaments. In embodiments the glass fiber strands or tows are bundles of untwisted glass filaments.

[0043] In embodiments, glass fiber strands or glass fiber tows are provided from glass fiber direct rovings. Glass fiber direct rovings are made up of a bundle of continuous untwisted (i.e., substantially parallel, or parallel) glass filaments bonded (as the glass filaments are formed) into a single strand and wound onto a bobbin.

[0044] Any suitable glass reinforcing fibers may be employed as the first or second fibers, for example, fibers made from E glass, E-CR glass (such as Advantex™ glass fibers available from Owens Corning), C glass, H glass, S glass, and AR glass types can be used.

[0045] The glass fibers referred to herein (for example, the first fibers and / or the second fibers that may be glass fibers) have a linear mass density in the range of about 50 Tex to about 5000 Tex, for example about 200 Tex to about 4800 Tex, about 300 Tex to about 2500 Tex, about 300 Tex to about 2400 Tex, or about 600 Tex to about 1200 Tex.

[0046] The reinforcing fiber layer may comprise glass fibers oriented in a first reinforcing direction along with additional fibers other than glass fibers oriented in a first reinforcing direction. The reinforcing fiber layer may comprise a first layer of first fibers comprising glass fibers oriented in a first reinforcing direction; and a second layer of second fibers oriented in a second reinforcing direction, the second fibers may comprise fibers other than glass fibers. Examples of fibers other than glass fibers include carbon fibres and / or polymer fibers such as PET.

[0047] The fibers of the reinforcing fiber layer may be held in their respective orientations in the shapeable fabric by the stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

[0048] The reinforcing fiber layer may constitute from about 20 wt.% to about 99 wt.% of the total weight of the shapeable fabric.

[0049] Functionalised fiber layer

[0050] The functionalised fiber layer of the shapeable fabric comprises, consists essentially of, or consists of a plurality of polymer fibers.

[0051] The functionalised fiber layer of the shapeable fabrics described herein, is referred to as "functionalised" due to the melting point of the polymer fibers it contains (in some examples, from which it is formed). As discussed above, melting of the polymer fibers to form a functionalised fiber layer comprising molten polymer fibers and subsequent cooling to form a functionalised fiber layer comprising fused polymer fibers has been found to change the mechanical properties of the fabric and allow for, for example, improved handleability and drapeability of the shapeable fabric combined with increased stiffness of the shaped fabric comprising a functionalised fiber layer comprising fused polymer fibers.

[0052] The functionalised fiber layer of the shapeable fabric forms an outer layer of the shapeable fabric. In some embodiments, the functionalised layer may be described as a discontinuous outer layer composed of polymer fibers (for example, continuous or chopped polymer fibers as described herein.

[0053] The functionalised fibre layer of the shapeable fabric comprises, consists essentially of, or consists of, a plurality of polymer fibers.

[0054] The functionalised fiber layer of the shapeable fabric may comprise, consist essentially of, or consist of a plurality of polymer fibers, wherein: the polymer fibers of the functionalised fiber layer are arranged substantially parallel to one another; or the polymer fibers of the functionalised fiber layer are randomly oriented chopped polymer fibers.

[0055] The functionalised fiber layer may comprise continuous polymer fibers (the term "continuous" is used here is used to refer to a fiber / filament that has a length many times longer than its diameter, for example at least about 5000 times longer than its diameter, e.g., at least about 10 000 times longer than its diameter). The polymer fibers used in the fabrics described herein may be provided as continuous polymer fiber strands (or tows), continuous polymer filaments (e.g., monofilaments), or continuous individual polymer fibers.

[0056] The functionalised fiber layer may comprise continuous polymer fibers. The continuous polymer fibers may be arranged substantially parallel to one another. The functionalised fiber layer may comprise continuous polymer fibers that are oriented in a first polymer fiber direction. The first polymer fiber direction may be different to the first reinforcing direction. The functionalised fiber layer may comprise a plurality of layers of continuous polymer fibers, the continuous polymer fibers within each layer being arranged substantially parallel to one another, while the continuous polymer fibers of one layer may be arranged in a different direction to the continuous polymer fibers of at least another of the layers of continuous polymer fibers. The functionalised fiber layer may be a multiaxial polymer fiber layer, for example a biaxial polymer fiber layer, comprising a first layer of first polymer fibers oriented in a first polymer direction; and a second layer of second polymer fibers oriented in a second polymer direction. When the functionalized fiber layer is a multiaxial polymer fiber layer, the first polymer fibers may be arranged side by side and substantially parallel to one another and the second polymer fibers may be arranged side by side and substantially parallel to one another.

[0057] The functionalised fiber layer may comprise, consist essentially of, or consist of, randomly oriented chopped polymer fibers. The terms "chopped polymer fibers" are used herein to refer to continuous polymer fibers (for example, continuous polymer fiber strands (or tows), continuous polymer monofilaments, or continuous individual polymer fibers) that have been chopped to have a length of less than about 200mm, for example a length of less than about 100mm, for example a length in the range of about 10mm to about 100mm, for example a length in the range of about 10 mm to about 75 mm. The continuous polymer fibers used to form the chopped polymer fibers may be in the form of individual polymer fibers, polymer fiber strands, or polymer monofilaments. The chopped polymer fibers, or the continuous polymer fibers chopped to form the chopped polymer fibers, may have a linear density in the range of about 50 dTex to about 2400 dTex, or about 68 dTex to abot 400 dTex. The functionalised fiber layer may comprise, consist essentially of, or consist of, randomly oriented chopped polymer fibers and have an areal weight in the range of about 5 to about 600 g / m2, for example about 5 to about 300 g / m2, preferably about 10 to about 100 g / m2, or more preferably about 10 to about 50 g / m2.

