Method for producing polymeric leading edge protection sheet with chamfered side edges

Abstract

Disclosed herein is a method for producing a polymeric leading edge protection sheet having chamfered side edges for a wind turbine blade.

Description

Technical Field

[0001] The present invention relates to a method for producing a polymer leading edge protection sheet having chamfered side edges for a wind turbine blade. Background Art

[0002] Rotor blades, such as those found in wind turbines and helicopters, are subject to varying environmental conditions, including erosion caused by the impact of airborne materials such as rain, sand, dust, and other debris. The leading edges of wind turbine blades are particularly susceptible to damage from erosion. As rotor blades become longer, blade tip speeds become higher, and wind turbines are erected in increasingly harsh and remote locations—including offshore locations—leading-edge erosion only becomes a greater problem.

[0003] Industry has sought to prevent this erosion through membranes, coatings, and other methods. In some examples, prefabricated segments made of a strong yet soft and flexible polymer shell are applied to the leading edges of wind turbine blades. The shell is designed and sized to absorb kinetic energy from rain, hail, and airborne particles. Thus, it provides optimal protection for the blade's rigid fiberglass surface.

[0004] In some examples, the film is applied to the leading edge of a wind turbine blade, wherein the film is applied around the leading edge of the wind turbine blade and adhered to the blade via an adhesive. The outermost surface of a commercial tape is typically planar and, in its most basic configuration, comprises a polymer film as a protective layer and an adhesive layer for attachment to the wind turbine blade. Some films have an outer top surface of the film that has an overall profile that is convexly curved or convexly trapezoidal.

[0005] Forming the outer top surface typically involves shaping the surface using a cutter after production. However, this results in an uneven outer surface across the membrane.

[0006] Therefore, there is a need for an improved method for producing a polymeric leading edge protection sheet for wind turbine blades that provides improved smoothness to the film on the outer surface. Summary of the Invention

[0007] Disclosed herein in a first aspect is a method for producing a polymer leading edge protection sheet having chamfered side edges for a wind turbine blade.By wind turbine is meant wind turbines of a wide range of sizes.

[0008] The method comprises the following steps:

[0009] - providing a polymer material sheet comprising a first major surface and a second major surface, each major surface having a width extending in a width direction between side edges of the polymer material sheet, wherein the first major surface and the second major surface are oppositely oriented, wherein the polymer material sheet has a thickness, and - forming the polymer material sheet into a polymer leading edge protection sheet by positioning the polymer material sheet between at least a pair of rollers.

[0010] At least one pair of rollers comprises a first roller and a second roller, wherein:

[0011] o The first roller includes a first forming surface extending between opposite ends of the first roller, which

[0012] wherein the first forming surface extends concavely between said opposite ends;

[0013] o the second roller includes a second forming surface extending between opposite ends of the second roller;

[0014] o the first forming surface and the second forming surface are arranged opposite each other; and

[0015] o During the rotation of the first and second rollers, the thickness of the polymer material sheet is varied by means of the forming surfaces of the rollers to obtain a polymer leading edge protection sheet with chamfered side edges, the polymer leading edge protection sheet having a reduced thickness at the side edges when compared to the sheet thickness at the central area.

[0016] By concavely extending the first forming surface, it is meant that at least a portion of the middle section of the first roller has a smaller diameter than the end sections of the first roller. The roller may have a continuously decreasing diameter when measured from the side edges toward the center of the roller. Alternatively, the roller may have a continuously decreasing diameter when measured from the side edges toward a middle section across a certain width of the roller, such as, for example, a middle section spanning 10% of the roller width.

[0017] By using at least one pair of rollers to change and shape the polymer leading edge protection sheet, a polymer leading edge protection sheet having a specific surface profile can be obtained by selecting the roller forming surface to match the requirements. This provides a smoother surface profile on the polymer leading edge protection sheet compared to a method of shaping a polymer leading edge protection sheet having the same thickness into a polymer leading edge protection sheet having chamfered edges by removing a portion of the polymer leading edge protection sheet after production. The use of rollers ensures that the polymer leading edge protection sheet accurately obtains the desired surface profile shape because the polymer leading edge protection sheet can be allowed to cool during the process of providing the polymer material sheet between the at least one pair of rollers. In addition, by the above method, an improved method for producing a polymer leading edge protection sheet having improved smoothness on the outer surface due to the use of at least one pair of rollers is obtained.

[0018] The concavely extending first forming surface may be curved. Thus, in one or more examples, the first forming surface of the first roller is curved. Curved means that the surface deviates from a straight line or a plane surface without sharp breaks or angles.

[0019] In a second aspect, the present invention discloses a polymer leading edge protection sheet obtained according to the above method.

[0020] Disclosed herein in a third aspect is a wind turbine blade having a polymer leading edge protection sheet according to above.

[0021] The provision of the polymer material sheet can be obtained in a variety of ways. One way is to melt the granular material and form the granular material into a material sheet. Therefore, in one or more examples, the method further includes:

[0022] - melting the granular polymer material through an extruder process to obtain a molten polymer material having a predetermined hardness, thereby obtaining a plasticized polymer material; and

[0023] - pressing the plasticized polymer material through a flat die to form the plasticized polymer material into a sheet of polymer material.

[0024] After pressing the plasticized polymer material through the flat die, the plasticized polymer material may be pulled through rollers to form the plasticized polymer material into a sheet of polymer material.

[0025] In the extruder process, the granular polymer material (such as thermoplastic polyurethane material) can be softened and melted by the frictional heat generated by the use of the screw or screw shaft to compress the material by rotation in the extruder barrel. During the extruder process, the granular polymer material is heated and the resulting plasticized polymer material is obtained at an elevated temperature. The plasticized polymer material can be maintained at an elevated temperature in a flat die by one or more electrically heated zones, which ensures that the plasticized polymer material remains in a moldable / plasticized state.

[0026] Prior to melting the granular polymer material, the granular polymer material may be dried to reduce or remove any moisture. Thus, in one or more examples, the method further comprises providing the granular polymer material and drying the granular polymer material to a moisture level of 0.02 wt % or less prior to melting the granular polymer material. Drying may be performed, for example, by air drying in a desiccant air dryer.

