Profiled protective tape for rotor blades of wind turbine generators

Abstract

A multilayer protective tape ( 1 ) for rotor blades of wind energy turbines said tape ( 1 ) having a protective top layer ( 2 ) comprising a polymer film and an adhesive bottom layer ( 3 ), wherein the top layer ( 2 ) has a continuous surface (S) that is outwardly curved or outwardly trapezoidal surface such that the tape ( 1 ) has a cross-sectional profile having an inner section between two lateral sections and wherein the inner section has a thickness (T 1 ) made up by the thickness of the top layer ( 2 ) and adhesive bottom layer ( 3 ) that is greater than the thickness of at least one of the lateral sections (T 1 ,T 2 ) made up by the thickness of the top layer ( 2 ) and adhesive bottom layer ( 3 ) and wherein the thickness (T 1 or T 2 ) of at least one lateral section is at most 600 μm and the thickness of the inner section (T 1 ) is at least 330 μm. Also provided are processes for making profiled tapes and methods for applying the tapes to rotor blades and blades containing protective tapes.

What is claimed is: 
     
         1 . A multilayer protective tape ( 1 ) for rotor blades of wind energy turbines said tape ( 1 ) having a protective top layer ( 2 ) comprising a polymer film and an adhesive bottom layer ( 3 ), wherein the top layer ( 2 ) has a continuous surface (S) that is outwardly curved or outwardly trapezoidal such that the tape ( 1 ) has a cross-sectional profile having an inner section between two lateral sections and wherein the inner section has a thickness (T 1 ) made up by the thickness of the top layer ( 2 ) and adhesive bottom layer ( 3 ) that is greater than the thickness of at least one of the lateral sections (T 1 ,T 2 ) made up by the thickness of the top layer ( 2 ) and adhesive bottom layer ( 3 ) and wherein the thickness (T 1  or T 2 ) of at least one lateral section is at most 600 μm and the thickness of the inner section (T 1 ) is at least 330 μm. 
     
     
         2 . The tape ( 1 ) according to  claim 1  wherein the inner section comprises up to 95% of the width of the tape. 
     
     
         3 . The tape ( 1 ) according to  claim 1 , wherein the cross-sectional profile of the tape is symmetric or non symmetric. 
     
     
         4 . The tape ( 1 ) according to  claim 1 , wherein the adhesive bottom layer ( 3 ) has an upper surface facing the top layer ( 2 ) and a bottom surface opposite thereto and wherein the bottom surface is patterned to comprise a plurality of grooves or dots. 
     
     
         5 . The tape ( 1 ) according to  claim 1 , wherein the adhesive bottom layer ( 3 ) comprises across its thickness at least two adhesive layers of which one adhesive layer comprises a foam adhesive. 
     
     
         6 . The tape ( 1 ) according to  claim 1 , wherein the adhesive layer ( 3 ) is prepared by a wet-in-wet coating process. 
     
     
         7 . The tape ( 1 ) according to  claim 1 , wherein the top layer ( 2 ) is of uniform thickness. 
     
     
         8 . The tape ( 1 ) according to  claim 1 , wherein the top layer ( 2 ) is outwardly curved. 
     
     
         9 . The tape ( 1 ) according to  claim 1 , having a thickness at its inner section (T 1 ) of from 400 μm up to 5,000 μm and a thickness at least one, preferably both lateral sections (T 1 , T 2 ) of up to 350 μm. 
     
     
         10 . The tape ( 1 ) according to  claim 1 , wherein the adhesive layer ( 3 ) comprises an acrylic adhesive. 
     
     
         11 . The tape ( 1 ) according to  claim 1 , wherein the top layer ( 2 ) comprises a polyurethane. 
     
     
         12 . Method of protecting a rotor blade of a wind turbine from erosion comprising providing a protective tape ( 1 ) according to  claim 1 , and adhering it to the rotor blade. 
     
     
         13 . Method of protecting a rotor blade from erosion comprising:
 (i) providing a protective tape ( 1 ) according to  claim 1 , wherein the adhesive bottom layer ( 3 ) has an upper surface facing the top layer ( 2 ) and a bottom surface opposite thereto and wherein the bottom surface is patterned to comprise a plurality of grooves or dots;   (ii) applying a liquid adhesive to the rotor blade, to the patterned bottom surface of the tape or both, and   (iii) attaching the tape to the rotor blade.   
     
     
         14 . A rotor blade comprising around its leading edge a protective tape ( 1 ) according to  claim 1 , wherein the lateral sides of the tape face the trailing edge of the blade. 
     
     
         15 . Process of forming a multilayer tape ( 1 ) comprising:
 (i) providing a substrate ( 4 );   (ii) providing in a coating chamber ( 6 ) a coating knife ( 300 ) having a profiled recess ( 301 ) at its lower end facing the substrate ( 4 ) and which forms a gap ( 401 ) normal to the surface of the substrate ( 4 );   (iii) moving the substrate ( 4 ) relative to the coating knive ( 300 ) in a downstream direction;   (iv) providing to the upstream side of the coating knife ( 300 ) a curable adhesive thereby coating an adhesive layer ( 3 ) onto the substrate ( 4 ) through the gap ( 401 );   (v) providing a polymer film ( 2 ) to the upstream side of the coating knife ( 300 ) and feeding the film ( 2 ) simultaneously with the adhesive layer ( 3 ) through the recess ( 301 ) of the coating knife ( 300 ), wherein the film ( 2 ) is positioned between the recess ( 301 ) and the adhesive layer ( 3 );   (vi) curing the adhesive of the multilayer tape thus obtained, wherein the profiled recess ( 301 ) of the coating knife ( 300 ) and the size of the gap ( 400 ) between the coating knife ( 300 ) and the substrate ( 4 ) define the cross-sectional profile of the tape ( 1 ).