[0058] The functionalised fiber layer of the shapeable fabric described herein may comprise, consist essentially of, or consist of a plurality of polymer fibers, wherein: the polymer fibers of the functionalised fiber layer are arranged substantially parallel to one another, the polymer fibers having a linear density in the range of about 50 dTex to about 2400 dTex; or the polymer fibers of the functionalised fiber layer are randomly oriented chopped polymer fibers, the randomly oriented chopped polymer fibers having a length in the range of about 10mm to about 200mm and a linear density in the range of about 50 dTex to about 2400 dTex.

[0059] The plurality of polymer fibers of the functionalised fiber layer may be described as a plurality of independent polymer fibers. The term "independent" in relation to the plurality of polymer fibers is used herein to refer to polymer fibers that are not physically or chemically joined or attached to one another in the functionalised fiber layer that is used to form the shapeable fabric described herein, i.e., each polymer fiber of the plurality of polymer fibers not being physically or chemically joined or attached to each of the other polymer fibers of the plurality of polymer fibers. Each polymer fiber of the plurality of polymer fibers may be formed of an individual polymer fiber (for example polymer monofilaments or individual filaments) or groups of individual polymer filaments (for example, polymer fiber strands). In some embodiments, Individual polymer filaments within a polymer fiber strand may be considered to be physically or chemically joined while each of the plurality of polymer fiber strands making up the plurality of polymer fibers of the functionalised fiber layer may be independent (i.e., not physically or chemically joined). The independent polymer fibers of the functionalised fiber layer are held in place by the stitching yarn in the shapeable fabric, the stitching yarn joining the reinforcing fiber layer and the functionalised fiber layer. However, each of the plurality of independent polymer fibers of the functionalised fiber layer itself are not physically (for example, by weaving) or chemically (for example, chemically bound) joined to others of the plurality of independent polymer fibers before the reinforcing fiber layer and the functionalised fiber layer are stitched together using the stitching yarn.

[0060] The present inventors consider that the provision of a shapeable fabric as described herein comprising the functionalised fiber layer comprising polymer fibers as described herein (for example, in the form of a chopped strand fiber layer, or arranged substantially parallel to one another) provides improvements drapeability and reduced fabric stiffness compared to previous attempts to provide a shapeable fabric, at least partly due to the provision of the polymer fibers (for example independent polymer fibers) as described herein of the functionalised layer which appears to improve handleability and drapability of the fabrics which once positioned in a desired shape can be heated to melt the polymer fibers and cooled such that the shapeable fabric retains the desired shape.

[0061] The polymer fibers have a melting point of less than about 150 °C, for example less than about 140 °C, less than about 130 °C, less than about 120 °C, less than about 110 °C, less than about 100 °C less than about 90 °C, less than about 80 °C, less than about 75 °C, less than about 70 °C, or less than about 65 °C. The polymer fibers may have a melting point in the range of about 40 °C to about 150 °C, for example about 40 °C to about 140 °C, about 40 °C to about 130 °C, about 40 °C to about 120 °C, about 50 °C to about 100 °C, about 50 °C to about 90 °C, about 55 °C to about 75 °C, or about 55 °C to about 65 °C. The melting point of the polymer fibers may be determined by differential scanning calorimetry (i.e., the temperature of the peak heat flow obtained by DSC analysis). The melting point of the polymer fibers may be determined using differential scanning calorimetry (DSC) according to EN ISO 11357-3:2018 (determination of temperature and enthalpy of melting and crystallization). The melting point of the polymer fibers may be determined using differential scanning calorimetry (DSC) according to EN ISO 11357-3:2018 (determination of temperature and enthalpy of melting and crystallization) wherein the melting point is determined as the value provided on the second heating cycle. The melting point of the polymer fiber may be determined according to the EN ISO 11357-3:2018 test method by heating the shaping filament under an air flow of 80 mL / min at a heating rate of lOK / min, heating from - 60 °C to 170 °C. In embodiments, the melting point of the shaping filament may be determined according to the EN ISO 11357-3:2018 test method by heating the polymer fiber under an air flow of 80 mL / min at a heating rate of lOK / min, heating from - 60 °C to 170 °C and then holding for 5 mins at 170 °C before cooling from 170 °C to - 60 °C at a cooling rate of lOK / min and then holding for 5 mins at - 60 °C before heating from - 60 °C to 170 °C again at a heating rate of lOK / min and the melting point being determined as the value provided on the second heating cycle.