[0027] In one or more examples, the polymer material is a polyurethane material. The polyurethane material can be a polyurethane thermoplastic material. Therefore, in one or more examples, the polymer leading edge protection sheet is a polyurethane leading edge protection sheet. The polyurethane thermoplastic material can contain a polyol, a chain extender and an aliphatic isocyanate. The polyurethane leading edge protection sheet can be a thermoplastic polyurethane leading edge protection sheet. Polyurethane can be a commonly used polymer material as the main material in the polymer leading edge protection sheet. However, alternative polymer materials can also be used, including thermoplastic olefins, styrene block copolymers, thermoplastic copolyesters, silicone thermoplastics, silicone polyoxamides, aliphatic polyether-based thermoplastic polyurethanes, copolyester ethers, cross-linked polyurethanes, polyureas, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene butylene-styrene block copolymers (SEBS) and styrene-ethylene / propylene-styrene (SEPS) block copolymers. Combinations of any polymer materials in the polymer material can also be envisioned.

[0028] In one or more examples, the polymer material is a polyurethane material, and the granular polyurethane material is an aliphatic thermoplastic polyurethane (TPU) made from a polyol such as a difunctional polyol, a butanediol chain extender, and an aliphatic isocyanate. The so-called "difunctional polyol" means that the thermoplastic polyurethane polymer has two reactive groups per molecule. Typically, thermoplastic polyurethanes are linear. Aliphatic thermoplastic polyurethanes (TPU) can be a commonly used granular polyurethane material. However, alternative granular polymer materials can also be used, including particles of the following: thermoplastic olefins, styrene block copolymers, thermoplastic copolyesters, silicone thermoplastics, silicone polyoxamides, aliphatic polyether-based thermoplastic polyurethanes, copolyester ethers, cross-linked polyurethanes, polyureas, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene butylene-styrene block copolymers (SEBS), and styrene-ethylene / propylene-styrene (SEPS) block copolymers. Combinations of any polymer granular materials in the polymer granular material are also conceivable.

[0029] In one or more examples, the polymer material is a polyurethane material, and the granular polyurethane material further comprises one or more additives, such as a UV absorber, an antioxidant, and / or a pigment. The amount of the additives may vary from 0.1 wt% to 50 wt%. The additives may also include dyes, fillers, stabilizers, or combinations thereof.

[0030] In one or more examples, the polymer material is a polyurethane material, and the granular polyurethane material does not contain a release agent. The release agent may be omitted to ensure that the subsequent bond with the pressure-sensitive adhesive is secure.

[0031] In one or more examples, the polymeric leading edge protection sheet is characterized by the following physical properties:

[0032] - Maximum thickness between 0.8mm and 2.0mm;

[0033] - a Shore A hardness between 65 and 75 as measured by ISO 868;

[0034] - when measured using ISO 37 / 1A at 23°C, the elongation is greater than 400 mm;

[0035] - the speed of sound is less than 1700 m / s as measured by ISO 16810 and ISO 16811; and

[0036] - Erosion resistance at 150 m / s for more than 8 hours, as measured by DNV-RP-0171.

[0037] In one or more examples, the polymeric leading edge protection sheet is characterized by the following physical properties:

[0038] - Maximum thickness between 0.7mm and 2.0mm;

[0039] - a Shore A hardness between 68 and 78, as measured by ISO 868;

[0040] - when measured using ISO 37 / 1A at 23°C, the elongation is greater than 400 mm;

[0041] - The speed of sound is less than 1700 m / s as measured by ISO 16810 and ISO 16811; and

[0042] - Erosion resistance at 140 m / s exceeding 10 hours, the erosion resistance being measured according to DNV-RP-0171.

[0043] The maximum thickness refers to the maximum thickness of the leading edge protection sheet. This maximum thickness is typically found in the center of the width of the polymer leading edge protection sheet. The thickness at the chamfered edges will always be less than the maximum thickness of the polymer leading edge protection sheet. The maximum thickness will generally depend on the hardness of the material. Typically, when the material hardness is between 65 and 78, the maximum thickness should be less than 2 mm, most likely less than 1.5 mm, or even less than 1.2 mm.

[0044] In one or more examples, the polymer leading edge protection sheet has a minimum thickness greater than 0.01 mm, such as greater than 0.05 mm, or greater than 0.10 mm. The minimum thickness refers to the smallest thickness along the leading edge protection sheet. The minimum thickness will typically be found at the chamfered edge of the polymer leading edge protection sheet. The maximum thickness of the polymer leading edge protection sheet will always be greater than the minimum thickness at the chamfered edge. The minimum thickness will typically depend on the hardness of the material.

[0045] In one or more examples, the polymer leading edge protection sheet has a width in the width direction between the side edges of the polymer leading edge protection sheet, the width including a first trisection and a second trisection, wherein the first trisection and the second trisection are each located near the side edges of the polymer leading edge protection sheet corresponding to the first trisection and the second trisection, wherein a remaining trisection is arranged between the first trisection and the second trisection, wherein a thickness variation of the polymer leading edge protection sheet in the width direction is greater in the first trisection and the second trisection than in the remaining trisection. The thickness variation of the polymer leading edge protection sheet in the remaining trisection of the polymer leading edge protection sheet corresponds to the thickness variation in the middle section of the polymer leading edge protection sheet. If the polymer leading edge protection sheet is substantially flat over a large area around the middle portion of the polymer leading edge protection sheet, the thickness variation in the trisection can be close to zero. If the polymer leading edge protection sheet has a continuously varying thickness profile, wherein the thickness profile has a maximum value in the middle region of the polymer leading edge protection sheet, then the thickness variation in the remaining thirds will be greater than zero. However, the thickness variation in the remaining thirds will generally be less than the thickness variation in the first and second thirds of the polymer leading edge protection sheet.

[0046] In one or more examples, the remaining third has a maximum thickness of less than 1.5 mm.Thus, the polymer leading edge protection sheet may be characterized by a maximum thickness between 0.7 mm and 1.5 mm, such as between 0.8 mm and 1.5 mm.

