Multi-resinous molded articles having integrally bonded graded interfaces

Abstract

Molded articles in the form of grinding/cut-off wheels, drill bits, reamers, knife, blade, etc., having a core section or sections comprising a moldable resin of some intensive property, e.g., hardness, concentration, etc., and a surface layer or rim or section(s) comprising another moldable resin of different magnitude of the same intensive property e.g., hardness, concentration, etc., and abrasive articles selected from one or more of diamond, cubic boron nitride (CBN), alumina, SiC, garnet, and mixtures thereof. The articles are characterized in that a) the resins comprising the sections are miscible and diffusively or convectively mixed; b) a composition ratio of the abrasive articles in the resins is decreased inwardly from a surface of said molded article on a scale of the mesh size of the abrasive and article size; and c) the resins comprising the sections are miscible and diffusively mixed.

1 . An abrasive article, which comprises: 
 a first part comprising a first moldable resin having an intensive property;    a second part being adjacent to the first part forming an interface, said second part comprising a second moldable resin having an intensive property of different magnitude from the first moldable resin,    said second moldable resin being at least partially miscible with the first moldable resin; and wherein    the interface between said first part and said second part being diffuse and graded and varying in the magnitude of the intensive property, on at least a molecular scale, limited only by the scale of the abrasive article.    
     
     
         2 . The abrasive article of  claim 1 , wherein the first and second moldable resins are the same.  
     
     
         4 . The abrasive article of claim  3 , wherein the interface between said first part and said second part being diffuse and graded and varying in the magnitude of the intensive property, on a scale of mesh sizes of said abrasive particles.  
     
     
         5 . The abrasive article of  claim 1 , wherein said first and second moldable resins further comprise abrasive particles selected from one or more of diamond, cubic boron nitride (CBN), alumina, SiC, garnet, and mixtures thereof.  
     
     
         6 . The abrasive article of  claim 5 , wherein said abrasive particles comprise diamond.  
     
     
         7 . The abrasive article of  claim 1 , wherein said first and second moldable resins independently are selected from one of a polyetherimide, bis-maleimide-triazine addition copolymer, polyetheretherketone, polyetherketone, poly(amide-imide) resin, polyphenylene sulfide (PPS) resin, liquid crystal polymers (LCP), aromatic polycarbonate resin, and mixtures thereof.  
     
     
         8 . The abrasive article of  claim 2 , wherein said first and second moldable resins are polyether imides, a reaction product of an organic diamine with an aromatic bis-ether dicarbonyl) or an aromatic bis(ether dicarboxylic acid).  
     
     
         9 . The abrasive article of  claim 1 , wherein said abrasive particles range in size from about −600 mesh to about 20 mesh.  
     
     
         10 . The abrasive article of  claim 1 , wherein said abrasive particles are present in said first and second moldable resins in an amount of up to about 95 vol-%, in random or ordered filling.  
     
     
         11 . The abrasive article of  claim 10 , wherein said abrasive particles are coated with a material selected from the group of metal, metal-oxide, refractory-material, and mixtures thereof.  
     
     
         12 . The abrasive article of  claim 11 , wherein said abrasive particles are coated with one or more of Ni, Cu, Cr, Fe, Co, Sn, W, Ti, an alloy thereof, a carbide thereof, and mixtures thereof.  
     
     
         13 . The abrasive article of claim  3 , wherein said first moldable resin further comprises secondary abrasive particles selected from the group of ceramic boride, nitric oxide, Cu, Fe, Sn, bronze, carbon, silica, alumina, Si, and mixtures thereof.  
     
     
         14 . The abrasive article of  claim 1 , in a form of a grinding/cut-off wheel, a drill bit, a reamer, knife, blade, honing mill, or an endmill.  
     
     
         15 . A molded article, which comprises a gradient composite resinous material containing a polymer resin and abrasive particles having various mesh sizes, and wherein 
 a composition ratio of said abrasive articles changes gradually on a scale of the molded article,    said abrasive articles comprise one or more of diamond, cubic boron nitride (CBN), alumina, SiC, garnet, and mixtures thereof.    
     
     
         16 . The molded article of  claim 15 , wherein a composition ratio of said abrasive articles changes gradually inwardly or outwardly toward said surface of said molded article.  
     
     
         17 . The molded article of  claim 15 , wherein said composition ratio of said abrasive articles changes gradually on a scale of the mesh sizes of the abrasive particles and within said molded article,  
     
     
         18 . The molded article of  claim 15 , wherein said gradient composite resinous material further comprises a filler selected from one of silver, copper, gold, aluminum oxide, magnesium oxide, aluminum nitride, silicon nitride, aluminum hydroxide, a metal coated resin, carbon fiber, graphite, micro-bead, whisker, nanotube-shaped carbon, and mixtures thereof.  
     
     
         19 . The molded article of  claim 18 , wherein a composition ratio of said filler is decreased gradiently toward said surface of said molded article.  
     
     
         20 . A method for forming a cutting element, which method comprises the steps of: 
 introducing into a mold or a press at least two resinous materials having different concentrations of abrasive particles selected from one or more of diamond, cubic boron nitride (CBN), alumina, SiC, garnet, and mixtures thereof;    allowing for controlled convective mixing of the contact surface between the resinous layers;    applying sufficient temperature and pressure on said mold or press such that said resinous materials are at least partially miscible, thus forming an intermediate body having a diffuse interface between said at least two resinous materials which is graded in concentrations of said abrasive particles on at least a molecular scale level; and    machining the intermediate body into a desired shape and size to form said cutting element.