[0062] The polymer fibers may comprise or be composed of a polyester or a polyamide. For example, the polymer fibers may be composed of polycaprolactone. For example, the polymer fibers may be composed of a copolyamide. For example, the polymer fibers may be selected from polyester filaments and polyamide filaments. For example, the polymer fibers may be selected from polyester filaments and polyamide filaments having a melting point in the range of about 40 °C to about 150 °C, for example about 40 °C to about 140 °C, about 40 °C to about 130 °C, about 40 °C to about 120 °C, about 50 °C to about 100 °C, about 50 °C to about 90 °C, about 55 °C to about 75 °C, or about 55 °C to about 65 °C.

[0063] The polymer fibers may have a linear density in the range of about 50 dTex to about 1200 dTex, for example a linear density in the range of about 68 dTex to about 400 dTex.

[0064] The functionalised fiber layer may comprise, consist essentially of, or consist of, polymer fibers and have an areal weight in the range of about 5 to about 600 g / m2, for example about 5 to about 300 g / m2, preferably about 10 to about 100 g / m2, or more preferably about 10 to about 50 g / m2.

[0065] The functionalised fiber layer may be composed of polymer fibers having a melting point of less than about 150 °C.

[0066] The polymer fibers of the functionalised fiber layer described herein may be in the form of individual polymer fibers, polymer fiber strands, or polymer monofilaments, for example the polymer fibers having a linear density in the range of about 50 dTex to about 1200 dTex, or about 68 dTex to about 400 dTex.

[0067] The polymer fibers may comprise, consist essentially of, or consist of polycaprolactone filaments having a melting point in the range of about 55 °C to about 65 °C. The polymer fibers may comprise, consist essentially of, or consist of polycaprolactone filaments having a linear density in the range of about 50 dTex to about 1200 dTex. The functionalised fiber layer may constitute from about 1 wt.% to about 50 wt.% of the total weight of the shapeable fabric, for example, about 1 wt.% to about 25 wt.%, or about 2 wt.% to about 25 wt.% of the shapeable fabric.

[0068] Stitching yarn

[0069] The stitching yarn joining the reinforcing fiber layer and the functionalised fiber layer may be suitable stitching yarn. In embodiments, the stitching yarn is a polyester yarn. In embodiments, the stitching yarn has a linear mass density in the range of about 50 dTex to about 300dTex. The stitching yarn forms a stitching pattern through the shapeable fabric and joins the reinforcing fiber layer and the functionalised fiber layer. As used herein, the term "stitching pattern" refers to the pattern formed by the stitching yarn when stitching the reinforcing layer and functionalised fiber layer together. Examples of stitching pattern include a pillar stitching pattern, a tricot stitching pattern, a symmetric double tricot stitching pattern, an asymmetric double tricot stitching pattern, a symmetric stitching pattern, an asymmetric stitching pattern, or any combination thereof.

[0070] The stitching yarn may constitute from about 0.1 wt.% to about 20 wt.% of the shapeable fabric, for example from about 1 wt.% to about 5 wt.% of the shapeable fabric.

[0071] The stitching yarn may have a linear density in the range of about 50 dTex to about 200 dTex, for example a linear density in the range of about 70 dTex to about 200 dTex, a linear density in the range of about 70 dTex to about 175 dTex, or a linear density in the range of about 76 dTex to about 167 dTex.

[0072] The stitching yarn may have a melting point of at least about 180 °C, for example at least about 200 °C, or at least about 220 °C. In embodiments, the infusion stitching yarn has a melting point in the range of about 180 °C to about 400 °C, for example 200 °C to about 350 °C, or about 220 °C to about 330 °C. The infusion stitching yarn may have a melting point around 250 °C. The melting point of the stitching yarn may be determined by differential scanning calorimetry (i.e., the temperature of the peak heat flow obtained by DSC analysis). The melting point of the stitching yarn may be determined using differential scanning calorimetry (DSC) according to EN ISO 11357- 3:2018 (determination of temperature and enthalpy of melting and crystallization). The melting point of the stitching yarn may be determined using differential scanning calorimetry (DSC) according to EN ISO 11357-3:2018 (determination of temperature and enthalpy of melting and crystallization) wherein the melting point is determined as the value provided on the second heating cycle. The melting point of the stitching yarn may be determined according to the EN ISO 11357-3:2018 test method by heating the stitching yarn under an air flow of 80 mL / min at a heating rate of lOK / min, heating from - 60 °C to 400 °C. In embodiments, the melting point of the stitching yarn may be determined according to the EN ISO 11357-3:2018 test method by heating the stitching yarn under an air flow of 80 mL / min at a heating rate of lOK / min, heating from - 60 °C to 400 °C and then holding for 5 mins at 400 °C before cooling from 400 °C to - 60 °C at a cooling rate of lOK / min and then holding for 5 mins at - 60 °C before heating from - 60 °C to 400 °C again at a heating rate of lOK / min and the melting point being determined as the value provided on the second heating cycle.

[0073] The stitching yarn may comprise, consists essentially of, or consist of a polyester stitching yarn having a melting point in the range of about 180 °C to about 400 °C, for example about 200 °C to about 350 °C, and a linear density in the range of about 50 dTex to about 200 dTex.

[0074] Shapeable Fabric

[0075] Described herein is a shapeable fabric which may comprise, consist essentially of, or consist of: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

[0076] The shapable fabric may comprise, consist essentially of, or consist of: a reinforcing fiber layer as described herein; a functionalised fiber layer as described herein; and a stitching yarn joining the reinforcing fiber layer and the functionalised fiber layer.