[0047] In one or more examples, the remaining third has a maximum thickness of less than 1.2 mm.Thus, the polymer leading edge protection sheet may be characterized by a maximum thickness between 0.7 mm and 1.5 mm, such as between 0.8 mm and 1.2 mm.

[0048] In one or more examples, the remaining third has a maximum thickness of less than 1 mm.Thus, the polymer leading edge protection sheet may be characterized by a maximum thickness between 0.7 mm and 1.5 mm, such as between 0.8 mm and 1.0 mm.

[0049] In one or more examples, the first and second thirds have a minimum thickness of less than 0.5 mm. Thus, if the maximum thickness is between 0.7 mm and 1.5 mm, such as between 0.8 mm and 2.0 mm, the difference between the thickness of the polymer leading edge protection sheet across the width of the sheet may be at least 1.5 mm.

[0050] In one or more examples, the first and second trisections have a minimum thickness greater than 0.01 mm, such as greater than 0.05 mm, such as greater than 0.10 mm.

[0051] In one or more examples, the polymer leading edge protection sheet has a width in the width direction between the side edges of the polymer leading edge protection sheet, the width including a first quarter and a second quarter, wherein the first quarter and the second quarter are each located near the side edge of the polymer leading edge protection sheet corresponding to the first quarter and the second quarter, wherein the remaining half is arranged between the first quarter and the second quarter, wherein the thickness variation of the polymer leading edge protection sheet in the width direction is greater in the first quarter and the second quarter than in the remaining half. The thickness variation of the polymer leading edge protection sheet in the remaining half corresponds to the thickness variation in the middle section of the polymer leading edge protection sheet. If the polymer leading edge protection sheet is substantially flat over a large area around the middle portion of the polymer leading edge protection sheet, the thickness variation in the remaining half can be close to zero. If the polymer leading edge protection sheet has a continuously varying thickness profile, wherein the thickness profile has a maximum value in the middle region of the polymer leading edge protection sheet, the thickness variation in the remaining half will be greater than zero. However, the thickness variation in the remaining half will generally be less than the thickness variation at the first and second quarters of the polymeric leading edge protection sheet.

[0052] In one or more examples, the polymer leading edge protection sheet has a Shore A hardness of less than or equal to 78. The Shore A hardness is measured by ISO 868.

[0053] In one or more examples, the polymer leading edge protection sheet has a Shore A hardness of less than or equal to 75. The Shore A hardness is measured by ISO 868.

[0054] In one or more examples, the second forming surface of the second roller extends cylindrically between the opposite ends. By cylindrical is meant that the second roller has a diameter that does not vary or varies only slightly over the length of the roller. Alternatively, the second forming surface can be slightly convex.

[0055] In one or more examples, the first roller and the second roller each have a longitudinal axis (LA1, LA2) extending between the opposite ends, wherein the longitudinal axes (LA1, LA2) are substantially parallel. Thus, the two rollers can be positioned relative to each other with the two rollers having an equal distance between the two ends of the rollers. If a polymeric leading edge protection sheet is relevant in which one side edge is thinner than the other side edge, the distance between the first roller and the second roller at one end of the roller can be slightly greater than the distance between the first roller and the second roller at the other end of the roller.

[0056] In one or more examples, the second forming surface of the second roller is smooth. The polymer front edge protection sheet will typically have a flat surface and a curved surface. When the polymer front edge protection sheet is arranged between the first pair of rollers, the first forming surface of the first roller will typically contact the curved surface of the polymer front edge protection sheet, and the second forming surface of the second roller will typically contact the flat surface of the polymer front edge protection sheet. After producing the polymer front edge protection sheet as described above, additional layers, such as adhesive layers, can be added to the flat surface of the polymer front edge protection sheet. The second forming surface of the second roller having a smooth surface provides a smooth flat surface on the polymer front edge protection sheet. If a pressure-sensitive adhesive is applied to the front edge protection sheet on its flat surface side after production, it is key to make the contact area as large as possible, which is best achieved by having a smooth surface with low roughness on the flat surface of the polymer front edge protection sheet. If there is a high degree of roughness on the second roller, the pressure-sensitive adhesive (PSA) applied to the polymer front edge protection sheet after leaving the roller may only attach itself to the peaks and will not contact the valleys on the surface of the polymer front edge protection sheet. This means that the total contact area between the polymeric leading edge protection sheet and the PSA is less than 100%.

[0057] The extruded leading edge protection sheet can be shaped by pushing a heat-plasticized thermoplastic material through a flat die tool. The heat-plasticized preformed sheet can be pulled away from the hot flat die, onto and through a first pair of rollers, where it cools and defines its final shape. The pulling can be performed by rotating the rollers.

[0058] Guiding the polymer material sheet through the first pair of rollers, i.e., between the first roller and the second roller, can be accomplished by pushing or pulling the polymer material sheet. A combination of both pushing and pulling the sheet between the rollers in the first pair of rollers can also be employed. Thus, in one or more examples, forming the polymer material sheet into the polymer leading edge protection sheet is accomplished by pulling and / or pushing the polymer material sheet through at least one pair of rollers. The first roller can pull the polymer material sheet through the at least one pair of rollers.

[0059] Alternatively, the second roller can be a roller that pulls the polymer material sheet through the at least one pair of rollers. Still alternatively, both rollers in the at least one pair of rollers can pull the polymer material sheet through the at least one pair of rollers. Thus, in one or more examples, forming the polymer material sheet into the polymer leading edge protection sheet is achieved by pulling the polymer material sheet through the at least one pair of rollers, wherein at least the first roller and / or the second roller pulls the polymer material sheet through the at least one pair of rollers.

[0060] In one or more examples, forming the polymeric material sheet into the polymeric leading edge protection sheet is achieved by pushing the polymeric material sheet through at least one pair of rollers, wherein at least a flat die / extruder pushes the polymeric material sheet through the at least one pair of rollers. The polymeric material sheet can be pushed out of the flat die by one or more rotating screws. When the polymeric material sheet enters the space between the first pair of rollers, the polymeric material sheet can be pulled through the rollers at the same speed as the rotating screws are delivering more of the polymeric material sheet.

