Backup board for machining process

Abstract

A backup board for use in a machining process includes a fibrous layer, at least one side of the fibrous layer being provided with a surface layer adhered and laminated thereon, wherein the surface layer is made of a cured paper impregnated with a thermosetting resin. The fibrous layer has a density of about 600˜900 kg/m 3 and includes kenaf fibers adhered together by impregnating a thermosetting adhesive into a fibrous mat of the kenaf fibers, the kenaf fibers having an average length of about 10˜200 mm and an average diameter of about 10˜300 μm.

1 . A backup board for use in a machining process, comprising: 
 a fibrous layer, at least one side of the fibrous layer being provided with a surface layer adhered and laminated thereon,    wherein the surface layer is made of a cured fiber sheet impregnated with a thermosetting resin; and    the fibrous layer has a density of about 600˜900 kg/m 3  and includes kenaf fibers adhered together by impregnating a thermosetting adhesive into a fibrous mat of the kenaf fibers, the kenaf fibers having an average length of about 10˜200 mm and an average diameter of about 10˜300 μm.    
   
   
       2 . The backup board of  claim 1 , wherein the density of the surface layer is about 1000˜1500 kg/m 3 .  
   
   
       3 . The backup board of  claim 1 , wherein the surface layer has a thickness of about 0.05˜0.3 mm.  
   
   
       4 . The backup board of  claim 1 , wherein the thermosetting resin occupies about 40˜60 weight % of the surface layer.  
   
   
       5 . The backup board of  claim 1 , wherein the thermosetting adhesive is a phenolic resin adhesive with average molecular weight of about 400˜700 and including about 10˜40 weight % monomers with a molecular weight of about 90˜200 and about 60˜90 weight % polymers with a molecular weight of about 180˜2000.  
   
   
       6 . The backup board of  claim 1 , wherein the average length and the average diameter of the kenaf fibers are about 15˜80 mm and about 70˜150 μm, respectively.  
   
   
       7 . The backup board of  claim 1 , wherein the density of the fibrous layer is about 700˜850 kg/m 3 .  
   
   
       8 . The backup board of  claim 2 , wherein the surface layer has a thickness of about 0.05˜0.3 mm.  
   
   
       9 . The backup board of  claim 2 , wherein the thermosetting resin occupies about 40˜60 weight % of the surface layer.  
   
   
       10 . The backup board of  claim 2 , wherein the thermosetting adhesive is a phenolic resin adhesive with average molecular weight of about 400˜700 and including about 10˜40 weight % monomers with a molecular weight of about 90˜200 and about 60˜90 weight % polymers with a molecular weight of about 180˜2000.  
   
   
       11 . The backup board of  claim 2 , wherein the average length and the average diameter of the kenaf fibers are about 15˜80 mm and about 70˜150 μm, respectively.  
   
   
       12 . The backup board of  claim 2 , wherein the density of the fibrous layer is about 700˜850 kg/m 3 .