[0077] The fibers of the reinforcing fiber layer and the fibers of the functionalised fibre layer may be held in place in the shapable fabric by the stitching yarn alone.

[0078] The shapeable fabric described herein may be described as comprising a functionalised fibre layer disposed direction on a reinforcing fiber layer, the reinforcing fiber layer and the functionalised fiber layer being joined together by a stitching yarn. The pattern formed by the stitching yarn joining together the reinforcing fiber layer and the functionalised fiber layer is described herein as a "stitching pattern".

[0079] The functionalised fiber layer and the reinforcing fiber layer of the shapeable fabric may be in direct contact with one another, i.e. the functionalised fiber layer or the reinforcing fiber layer may be disposed on the other of the functionalised fiber layer and the reinforcing fiber layer.

[0080] The functionalised fiber layer of the shapeable fabric forms at least one outer layer (or surface) of the shapeable fabric. In embodiments, the shapeable fabric may comprise a reinforcing fiber layer as described herein disposed between two functionalised fiber layers as described herein.

[0081] The shapeable fabric may comprise, consist essentially of, or consist of: from about 20 wt.% to about 99 wt.% of a reinforcing fiber layer as described herein by total weight of the shapeable fabric; from about 1 wt.% to 50 wt.% (or from about 1 wt.% to 25 wt.%; or about 2 wt.% to 25 wt.%) of a functionalised fiber layer as described herein; and from about 0.1 wt.% to about 20 wt.% (or from about 1 wt.% to about 5 wt.%) of a stitching yarn as described herein, the stitching yarn joining the reinforcing fiber layer and the functionalised fiber layer.

[0082] As discussed above, the polymer fibers of the functionalised fiber layer may be: arranged substantially parallel to one another; or randomly oriented chopped polymer fibers.

[0083] In embodiments in which the polymer fibers (which may be described as continuous polymer fibers) of the functionalised fiber layer are arranged substantially parallel to one another, the shapeable fabric may be described as a non-crimp fabric in which the glass fibers of the reinforcing fiber layer and the polymer fibers are maintained in their respective orientations by the stitching yarn.

[0084] In embodiments in which the polymer fibers (which may be described as continuous polymer fibers) of the functionalised fiber layer are arranged substantially parallel to one another, the shapeable fabric may be described as a multiaxial fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; and a functionalized fiber layer comprising polymer fibers oriented in a first polymer fiber direction. The first reinforcing direction and the first polymer fiber direction may be different. The first polymer fiber direction may be within 0 to 90 degrees of the first reinforcing direction, or from greater than 0 degrees to 90 degrees of the first reinforcing direction. For example, the first polymer fiber direction may be within about 10 degrees to about 90 degrees of the first reinforcing direction, within about 20 degrees to about 90 degrees of the first reinforcing direction, within about 30 degrees to about 90 degrees of the first reinforcing direction, within about 40 degrees to about 90 degrees of the first reinforcing direction, within about 45 degrees to about 90 degrees of the first reinforcing direction, within about 60 degrees to about 90 degrees of the first reinforcing direction, within about 70 to about 90 degrees of the first reinforcing direction, within about 80 to about 90 degrees of the first reinforcing direction, within about 85 to about 90 degrees of the first reinforcing direction, within about 88 to about 90 degrees of the first reinforcing direction, or within about 90 degrees of the first reinforcing direction.

[0085] The shapeable fabric may have an areal weight of at least about 200 g / m2, for example at least about 300 g / m2, or at least about 400 g / m2. The shapeable fabric may have an areal weight of up to about 2500 g / m2. The shapeable fabric may have an areal weight in the range of about 200 g / m2to about 2500 g / m2, for example about 300 g / m2to about 2500 g / m2, for example about 400 g / m2to about 2500 g / m2, for example about 300 g / m2to about 2000 g / m2, for example about 500 g / m2to about 1500 g / m2, for example about 500 g / m2to about 1300 g / m2, for example about 1300 g / m2to about 2500 g / m2. The areal weight of the shapeable fabric may be determined according to ISO 3374.

[0086] Fabric stack

[0087] Described herein is a fabric stack comprising a shapable fabric as described herein. The fabric stack may comprise at least two layers of fabric, with at least one layer of fabric being a shapable fabric as described herein.

[0088] A fabric stack may comprise at least two layers of a shapeable fabric as described herein wherein one layer of shapeable fabric is directly disposed on another layer of shapeable fabric. The fabric stack may comprise at least 3 layers of a shapeable fabric as described herein, for example at least 4 layers, at least 5 layers, at least 6 layers or at least 8 layers of a shapeable fabric as described herein. The fabric stack may comprise up to 50 layers of a shapeable fabric as described herein, for example, up to 30 layers, up to 25 layers, up to 20 layers up to 15 layers, up to 10 layers of a shapeable fabric as described herein. The fabric stack may comprise 2 to 50 layers of a shapeable fabric as described herein, for example 4 to 30 layers, or 6 to 25 layers of a shapeable fabric as described herein. The fabric stack may comprise a plurality of layers of shapeable fabric as described herein, wherein the each of the plurality of layers of shapeable fabric is directly disposed on another of the plurality of layers of shapeable fabric. The layers of shapeable fabric may be stacked such that the functionalised fiber layer can be used to adhere layers of the fabric stack together. For example, in embodiments in which each of the layers of shapeable fabric comprise one reinforcing fiber layer joined to one functionalised fiber layer, the layers of shapeable fabric are stacked such that the functionalised fiber layer of one layer of shapeable fabric is directly disposed on the reinforcing fiber layer of another layer of shapeable fabric.