[0061] In one or more examples, shaping the polymer material sheet into the polymer leading edge protection sheet is achieved by allowing the polymer material sheet to fall into a cavity between at least one pair of rollers. This process is also known as using a hanger to shape the polymer leading edge protection sheet.

[0062] In one or more examples, the method further includes positioning the polymer leading edge protection sheet between a second pair of rollers, the second pair of rollers comprising a third roller and one of the first and second rollers. The polymer leading edge protection sheet is thereby first guided through the first pair of rollers and then guided through the second pair of rollers. By means of the second pair of rollers sharing one of the rollers with the first pair of rollers, the polymer leading edge protection sheet will generally follow the roller as the rollers rotate and is therefore guided through the second pair of rollers after leaving the space between the first pair of rollers. The third roller may be similar to the first roller or the second roller in the sense that the third roller has a similar forming surface. Thus, in the examples, the third roller comprises a third forming surface extending between opposite ends of the third roller, wherein the third forming surface extends concavely between the opposite ends. Alternatively, in the examples, the third roller comprises a third forming surface extending between opposite ends of the third roller, wherein the third forming surface extends cylindrically between the opposite ends.

[0063] Alternatively, the second pair of rollers may include a third roller and a fourth roller, wherein neither the third roller nor the fourth roller is the first roller nor the second roller.

[0064] In one or more examples, the first, second, and / or third rollers are cooled. By cooling one or more of the rollers, the polymer leading edge protection sheet entering the first pair of rollers—and possibly subsequently entering the second pair of rollers—will cool more quickly as it passes through the rollers, with the polymer leading edge protection sheet having an elevated temperature, thereby allowing it to be formed into a polymer leading edge protection sheet with chamfered side edges. This can improve control over achieving the desired surface profile shape. Cooling can be achieved by using cooling water that circulates within one or more of the rollers. Alternatively, a different cooling liquid, such as, for example, ethylene glycol, can be used instead of cooling water.

[0065] The method may further comprise providing the polymeric leading edge protection sheet through a quality control section which ensures that the polymeric leading edge protection sheet meets performance specifications. This is typically performed after exiting one or more pairs of rollers.

[0066] The method may further include winding the polymeric leading edge protection sheet onto one or more rollers prior to adding the adhesive and / or shortening the polymeric leading edge protection sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Various examples are described below with reference to the accompanying drawings. The same reference numerals always refer to the same elements. Therefore, the same elements will not be described in detail for the description of each figure. It should also be noted that the drawings are intended only to facilitate the description of the examples. The drawings are not intended to serve as an exhaustive description of the claimed invention or as a limitation on the scope of the claimed invention. In addition, the illustrated examples do not need to have all the aspects or advantages shown. Aspects or advantages described in conjunction with a particular example are not necessarily limited to that example and can be practiced in any other example, even if not illustrated as such, or even if not explicitly described as such.

[0068] Figure 1 A system for producing a polymer leading edge protection sheet having chamfered side edges is shown.

[0069] Figure 2 A method for producing a polymeric leading edge protection sheet with chamfered side edges is schematically shown.

[0070] Figure 3 The flat die is shown in perspective.

[0071] Figures 4A to 4C A different system comprising a flat die and a roller system is shown in side view.

[0072] Figures 5A to 5B The first pair of rollers is shown with and without a leading edge protection sheet between the rollers.

[0073] Figures 6A to 6C Three different sets of first and second pairs of rollers are shown.

[0074] 7A to 7D Different examples of leading edge protection sheets with chamfered side edges are shown.

[0075] Figure 8 A system for producing a polymer leading edge protection sheet having chamfered side edges is shown. DETAILED DESCRIPTION

[0076] Illustrative examples will now be described more fully below with reference to the accompanying drawings. In this regard, the present examples may have different forms and should not be construed as being limited to the description set forth herein. Therefore, the examples will be described below solely with reference to the accompanying drawings to illustrate various aspects. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of..." when following a list of elements modify the entire list of elements rather than modifying the individual elements of the list.

[0077] In the accompanying drawings, for the sake of clarity and easy description of multiple layers and regions, its thickness is illustrated in an amplified manner. When a layer, region, element or plate is referred to as being "on" another layer, region, element or plate, the layer, region, element or plate can be directly located on another layer, region, element or plate, or there can be an intermediate layer, region, element or plate between the layer, region, element or plate and another layer, region, element or plate. On the contrary, when a layer, region, element or plate is referred to as being "directly located on another layer, region, element or plate", there can be no intermediate layer, region, element or plate between the layer, region, element or plate and the another layer, region, element or plate. In addition, when a layer, region, element or plate is referred to as being "below" another layer, region, element or plate, the layer, region, element or plate can be directly located below another layer, region, element or plate, or there can be an intermediate layer, region, element or plate between the layer, region, element or plate and another layer, region, element or plate. In contrast, when a layer, region, element or panel is referred to as being "directly beneath" another layer, region, element or panel, there are no intervening layers, regions, elements or panels present.

[0078] For ease of description, spatially relative terms such as "lower" or "bottom" and "upper" or "top," "below," "below," "less," and "above" may be used herein to describe the relationship between one element or component and another element or component as illustrated in the accompanying drawings. It will be understood that spatially relative terms are intended to encompass different orientations of the device when in use or operation, in addition to the orientation depicted in the accompanying drawings. For example, if the device illustrated in the accompanying drawings is turned over, an element described as being on the "lower" side of another element or being "below" or "below" another element will be oriented to be on the "upper" side of the other element or being "above" another element. Thus, the illustrative terms "below" or "below" can include both a "lower" orientation position and an "upper" orientation position, depending on the particular orientation of the drawing. Similarly, if the device in one of the drawings is turned over, an element described as being "below" or "below" another element will be oriented to be "above" the other element. Thus, the exemplary terms "below" or "below" can include both an above and below orientation, and therefore, spatially relative terms can be interpreted differently depending on the orientation described.

[0079] Throughout the specification, when an element is referred to as being “connected” to another element, the element is “directly connected” to the other element or “electrically connected” to the other element with one or more intervening elements interposed therebetween.

