Process and device for bending a sheet of synthetic material filled with alumina trihydrate

Abstract

A process is provided for bending a board in synthetic material filled with more than 20% by weight of alumina trihydrate in a methyl methacrylate matrix: a section of the board is heated so that it can be bent; the section to be bent is bent while holding the convex upper surface of the board such that it does not become elongated. Also provided are a device for implementing such a process, and a bent board obtained by such a process.

1 . A method for bending a synthetic material board filled with more than 20% alumina trihydrate in a methyl methacrylate matrix, the method comprising the steps of: 
 heating a section of the board that is to be bent; and    bending the section of the board to be bent,    wherein during the bending step, the upper surface of the board is held firmly-such that it cannot be elongated during bending.    
   
   
       2 . The method in accordance with  claim 1 , wherein a flexible guide is positioned along the length of the upper surface and that guide is clamped against the upper surface during the bending step such that it does not slip.  
   
   
       3 . The method in accordance with  claim 1 , wherein the board is heated from the underside.  
   
   
       4 . A bending device for bending a synthetic material board filled with more than 20% alumina trihydrate in a methyl methacrylate matrix, by heating a section of the board that is to be bent, and bending the section of the board to be bent, the bending device comprising: 
 systems for clamping the board so that the upper surface of the board is held firmly so as to prevent elongation of its upper surface during bending.    
   
   
       5 . The bending device in accordance with  claim 4 , wherein the systems for clamping the board comprise: 
 a flexible guide; and    a holding means for holding the guide against the upper surface.    
   
   
       6 . The bending device in accordance with  claim 5 , wherein the holding means comprises at least one pair of jaws to clamp the board along the length of an edge of the section to bend, the flexible guide being secured to an upper one of the jaws.  
   
   
       7 . The bending device in accordance with  claim 5 , wherein the holding means comprises a flange against which an edge of the board is intended to abut before the bending step.  
   
   
       8 . The bending device in accordance with  claim 7 , further comprising a bending beam mounted to move between an initial position in which the bending beam is above the guide, and an end-position in which the beam has imparted a bending movement to guide by applying pressure to flange.  
   
   
       9 . The bending device in accordance with  claim 6 , wherein the upper jaw comprises a bearing surface intended to apply against the board, the flexible guide being offset from the bearing surface so as to allow a boss to form along the length of the upper jaw during the bending step.  
   
   
       10 . A bent synthetic material board that is filled with more than 60% alumina trihydrate, the bent board being obtained by performing the steps of: 
 heating a section of the board that is to be bent; and    bending the section of the board to be bent,    wherein during the bending step, the upper surface of the board is held firmly such that it cannot be elongated during bending.    
   
   
       11 . The bent board in accordance with  claim 10 , wherein the bend radius of the underside surface is between one and four times the thickness of the board.  
   
   
       12 . The bent board in accordance with  claim 10 , wherein the board is a board in Corian™.  
   
   
       13 . The bent board in accordance with  claim 12 , wherein the bend radius of the underside surface is between one and four times the thickness of the board.