[0089] The layers of shapeable fabric of the fabric stack may be joined or adhered together, for example by stitching or by at least partially melting a functionalised layer of a shapeable fabric of the fabric stack to adhere to another fabric layer of the fabric stack.

[0090] A fabric stack in which layers of shapeable fabric of the fabric stack are adhered to one another may be referred to herein as a "consolidated fabric stack".

[0091] The layers of shapeable fabric of the fabric stack may be adhered to one another by a suitable treatment such as heating or curing.

[0092] The layers of shapeable fabric of the fabric stack may be adhered to one another by heating the fabric stack such that the polymer fibers of at least one of the functionalised fiber layers adheres a first layer of shapeable fabric to a second layer of shapeable fabric.

[0093] The layers of shapeable fabric of the fabric stack may be adhered to one another by thermally activating the or each functionalised fiber layer, wherein thermal activation of the functionalised fiber comprises melting or at least partially melting polymer fibers of the functionalised fiber layer. The layers of shapeable fabric of the fabric stack may be adhered to one another by heating the fabric stack to a temperature of at least the melting point of the polymer fibers of the functionalised fiber layer, for example to a temperature at least about 5 °C greater than the melting point of the polymer fibers of the functionalised fiber layer, to a temperature at least about 10 °C greater than the melting point of the polymer fibers of the functionalised fiber layer, or to a temperature at least about 15 °C greater than the melting point of the polymer fibers of the functionalised fiber layer. The layers of shapeable fabric of the fabric stack may be adhered to one another by heating the fabric stack to a temperature of at least about 60 °C, for example at least about 65 °C, at least about 70 °C, or at least about 80 °C. The of shapeable fabric layers of the fabric stack may be adhered to one another by heating the fabric stack to a temperature of up to about 150 °C, for example up to about 130 °C, up to about 120 °C, or up to about 100 °C. The layers of shapeable fabric of the fabric stack may be adhered to one another by heating the fabric stack to a temperature in the range of about 60 °C to about 120 °C, for example about 65 °C to about 100 °C. The layers of shapeable fabric of the fabric stack may be adhered to one another by heating the fabric stack as described above for about 1 minute or more, for example up to about 1 hour.

[0094] The consolidated fabric stack may be produced by heating the fabric stack under vacuum, for example heating the fabric stack at a pressure below atmospheric pressure, for example a pressure in the range of about 100 mbar to about 1000 mbar, or about 100 mbar to about 900 mbar, about 100 mbar to about 800 mbar, about 100 mbar to about 700 mbar, about 100 mbar to about 600 mbar, or about 100 mbar to about 400 mbar.

[0095] The fabric stack may be exposed to increased temperature (i.e., heated) and / or reduced pressure for a time period of up to about 5 hours, for example up to about 3 hours, up to about 2 hours or up to about 1 hour to form a consolidated fabric stack. The fabric stack described herein may be impregnated with a resin and the resin cured to form a composite article. In embodiments, the resin may be a polyester resin. In embodiments, the resin may be an epoxy resin.

[0096] Process for producing a shapeable fabric

[0097] A process for producing a shapeable fabric is described herein. The process may comprise: providing a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; providing a functionalised fiber layer on the reinforcing fiber layer (the functionalised fiber layer may be provided on the top or bottom of the reinforcing fiber layer), the functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and stitching the reinforcing layer and functionalised fiber layer together using a stitching yarn to form the shapeable fabric.

[0098] The process may comprise: forming a reinforcing fiber layer as described herein, for example a reinforcing layer comprising glass fibers oriented in a first reinforcing direction, forming a functionalised fiber layer comprising polymer fibers as described herein, and stitching the reinforcing fiber layer and the functionalised fiber layer together.

[0099] The process may comprise; forming a reinforcing fiber layer as described herein; providing polymer fibers on to the reinforcing fiber layer to form a functionalised fiber layer as described herein disposed on the reinforcing fiber layer (the functionalised fiber layer may be provided on the top or bottom of the reinforcing fiber layer); and stitching the reinforcing fiber layer and the functionalised fiber layer together. The polymer fibers provided to the reinforcing fiber layer may be in the form of chopped polymer fibers as described herein. The process may comprise providing a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction (the first reinforcing direction may be aligned with the length of the fabric), depositing chopped polymer fibers on to the reinforcing fiber layer to form a functionalised fiber layer as described herein; and stitching the reinforcing fiber layer and the functionalised fiber layer together to form the shapeable fabric.

[0100] The process of producing the shapeable fabric may be a continuous process with the functionalised fiber layer being formed on the reinforcing fiber layer or vice versa and then the functionalised fiber layer and the reinforcing fiber layer being stitched together to form the shapeable fabric. This provides advantages, particularly as no further functionalisation step may be required after the fabric has been produced.