[0080] The terms used herein are for the purpose of describing specific examples only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" as used herein are intended to include the plural forms, i.e., include "at least one". "At least one" should not be interpreted as limiting "one" or "a". It will also be understood that when used in this specification, the terms "comprise", "including", "comprising" and / or "comprising" indicate the presence of the described features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0081] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. Thus, the "first element" discussed below could be referred to as the "second element" or the "third element," and without departing from the teachings herein, the "second element" and the "third element" could also be referred to as the "first element."

[0082] As used herein, "about" or "approximately" is inclusive of the stated value and means within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art, taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0083] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It will also be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted as idealized or overly formalized unless expressly defined in this specification.

[0084] Exemplary examples are described herein with reference to cross-sectional views of schematic diagrams as idealized examples, wherein the same reference numerals refer to the same elements throughout the specification. Therefore, variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are expected. Therefore, the examples described herein should not be interpreted as being limited to the specific shapes of the regions as illustrated herein, but rather include shape deviations, for example, caused by manufacturing. For example, an area illustrated or described as flat may have rough features and / or nonlinear features. In addition, illustrated sharp angles may be rounded. Therefore, the areas illustrated in the figures are schematic in nature, and their shapes are not intended to be the precise shapes of the illustrated areas and are not intended to limit the scope of the present claims. In order to specifically describe the exemplary examples of the present disclosure, some parts that are not relevant to the description may not be provided.

[0085] Figure 1 A system for producing a polymer leading edge protection sheet 120 having chamfered side edges 122 is shown, and Figure 2 Schematically shows the use of Figure 1 A method for producing a polymer leading edge protection sheet using a system. Figure 1 The system shown includes an extrusion system 10 , a screen system 20 , a flat die 50 , a roller system 60 , a conveyor 70 , a quality control section 80 , and a pulling roller unit 90 .

[0086] When producing the polymeric leading edge protection sheet 120 , the polymeric material sheet 106 is provided and formed 206 into the polymeric leading edge protection sheet 120 by positioning the polymeric material sheet 106 between at least one pair of rollers in the roller system 60 .

[0087] The polymer material sheet 106 can be obtained in a variety of different ways, for example Figure 1 and Figure 2As shown, the granular polymer material 100 is obtained by melting 202 a molten polymer material 102 having a predetermined hardness in an extruder process in an extrusion system 10, thereby obtaining a plasticized polymer material 104, and then pressing 204 the plasticized polymer material 104 through a flat die 50 to form the plasticized polymer material 104 into a polymer material sheet 106. During the extruder process, the granular polymer material 100 can be softened and melted by frictional heat generated by compression and rotation of a screw or screw shaft in an extruder barrel. Prior to melting 202 the granular polymer material 100, the granular polymer material can be air-dried, for example, in an air dryer to a moisture level of 0.02 wt% or less.

[0088] like Figure 3 As shown, shaping the polymer material sheet 106 into the polymer leading edge protection sheet 120 can be achieved by pulling and / or pushing the polymer material sheet 106 through at least one pair of rollers 610, 620. When the polymer material sheet 106 is pulled through the at least one pair of rollers 610, 620, at least the first roller 610 and / or the second roller 620 pulls the polymer material sheet 106 through the at least one pair of rollers 610, 620.

[0089] After the polymer leading edge protection sheet 120 is obtained, it can be directed 208 via a conveyor 70 through a quality control section 80, which ensures the performance specifications / required specifications of the polymer leading edge protection sheet 120. The polymer leading edge protection sheet 120 can then be wound 210 onto one or more rollers 90 before adding adhesive and / or shortening the polymer leading edge protection sheet 120. The polymer leading edge protection sheet 120 can be cut into smaller pieces.

[0090] Figure 3 A portion of the flat die 50 is shown in perspective view. Figures 4A to 4C , a flat die is shown in side view together with three different roller systems 60. The flat die 50 includes an inlet channel 502 through which the plasticized polymer material 104 is guided via a side surface 504 onto a flat outlet channel 506. The polymer material sheet 106 exits the flat die 50 at an exit edge 508 of the flat outlet channel. The plasticized polymer material 104 is maintained at an elevated temperature in the flat die 50 by an electric heating zone 510, which ensures that the plasticized material remains in a moldable / plasticized state.

[0091] Figure 4AThe illustrated roller system 60 includes a plurality of rollers 610, 620, and 630 arranged in pairs. The pairs of rollers include a first pair of rollers 61, which includes a first roller 610 and a second roller 620. The first rollers 610 and the second rollers 620 are arranged such that the polymer material sheet 106 exiting the flat die 50 first passes between the first rollers 610 and the second rollers 620 before passing between the second pair of rollers 62. Typically, if these rollers are cooled, the warm polymer material sheet 106 exiting the flat die 50 is cooled upon contact with the rollers. The second pair of rollers 62 includes a second roller 620 and a third roller 630. The first roller 610 and the third roller 630 rotate in the same direction, while the second roller 620 rotates in a direction opposite to the first roller 610 and the third roller 630. The first major surface 108 of the polymer material sheet 106 will contact the first roller 610, and the second major surface 110 will contact the second roller 620. The surfaces of the first roller 610 and the second roller 620 generally define the shape of the polymeric leading edge protection sheet 120 that exits the space between the two rollers 610 , 620 .

[0092] and Figure 4A Compared to the roller system 60 shown, Figure 4B The roller system 60 shown includes one less roller, there is only one roller pair 61 including a first roller 610 and a second roller 620. Figure 4B Compared with the roller system 60 in Figure 4C The roller system 60 in FIG. 5 includes two roller pairs 61 and 62. The first pair of rollers 61, which includes a first roller 610 and a second roller 620, is arranged so that the polymer material sheet 106 leaving the flat die 50 first passes between the first roller 610 and the second roller 620 before passing between the second pair of rollers 62. The second pair of rollers 62 includes a third roller 630 and a fourth roller 640. The first roller 610 and the third roller 630 rotate in the same direction, while the second roller 620 and the fourth roller 640 rotate in a direction opposite to the direction of the first roller 610 and the third roller 630. The two pairs of rollers 61 and 62 are arranged in parallel. Therefore, Figure 4A Compared to the roller system 60 of FIG. 5 , the same rollers are not shared between the two pairs of rollers 61 , 62 .

