Abrasive article containing shaped abrasive particles

Abstract

An abrasive article comprising a binder and abrasive grits, wherein the abrasive grits comprise abrasive particles having specified shapes. Coated abrasive articles of this invention comprise a backing having at least one layer of abrasive material adhered thereto by means of a binder. A portion of this layer contains abrasive particles having specified shapes. It is preferred that the geometric shape of these abrasive particles be triangular. For triangular-shaped particles, about 35% to about 65% of the particles are oriented with a vertex pointing away from the backing and a base in contact with the binder, with about 35% to about 65% of the particles being oriented with a base pointing away from the backing and a vertex in contact with the binder. It is believed that this configuration brings about the result that the sum of the surface areas of each of the particles in contact with the workpiece remains essentially constant during use, even though the surface area of each individual abrasive particle in contact with the workpiece varies during use. The use of the abrasive particles described herein minimizes the formation of flat surfaces on the cutting regions of the abrasive grits.

What is claimed is: 
     
       1. An abrasive article comprising a binder and abrasive grits, wherein at least 10% by weight of said abrasive grits are abrasive particles, each of said abrasive particles having a front face and a back face, said front face having substantially the same geometric shape as said back face, said faces being separated by the thickness of said particle, the ratio of the length of the shortest facial dimension of said particle to the thickness of said particle being at least .[.1.]. .Iadd.2 .Iaddend.to 1. 
     
     
       2. The article of claim 1, wherein the geometric shape of said abrasive particle is triangular. 
     
     
       3. The article of claim 1, wherein the geometric shape of said abrasive particle is rectangular. 
     
     
       4. The article of claim 1, wherein the geometric shape of said abrasive particle is circular. .[.5. The article of claim 1, wherein the ratio of the length of the shortest facial dimension of said particle to the 
     
     
        thickness of said particle is at least 2 to 1..].6. The article of claim 1, wherein the ratio of the length of the shortest facial dimension of 
     
     
        said particle to the thickness of said particle is at least 5 to 1. 7. The article of claim 1, wherein said abrasive grits further comprise eroable 
     
     
        agglomerates. 8. The article of claim 1, further comprising a backing having at least one layer of said abrasive grits adhered thereto by means 
     
     
        of said binder. 9. A coated abrasive article comprising a backing having at least one layer of abrasive grits adhered thereto by means of a binder, said abrasive grits comprising abrasive particles, each of said abrasive particles having a front face and a back face, said faces being separated by the thickness of said particle, said faces having the geometric shape of a triangle, the thickness of said particle being substantially uniform and being less than the length of the shortest side of said triangle, wherein from about 35% to about 65% of said triangular-shaped particles are oriented with a vertex pointing away from said backing and from about 35% to about 65% of said triangular-shaped particles are oriented such 
     
     
        that a base is pointing away from said backing. 10. The article of claim 9, wherein up to 20% of said triangular-shaped particles have neither a 
     
     
        base nor a vertex pointing away from said backing. 11. The article of 
     
     
        claim 9, wherein said abrasive grits include eroable agglomerates. 12. The 
     
     
        article of claim 9, further including a size coat. 13. The article of 
     
     
        claim 12, further including a supersize coat. 14. A coated abrasive article comprising a backing having at least one layer of abrasive grits adhered thereto by means of a binder, wherein at least 10% by weight of said abrasive grits are abrasive particles, each of said abrasive particles having a front face and a back face, said front face having substantially the same geometric shape as said back face, said faces being separated by the thickness of said particle, the ratio of the length of the shortest facial dimension of said particle to the thickness of said particle being at least .[.1.]. .Iadd.2 .Iaddend.to 1, whereby during the use of said article during abrading, the area of each abrasive particle in contact with the surface of the workpiece continually changes, but the sum of the areas of each abrasive particle in contact with the surface of the 
     
     
        workpiece essentially remains constant. 15. The article of claim 14, wherein said abrasive particles have faces that are in the shape of a triangle, wherein from about 35% to about 65% of said triangular-shaped particles are oriented with their vertices pointing away from said backing and from about 35% to about 65% of said triangular-shaped particles are 
     
     
        oriented such that their bases are pointing away from said backing. 16. The article of claim 14, wherein said abrasive grits further comprise 
     
     
        erodable agglomerates. 17. The article of claim 1, wherein said article is 
     
     
        a bonded abrasive article. 18. The article of claim 1, wherein said 
     
     
        article is a nonwoven abrasive article. 19. The article of claim 1, wherein the thickness of said particles is from about 25 to about 500 
     
     
        micrometers. .Iadd.20.  The article of claim 1, further including diluent grains. .Iaddend..Iadd.21. The article of claim 9, further including diluent grains. .Iaddend..Iadd.22. The article of claim 14, further 
     
     
        including diluent grains. .Iaddend..Iadd.23.  The article of claim 1, wherein said abrasive particles consist essentially of alpha alumina and a nucleating agent selected from the group consisting of alpha ferric oxide, titanium oxides, and chrome oxides. .Iaddend..Iadd.24. The article of claim 9, wherein said abrasive particles consist essentially of alpha alumina and a nucleating agent selected from the group consisting of alpha ferric oxide, titanium oxides, and chrome oxides. .Iaddend..Iadd.25. The article of claim 14, wherein said abrasive particles consist essentially of alpha alumina and a nucleating agent selected from the group consisting of alpha ferric oxide, titanium oxides, and chrome oxides. 
     
     
        .Iaddend..Iadd. 6.  The article of claim 1, wherein said article is coated abrasive article. .Iaddend..Iadd.27. The abrasive article of claim 2, wherein the triangular geometric shape of said abrasive particle is equilateral. .Iaddend.