[0101] The process may comprise; forming a reinforcing fiber layer as described herein; forming a functionalised fiber layer as described herein disposed on the reinforcing fiber layer; and stitching the reinforcing fiber layer and the functionalised fiber layer together to form the shapeable fabric. The polymer fibers provided to the reinforcing fiber layer may be in the form of continuous polymer fibers as described herein. The process may comprise providing a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction (the first reinforcing direction may be aligned with the length of the fabric), providing continuous polymer fibers to form a functionalised fiber layer as described herein (for example in a first polymer fiber direction); and stitching the reinforcing fiber layer and the functionalised fiber layer together to form the shapeable fabric.

[0102] Shaped component

[0103] A shaped component comprises a fabric stack as described herein. For example, a shaped component may comprise a fabric stack as described herein wherein the or each functionalised fiber layer of the or each shapeable fabric layer comprises fused polymer fibers.

[0104] The term "fused polymer fibers" is used herein to refer to polymer fibers which have been partially melted or melted, then cooled such that polymer fibers are fused to at least one other polymer fiber.

[0105] In a shaped component as described herein, the fused polymer fibers may also be fused to at least one reinforcing fiber layer of the fabric stack forming the shaped component.

[0106] Described herein is a process for producing a shaped component, the process comprising: stacking a plurality of layers of fabric comprising at least one layer of a shapeable fabric as described herein to provide a fabric stack as described herein; shaping the fabric stack; and heating the fabric stack at a temperature up to about 180 °C.

[0107] A shaped component may be produced by: a) providing a fabric stack as described herein; b) shaping the fabric stack; and c) heating the shaped stack, for example at a temperature up to about 180 °C.

[0108] A shaped component may be produced by: a) providing a fabric stack as described herein; b) shaping the fabric stack; and c) thermally activating the or each functionalised fiber layer of the or each shapeable fabric of the fabric stack. The process described herein may comprise stacking the layers of fabric comprising at least one layer of a shapeable fabric in a mold such that the fabric stack is formed and shaped in the mold.

[0109] Heating the fabric stack may comprise heating the fabric stack at a temperature of at least about the melting point of the polymer fibers of the or each functionalised fiber layers of the or each shapeable fabric of the fabric stack. Heating the fabric stack may comprise heating the fabric stack at a temperature of at least about 50 °C, for example at least about 60 °C, at least about 70 °C, at least about 80 °C, at least about 90 °C, or at least about 100 °C. Heating the fabric stack may comprise heating the fabric stack at a temperature of up to about 160 °C, for example up to about 150 °C, or up to about 130 °C, or up to about 120 °C. Heating the fabric stack may comprise heating the fabric stack at a temperature in the range of about 50 °C to about 160 °C, for example about 50 °C to about 150 °C, about 70 °C to about 130 °C, or about 80 °C to about 120 °C.

[0110] Producing a shaped component may comprise heating the fabric stack under vacuum, for example heating the fabric stack at a pressure below atmospheric pressure, for example a pressure in the range of about 100 mbar to about 1000 mbar, or about 100 mbar to about 900 mbar, about 100 mbar to about 800 mbar, about 100 mbar to about 700 mbar, about 100 mbar to about 600 mbar, or about 100 mbar to about 400 mbar.

[0111] Producing a shaped component may comprise heating the fabric stack at a temperature up to about 160 °C, or up to about 150 °C under vacuum.

[0112] The fabric stack may be exposed to increased temperature (i.e., heated) and / or reduced pressure for a time period of up to about 5 hours, for example up to about 3 hours, up to about 2 hours or up to about 1 hour to form a shaped article. The fabric stack may be exposed to increased temperature (i.e., heated) and / or reduced pressure for a time period of at least about 10 mins, for example at least about 30 mins to form a shaped article. The fabric stack may be exposed to increased temperature (i.e., heated) and / or reduced pressure for a time period of about 10 mins to about 5 hours, for example about 30 mins to about 2 hours, or about 30 mins to about 1 hour.

[0113] Shaping the fabric stack may involves placing the fabric stack over or in a mold. Shaping the fabric stack involves placing the fabric stack over or in a mold and applying increased heat and / or reduced pressure to the fabric stack. The shaped component described herein may be impregnated with a resin and the resin cured to form a composite article.

[0114] Examples

[0115] The following illustrates examples of the fabrics and related aspects described herein. Thus, these examples should not be considered to restrict the present disclosure, but are merely in place to teach how to carry out the processes and obtain the products of the present disclosure.

[0116] Example 1

[0117] Figure 1 provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 1, shown in figure 1, comprises: a reinforcing fiber layer 20 comprising glass fibers 25 oriented in a first reinforcing direction; and a functionalised fiber layer 30 comprising a plurality of polymer fibers (for example in the form of polymer fiber tows or polymer fiber monofilaments) 35, the plurality of polymer fibers oriented in a first polymer fiber direction, the first polymer fiber direction being different to the first reinforcing direction. The reinforcing fiber layer 20 and the functionalised fiber layer 30 are stitched together with a stitching yarn (not shown in figure 1) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 1) through the shapeable fabric 10.