[0093] Figures 4A to 4C The illustrated rollers 610 , 620 , 630 , 640 are shown as viewed from one of the ends 614 , 624 , 634 , 644 of each roller 610 , 620 , 630 , 640 extending therebetween.

[0094] Figure 5AA first pair of rollers 61 is shown, comprising a first roller 610 and a second roller 620. The first roller 610 includes a first forming surface 612 extending concavely between opposite ends 614 of the first roller 610. The fact that the first roller 610 is concave means that the middle section 616 of the first roller 610 has a smaller diameter than the end sections 618 of the first roller 610. This can also be seen in the figure, where the concave shape is clearly visible. The first forming surface 612 can be curved, as shown in the figure, where curved means that the surface deviates from a straight or planar surface without sharp breaks or angles. The length of the first roller 610 is shown as a first length LA1 extending through the middle of the first roller 610.

[0095] The second roller 620 includes a second forming surface 622 extending between opposite ends 624 of the second roller 620. The second forming surface 622 will generally extend cylindrically between the opposite ends 624. By cylindrical, it is meant that the second roller 620 has a diameter that does not vary, or varies only slightly, along the second length LA2 of the second roller 620. Alternatively, the second forming surface 622 may be slightly convex.

[0096] like Figure 5A As shown, the first forming surface 612 and the second forming surface 622 are arranged opposite to each other. Figure 5B As shown, the polymer material sheet 106 passes through the space between the first forming surface 612 and the second forming surface 622 to obtain a polymer leading edge protection sheet 120 having chamfered side edges 122 defined by the first forming surface 612 extending concavely between the opposite ends 614 of the first roller 610. This results in the polymer leading edge protection sheet 120 having a reduced thickness at the side edges 122 when compared to the thickness of the sheet at the central region 124.

[0097] Figures 6A to 6C There are shown three rollers 610, 620, 630 arranged as a first set of rollers 61 and a second set of rollers 62. The first set of rollers 61 comprises also Figure 5A A first roller 610 and a second roller 620 are shown. Figures 6A to 6B The second set of rollers 62 shown includes a third roller 630 and a Figure 5A The second roller 620 is shown. The third roller 630 includes a third forming surface 632 extending between opposite ends 634 of the third roller 630. The second forming surface 622 and the third forming surface 632 are disposed opposite each other.

[0098] Figure 6A The third forming surface 632 on the third roller 630 is shown extending cylindrically between opposite ends 634. Alternatively, the third forming surface 632 may be slightly convex. Figure 6BA third forming surface 632 on the third roller 630 is shown extending concavely between opposite ends 634 of the third roller 630 .

[0099] Figure 6C The second set of rollers 62 shown includes a third roller 630 and a Figure 5A The first roller 610 is shown. The third roller 630 includes a third forming surface 632 extending between opposite ends 634 of the third roller 630. The first forming surface 612 and the third forming surface 632 are disposed opposite each other. Figure 6C The third forming surface 632 on the third roller 630 is shown extending cylindrically between opposite ends 634. Alternatively, the third forming surface 632 may be slightly convex.

[0100] like Figures 6A to 6C As shown, the polymer material sheet 106 passes through the space between the first forming surface 612 and the second forming surface 622 to obtain a polymer leading edge protection sheet 120 having a chamfered side edge 122. The polymer leading edge protection sheet 120 also passes through the space between the second forming surface 622 and the third forming surface 632, as shown. Figures 6A to 6C shown.

[0101] Typically, the forming surfaces 612, 622, 632 are smooth surfaces. When applying a pressure-sensitive adhesive to the front edge protection sheet 120 after it is produced, it is important to make the contact area as large as possible. This can be achieved by having a flat surface with low roughness on the forming surfaces 612, 622, 632 of the rollers 610, 620, 630.

[0102] Similar to the other rollers 610, 620, 630, Figure 4C The fourth roller 640 is shown to include a fourth forming surface (not shown) extending between opposite ends 644 of the fourth roller 640. Figure 4C In the example shown, the fourth forming surface is positioned opposite the third forming surface 632 on the third roller 630. The fourth forming surface may extend cylindrically between opposite ends 644. Alternatively, the fourth forming surface may be slightly convex. Still alternatively, the fourth forming surface may be concave. The shape of the forming surface depends on the shape of the third forming surface 632 positioned opposite it.

[0103] 7A to 7D A different example of a leading edge protection sheet 120 is shown having chamfered side edges 122. The leading edge protection sheet 120 has a width in the width direction W between the side edges 122 of the polymeric leading edge protection sheet 120. 7A to 7DThe differences between the leading edge protection sheets 120 shown are the thickness T of the leading edge protection sheet 120 at the chamfered side edges 122 compared to the thickness at the central region 124 and the change in profile along the width W.

[0104] like Figure 7A 、 Figure 7C and Figure 7D As shown, the width of the leading edge protection sheet 120 includes a first trisection 131 and a second trisection 132, wherein the first trisection 131 and the second trisection 132 are each located near the side edge 122 corresponding to the first trisection 131 and the second trisection 132. The remaining trisection 133 is arranged between the first trisection 131 and the second trisection 132. The thickness variation of the polymer leading edge protection sheet 120 in the width direction is greater at the first trisection 131 and the second trisection 132, that is, at the side edge 122 than at the remaining trisection 133. This is Figure 7D This is most clearly seen in FIG, where the thickness variation at the third trisection 133 is almost zero.

[0105] The first and second trisections 131 and 132 may have a minimum thickness of less than 0.5 mm, while the remaining trisection 133 may have a maximum thickness of less than 1 mm. The first and second trisections 131 and 132 may have a minimum thickness greater than 0.01 mm, such as greater than 0.05 mm, such as greater than 0.10 mm.

[0106] like Figure 7B As shown, the width of the leading edge protection sheet 120 includes a first quarter 141 and a second quarter 142, wherein the first quarter 141 and the second quarter 142 are each located near the side edge 122 corresponding to the first quarter 141 and the second quarter 142. A remaining half 143 is arranged between the first quarter 141 and the second quarter 142. The thickness variation of the polymer leading edge protection sheet 120 in the width direction is greater in the first quarter 141 and the second quarter 142, that is, at the side edge 122, than in the remaining half 143.

