Coated abrasive disc and methods of making and using the same

Abstract

A coated abrasive disc includes a disc backing having an outer circumference. An abrasive layer is disposed on the disc backing. The abrasive layer comprises triangular abrasive platelets secured to a major surface of the disc backing by at least one binder material. The triangular abrasive platelets are disposed at least 70 percent of regularly-spaced points along an arithmetic spiral pattern extending outwardly toward the outer circumference. Each one of the triangular abrasive platelets has respective top and bottom surfaces connected to each other, and separated by, three sidewalls. On a respective basis, one sidewall of at least 90 percent of each of the triangular abrasive platelets disposed facing and proximate to the disc backing, and is lengthwise aligned within 10 degrees of being tangent to the arithmetic spiral pattern. Methods of making and using the coated abrasive disc are also disclosed.

1 . A coated abrasive disc comprising:
 a disc backing having an outer circumference;   an abrasive layer disposed on the disc backing, wherein the abrasive layer comprises triangular abrasive platelets secured to a major surface of the disc backing by at least one binder material, wherein the triangular abrasive platelets are disposed at least 70 percent of regularly-spaced points along an arithmetic spiral pattern extending outwardly toward the outer circumference,   wherein each one of the triangular abrasive platelets has respective top and bottom surfaces connected to each other, and separated by, three sidewalls, and   wherein, on a respective basis, one sidewall of at least 90 percent of each of the triangular abrasive platelets disposed facing and proximate to the disc backing, and is lengthwise aligned within 10 degrees of being tangent to the arithmetic spiral pattern.   
     
     
         2 . The coated abrasive disc of  claim 1 , wherein the triangular abrasive platelets have an average thickness, and wherein the arithmetic spiral pattern has a pitch that is 1.2 to 3 times the average thickness of the triangular abrasive platelets. 
     
     
         3 . The coated abrasive disc of  claim 1 , wherein the abrasive layer further comprises crushed abrasive or non-abrasive particles. 
     
     
         4 . The coated abrasive disc of  claim 1 , wherein the disc backing comprises vulcanized fiber. 
     
     
         5 . The coated abrasive disc of  claim 1 , wherein the abrasive layer comprises a make layer and a size layer disposed over the make layer and the triangular abrasive platelets. 
     
     
         6 . The coated abrasive disc of  claim 1 , wherein the triangular abrasive platelets comprise alpha alumina. 
     
     
         7 . A method of abrading, the method comprising frictionally contacting a portion of the abrasive layer of a coated abrasive disc according to  claim 1  with a substrate, and moving at least one of the substrate and the coated abrasive disc relative to the other to abrade the substrate. 
     
     
         8 . The method of  claim 7 , wherein the substrate comprises a mild steel weld, and wherein the abrasive layer contacts the mild steel weld. 
     
     
         9 . A method of making a coated abrasive disc, the method comprising:
 disposing a curable make layer precursor on a major surface of a disc backing having an outer circumference;   adhering triangular abrasive platelets into the curable make layer precursor, wherein the triangular abrasive platelets are disposed at least 70 percent of regularly-spaced points along an arithmetic spiral pattern extending outwardly toward the outer circumference,   wherein the triangular abrasive platelets comprise triangular abrasive platelets, wherein each one of the triangular abrasive platelets has respective top and bottom surfaces connected to each other, and separated, by three sidewalls, and   wherein, on a respective basis, one sidewall of at least 90 percent of each of the triangular abrasive platelets is entirely disposed proximate the disc backing, and is lengthwise aligned within 10 degrees of being tangent to the arithmetic spiral pattern;   at least partially curing the curable make layer precursor to provide a make layer;   disposing a curable size layer precursor over the make layer and triangular abrasive platelets; and   at least partially curing the curable size layer precursor to provide a size layer.   
     
     
         10 . The method of  claim 9 , wherein the triangular abrasive platelets have an average thickness, and wherein the arithmetic spiral pattern has a pitch that is 1.2 to 3 times the average thickness of the triangular abrasive platelets. 
     
     
         11 . The method of  claim 9 , wherein the abrasive layer further comprises crushed abrasive or non-abrasive particles. 
     
     
         12 . The method of  claim 9 , wherein the disc backing comprises vulcanized fiber. 
     
     
         13 . The method of  claim 9 , wherein the triangular abrasive platelets comprise alpha alumina.