[0118] Example 2

[0119] Figure 2 provides an expanded illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 2, shown in figure 2, comprises: a reinforcing fiber layer 20 comprising glass fibers oriented in a first reinforcing direction (the first reinforcing direction being oriented at 90 degrees to the length / machine direction of the fabric); and a functionalised fiber layer 30 comprising a plurality of polymer fibers 35, the plurality of polymer fibers being randomly oriented chopped polymer fibers. The reinforcing fiber layer 20 and the functionalised fiber layer 30 are stitched together with a stitching yarn (not shown in figure 2) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 2) through the shapeable fabric 10.

[0120] Example 3 Figure 3a provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 3, shown in figure 3a, comprises: a reinforcing fiber layer comprising a first layer of glass fibers 25 oriented in a first reinforcing direction and a second layer of glass fibers 27 oriented in a second reinforcing direction (the first reinforcing direction being different to the second reinforcing direction); and a functionalised fiber layer comprising a plurality of polymer fibers 35, the plurality of polymer fibers oriented in a first polymer fiber direction, the first polymer fiber direction being different to the first reinforcing direction and different to the second reinforcing direction. The reinforcing fiber layer and the functionalised fiber layer are stitched together with a stitching yarn (not shown in figure 3a) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 3a) through the shapeable fabric 10.

[0121] Example 4

[0122] Figure 3b provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 4, shown in figure 3b, comprises: a reinforcing fiber layer 20 comprising glass fibers 25 oriented in a first reinforcing direction; and a functionalised fiber layer comprising a first layer of a plurality of polymer fibers 35 oriented in a first polymer fiber direction, and a second layer of a plurality of polymer fibers 37 oriented in a second polymer fiber direction (the first polymer fiber direction being different to the second polymer fiber direction), the first reinforcing direction first polymer fiber direction being different to the first polymer fiber direction and different to the second polymer fiber direction. The reinforcing fiber layer and the functionalised fiber layer are stitched together with a stitching yarn (not shown in figure 3b) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 3b) through the shapeable fabric 10.

[0123] Example 5

[0124] Figure 4a provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 5, shown in figure 4a, comprises: a reinforcing fiber layer comprising a first layer of glass fibers 25 oriented in a first reinforcing direction and a second layer of glass fibers 27 oriented in a second reinforcing direction (the first reinforcing direction being different to the second reinforcing direction); and a functionalised fiber layer comprising a plurality of polymer fibers 35, the plurality of polymer fibers oriented in a first polymer fiber direction, the first polymer fiber direction being aligned with the second reinforcing direction. The reinforcing fiber layer and the functionalised fiber layer are stitched together with a stitching yarn (not shown in figure 4a) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 4a) through the shapeable fabric 10.

[0125] Example 6

[0126] Figure 4b provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 6, shown in figure 4b, comprises: a reinforcing fiber layer comprising a first layer of glass fibers 25 oriented in a first reinforcing direction and a second layer of glass fibers 27 oriented in a second reinforcing direction (the first reinforcing direction being different to the second reinforcing direction); and a functionalised fiber layer comprising a plurality of polymer fibers 35, the plurality of polymer fibers oriented in a first polymer fiber direction, the first polymer fiber direction being different to the first reinforcing direction and different to the second reinforcing direction. The reinforcing fiber layer and the functionalised fiber layer are stitched together with a stitching yarn (not shown in figure 4b) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 4b) through the shapeable fabric 10.

[0127] Example 7

[0128] Figure 4c provides an illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 7, shown in figure 4c, comprises: a reinforcing fiber layer comprising a first layer of glass fibers 25 oriented in a first reinforcing direction, a second layer of glass fibers 1 oriented in a second reinforcing direction, and a third layer of glass fibers 28 oriented in a third reinforcing direction (the first reinforcing direction being different to the second reinforcing direction, and the third reinforcing direction being different to both the first reinforcing direction and the second reinforcing direction); and a functionalised fiber layer comprising a plurality of polymer fibers 35, the plurality of polymer fibers oriented in a first polymer fiber direction, the first polymer fiber direction being different to the first, second and third reinforcing directions. The reinforcing fiber layer and the functionalised fiber layer are stitched together with a stitching yarn (not shown in figure 4b) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 4b) through the shapeable fabric 10.

[0129] Example 8 Figure 5a provides an expanded illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 8, shown in figure 5a, comprises: a reinforcing fiber layer 20 comprising a first layer of glass fibers 25 oriented in a first reinforcing direction (the first reinforcing direction being at 90 degrees to the length of the fabric / machine direction), a second layer of glass fibers 27 oriented in a second reinforcing direction glass fibers oriented in a first reinforcing direction (the second reinforcing direction being aligned with the length of the fabric / machine direction of the fabric); and a functionalised fiber layer 30 comprising a plurality of polymer fibers 35, the plurality of polymer fibers being randomly oriented chopped polymer fibers. The reinforcing fiber layer 20 and the functionalised fiber layer 30 are stitched together with a stitching yarn (not shown in figure 5a) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 5a) through the shapeable fabric 10.