[0107] Figure 8 An alternative system for producing a polymeric leading edge protection sheet 120 having chamfered side edges is shown. Figure 8The illustrated system includes an extrusion system 10, a flat die 50, a roller system 60, a conveyor 70, a quality control section 80, and a pulling roller unit 90. The roller system 60 includes a first pair of rollers 61, which includes a first roller and a second roller 620. The roller system 60 also includes a second pair of rollers 62, which includes a second roller 620 and a third roller 630. The second pair of rollers 62 serves as cooling rollers. The second pair of rollers 62 is controlled by a control unit 64 and a cooling control unit 66, which controls the cooling of the second pair of rollers 62. The quality control section 80 includes a thickness measurement unit 82 for measuring the thickness of the polymer leading edge protection sheet 120. The system also includes a pulling station 84 for pulling the polymer leading edge protection sheet 120 toward the pulling roller unit 90. The pulling roller unit 90 includes a pulling roller 94 and a tension control unit 92 for controlling the tension of the pulling roller unit 90. Figure 8 The illustrated alternative system for producing a polymer leading edge protection sheet 120 having chamfered side edges functions similarly to Figure 1 The functionality of the system has been described in .

[0108] Reference Signs List

[0109] 10Extrusion system

[0110] 20 screen system

[0111] 50 flat mold

[0112] 60-roller system

[0113] 61 first pair of rollers

[0114] 62 second pair of rollers

[0115] 64 Control unit for the second pair of rollers

[0116] 66 Cooling control unit for controlling the cooling of the second pair of rollers

[0117] 70 conveyor

[0118] 80 Quality Control Section

[0119] 82 thickness measurement unit

[0120] 84 Pulling Station

[0121] 90 pull roller unit

[0122] 92 Tension control unit for controlling the tension of the pulling roller unit

[0123] 94 pull roller

[0124] 100 granular polymer materials

[0125] 102 molten polymer material

[0126] 104 Plasticized polymer material

[0127] 106 polymer material sheet

[0128] 108 first main surface

[0129] 110 second main surface

[0130] 120 polymer front edge protection sheet

[0131] 122 chamfered side edges

[0132] 124 Central Area

[0133] 131 First Third Division

[0134] 132 Second and Third Divisions

[0135] 133 The remaining three divisions

[0136] 141 First Quarter Division

[0137] 142 Second Quarter Division

[0138] 143 The remaining half

[0139] 202 Melting the granular polymer material 100 in the extruder process

[0140] 204 The plasticized polymer material 104 is pressed by the flat die 50 to form the plasticized polymer material 104 into a polymer material sheet 106

[0141] 206 Step of providing the polymer material sheet 106 and forming the polymer material sheet 106 into the polymer leading edge protection sheet 120 208 Step of guiding the polymer leading edge protection sheet 120 through a quality control section

[0142] 210 Winding the polymer leading edge protection sheet 120 onto one or more rollers

[0143] 502 Entranceway

[0144] 504 side surface

[0145] 506 flat exit channel

[0146] 508 flat exit channel exit edge

[0147] 510 electric heater

[0148] 610 first roller

[0149] 612 first forming surface

[0150] 614 End of the first roller

[0151] 616 Middle section of the first roller

[0152] 618 end section of the first roller

[0153] 620 second roller

[0154] 622 second forming surface

[0155] 624 End of the second roller

[0156] 630 third roller

[0157] 632 third forming surface

[0158] 634 End of the third roller

[0159] 640 fourth roller

[0160] 644 End of the fourth roller

[0161] LA1 first longitudinal axis length

[0162] LA2 second longitudinal axis length

[0163] LA3 third longitudinal axis length

[0164] W1 first width

[0165] W2 second width

[0166] RC curve radius

Claims

1. A method for producing a polymer leading edge protection sheet (120) having chamfered side edges (122) for a wind turbine blade, the method comprising the following steps: - providing a sheet of polymer material (106) comprising a first major surface (108) and a second major surface (110), each major surface (108, 110) having a width extending in a width direction between side edges of the sheet of polymer material (106), wherein the first major surface (108) and the second major surface (110) are oppositely oriented, wherein the sheet of polymer material (106) has a thickness, - forming (206) the polymer material sheet (106) into a polymer leading edge protection sheet (120) by placing the polymer material sheet (106) between at least one pair of rollers comprising a first roller (610) and a second roller (620), wherein: o The first roller (610) includes at opposite ends (614) of the first roller (610) a first forming surface (612) extending between the opposing ends (614), wherein the first forming surface (612) extends concavely between the opposing ends (614); o the second roller (620) includes a second forming surface (622) extending between opposite ends (624) of the second roller (620); o the first forming surface (612) and the second forming surface (622) are arranged opposite to each other; o During the rotation of the first roller (610) and the second roller (620), the thickness of the polymer material sheet (106) is changed by means of the forming surfaces (612, 622) of the rollers (610, 620) to obtain the polymer leading edge protection sheet (120) with chamfered side edges (122), and the polymer leading edge protection sheet (120) has a reduced thickness at the side edges (122) when compared with the sheet thickness at the central area (124).

2. A method according to any preceding claim, wherein: The method further comprises: - melting (202) the granular polymer material (100) by an extruder process to obtain a molten polymer material (102) having a predetermined hardness, thereby obtaining a plasticized polymer material (104); and - pressing (204) the plasticized polymer material (104) through a flat die (50) to form the plasticized polymer material (104) into the polymer material sheet (106).

3. The method of claim 2, further comprising providing a granular polymer material (100), and drying the granular polymer material (100) to a moisture level of 0.02 wt% or less before melting the granular polymer material (100).

4. A method according to any preceding claim, wherein: The polymer material is a polyurethane thermoplastic material comprising a polyol, a chain extender and an aliphatic isocyanate.

5. A method according to any preceding claim, wherein: The polymer material is a polyurethane material, and wherein the polymer leading edge protection sheet (120) is a polyurethane leading edge protection sheet.