[0130] Example 9

[0131] Figure 5b provides an expanded illustration of an Example of a shapeable fabric 10 described herein. The shapeable fabric 10 of Example 9, shown in figure 5b, comprises: a reinforcing fiber layer 20 comprising a first layer of glass fibers 25 oriented in a first reinforcing direction (the first reinforcing direction being oriented at -45 degrees to the length of the fabric / machine direction), a second layer of glass fibers 27 oriented in a second reinforcing direction glass fibers oriented in a first reinforcing direction (the second reinforcing direction being oriented at 45 degrees to the length of the fabric / machine direction); and a functionalised fiber layer 30 comprising a plurality of polymer fibers 35, the plurality of polymer fibers being randomly oriented chopped polymer fibers. The reinforcing fiber layer 20 and the functionalised fiber layer 30 are stitched together with a stitching yarn (not shown in figure 5b) to form the shapeable fabric 10, the stitching yarn forming a stitching pattern (not shown in figure 5b) through the shapeable fabric 10.

[0132] Fabric stacks and shaped components can be formed as described herein from any of the shapeable fabrics described herein. For example, a plurality of shapeable fabric layers according to Examples 1-9 may be stacked such that the reinforcing fiber layer of each shapeable fabric layer is directly adjacent to (disposed on) the functionalised fiber layer of another of the shapeable fabric layers. The fabric stacks or shaped components may comprise a plurality of shapeable fabric layers, each of the shapeable fabric layers may be the same or a combination of different shapeable fabric layers may be used. 1

[0133] The inventors consider that the fabric stacks or shaped components described herein can be employed to remarkably improve lay-up speed of composite articles including the shaped components described herein. For example, shaped components comprising the shapeable fabrics described herein can be employed during wind turbine blade manufacture by incorporating a shaped component directly into a wind turbine blade during the lay-up procedure.

[0134] The present inventors also consider that providing a shapeable fabric as described provides improvements drapeability and reduced fabric stiffness compared to previous attempts to provide a shapeable fabric, at least partly due to the provision of the polymer fibers of the functionalised layer as described herein which appears to improve handleability and drapability of the fabrics which once positioned in a desired shape can be heated to melt the polymer fibers and cooled such that the shapeable fabric retains the desired shape.

[0135] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0136] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0137] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0138] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. If a standard test is mentioned herein, unless otherwise stated, the version of the test to be referred to is the most recent at the time of filing this patent application.

[0139] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word "comprise" and "include", and variations such as "comprises", "comprising", and "including" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0140] It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means for example + / - 10%.

Claims

Claims1. A shapeable fabric comprising: a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; a functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and a stitching yarn forming a stitching pattern through the shapeable fabric and joining the reinforcing fiber layer and the functionalised fiber layer.

2. A shapeable fabric according to claim 1, wherein the polymer fibers of the functionalised fiber layer are arranged substantially parallel to one another.

3. A shapeable fabric according to claim 1, wherein the polymer fibers of the functionalised fiber layer are randomly oriented chopped polymer fibers.

4. A shapeable fabric according to any of the preceding claims, wherein the functionalised fiber layer forms an outer layer of the shapeable fabric.

5. A shapeable fabric according to any of the preceding claims, wherein the polymer fibers have a melting point of less than about 120 °C.

6. A shapeable fabric according to any of the preceding claims, wherein the polymer fibers are composed of a polyester or a polyamide.

7. The shapeable fabric of any of the preceding claims, wherein the reinforcing fiber layer constitutes from about 20 wt.% to about 99 wt.% of the shapeable fabric.

8. The shapeable fabric of any of the preceding claims, wherein the functionalised fiber layer constitutes from about 1 wt.% to 25 wt.% of the shapeable fabric.

9. The shapeable fabric of any of the preceding claims, wherein the polymer fibers have a linear density in the range of about 50 dTex to about 2400 dTex.

10. The shapeable fabric of any of the preceding claims, wherein the functionalised fiber layer has an areal weight in the range of about 5 to about 600 g / m2.

11. The shapeable fabric of any of the preceding claims, wherein the areal weight of the shapeable fabric is in the range of about 400 g / m2to about 2500 g / m2.

12. A fabric stack comprising at least two layers of fabric, at least one layer of fabric being a layer of a shapeable fabric according to any of claims 1 to 11.

13. A fabric stack according to claim 12 comprising at least two layers of a shapeable fabric according to any of claims 1 to 11, wherein one layer of shapeable fabric according to any of claims 1 to 11 is directly disposed on another layer of shapeable fabric according to any of claims 1 to 11.

14. A shaped component comprising a fabric stack according to claim 12 or claim 13, wherein the or each functionalised fiber layer comprises fused polymer fibers.

15. A process for producing a shapeable fabric, the process comprising: providing a reinforcing fiber layer comprising glass fibers oriented in a first reinforcing direction; providing a functionalised fiber layer on the reinforcing fiber layer, the functionalised fiber layer comprising a plurality of polymer fibers, the polymer fibers having a melting point of less than about 150 °C; and stitching the reinforcing layer and functionalised fiber layer together using a stitching yarn to form a shapeable fabric, the stitching yarn forming a stitching pattern through the shapeable fabric.

16. A process for producing a shaped component, the process comprising: stacking a plurality of layers of fabric to provide a fabric stack, at least one layer of fabric being a layer of a shapeable fabric according to any of claims 1 to 11; shaping the fabric stack; and heating the fabric stack at a temperature up to about 180 °C.

17. A process according to claim 16 comprising heating the fabric stack at a temperature up to about 160 °C under vacuum.

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