6. The method according to any one of claims 2 to 5, wherein: The polymer material is a polyurethane material, and wherein the granular polyurethane material is an aliphatic thermoplastic polyurethane (TPU) made from a polyol such as a difunctional polyol, a butanediol chain extender, and an aliphatic isocyanate.

7. The method according to any one of claims 2 to 6, wherein: The polymer material is a polyurethane material, and wherein the granular polyurethane material further comprises one or more additives, such as UV absorbers, antioxidants and / or pigments.

8. The method according to any one of claims 2 to 7, wherein: The polymer material is a polyurethane material, and wherein the granular polyurethane material does not contain a release agent.

9. A method according to any preceding claim, wherein: The polymeric leading edge protection sheet (120) is characterized by the following physical properties: - Maximum thickness between 0.8mm and 2.0mm; - a Shore A hardness between 65 and 75, as measured by ISO 868; - when measured using ISO 37 / 1A at 23°C, the elongation is greater than 400 mm; - a sound velocity of less than 1700 m / s as measured by ISO 16810 and ISO 16811; and - Erosion resistance at 150 m / s exceeding 8 hours, as measured by DNV-RP-0171.

10. A method according to any preceding claim, wherein: The polymeric leading edge protection sheet (120) is characterized by the following physical properties: - Maximum thickness between 0.7mm and 2.0mm; - a Shore A hardness between 68 and 78, as measured by ISO 868; - when measured using ISO 37 / 1A at 23°C, the elongation is greater than 400 mm; - a sound velocity of less than 1700 m / s as measured by ISO 16810 and ISO 16811; and - Erosion resistance at 140 m / s exceeding 10 hours, as measured by DNV-RP-0171.

11. A method according to any preceding claim, wherein: The polymer leading edge protection sheet (120) has a Shore A hardness of 78 or less.

12. A method according to any preceding claim, wherein: The polymer leading edge protection sheet (120) has a Shore A hardness of 75 or less.

13. A method according to any preceding claim, wherein: The polymer leading edge protection sheet (120) has a width in the width direction between the side edges (122) of the polymer leading edge protection sheet (120), and the width includes a first trisection (131) and a second trisection (132), wherein the first trisection (131) and the second trisection (132) are each located near the side edges (122) of the polymer leading edge protection sheet (120) corresponding to the first trisection (131) and the second trisection (132), wherein a remaining trisection (133) is arranged between the first trisection (131) and the second trisection (132), and wherein a thickness variation of the polymer leading edge protection sheet (120) in the width direction is greater at the first trisection (131) and the second trisection (132) than at the remaining trisection (133).

14. The method according to claim 13, wherein The remaining three equal parts (133) have a maximum thickness of less than 1 mm.

15. The method according to claim 13 or 14, wherein: The first trisection (131) and the second trisection (132) have a minimum thickness of less than 0.5 mm.

16. A method according to any preceding claim, wherein: The polymer leading edge protection sheet (120) has a width in the width direction between the side edges (122) of the polymer leading edge protection sheet (120), and the width includes a first quarter section (141) and a second quarter section (142), wherein the first quarter section (141) and the second quarter section (142) are each located near the side edges (122) of the polymer leading edge protection sheet (120) corresponding to the first quarter section (141) and the second quarter section (142), wherein a remaining half section (143) is arranged between the first quarter section (141) and the second quarter section (142), and wherein the thickness variation of the polymer leading edge protection sheet (120) in the width direction is greater at the first quarter section (141) and the second quarter section (142) than at the remaining half section (143).

17. A method according to any preceding claim, wherein: The second forming surface (622) of the second roller (620) extends cylindrically between the opposite ends (624).

18. A method according to any preceding claim, wherein: The first roller (610) and the second roller (620) each have a longitudinal axis (LA1, LA2) extending between the opposing ends (614, 624), wherein the longitudinal axes (LA1, LA2) are substantially parallel.

19. A method according to any preceding claim, wherein: The first forming surface (612) of the first roller (610) is curved.

20. A method according to any preceding claim, wherein: The second forming surface (622) of the second roller (620) is smooth.

21. A method according to any preceding claim, wherein: Forming the polymer material sheet (106) into the polymer leading edge protection sheet (120) is achieved by pulling and / or pushing the polymer material sheet (106) through the at least one pair of rollers (610, 620).

22. A method according to any preceding claim, wherein: The polymer material sheet (106) is formed into the polymer leading edge protection sheet (120) by pulling the polymer material sheet (106) through the at least one pair of rollers (610, 620), wherein at least the first roller (610) and / or the second roller (620) pulls the polymer material sheet (106) through the at least one pair of rollers (610, 620).

23. The method according to any one of claims 1 to 20, wherein Forming the polymer material sheet (106) into the polymer leading edge protection sheet (120) is achieved in the following manner: Forming the polymer material sheet into the polymer leading edge protection sheet is achieved by allowing the polymer material sheet (106) to fall into a cavity between the at least one pair of rollers (610, 620).

24. A method according to any preceding claim, wherein: The method also includes positioning the polymeric leading edge protection sheet (120) between a second pair of rollers including a third roller (630) and one of the first roller (610) and the second roller (620).

25. The method according to claim 24, wherein The third roller (630) includes a third forming surface (632) extending between opposite ends (634) of the third roller (630), wherein the third forming surface (632) extends concavely between the opposite ends (634).

26. The method according to claim 24, wherein The third roller (630) includes a third forming surface (632) extending between opposite ends (634) of the third roller (630), wherein the third forming surface (632) extends cylindrically between the opposite ends (634).

27. A method according to any preceding claim, wherein: The first roller (610), the second roller (620) and / or the third roller (630) are cooled.

28. The method of any preceding claim, further comprising providing the polymeric leading edge protection sheet (120) through a quality control section (80), the quality control section (80) ensuring performance specifications / required specifications of the polymeric leading edge protection sheet (120).

29. The method of any preceding claim, further comprising winding the polymeric leading edge protection sheet (120) onto one or more rollers (90) prior to adding adhesive and / or shortening the polymeric leading edge protection sheet (120).

30. A polymer leading edge protection sheet (120) obtainable by the method according to claims 1 to 29.

31. A wind turbine blade having a polymer leading edge protection sheet (120) according to claim 30.

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