Abrasive medium comprising a phosphate-based filler

Abstract

The invention relates to an abrasive medium which is bonded with a thermosetting material and comprises abrasive particles, a thermosetting binder and optionally further fillers, and contains a phosphate-based additive, the percentage of the phosphate-based additive being 1 to 10 wt.-% of the starting mixture of the abrasive medium. The phosphate-based additive is homogeneously distributed in the abrasive medium. The invention also relates to a method for producing corresponding thermosetting resin-bonded grinding disks.

1 . An abrasive medium bonded with a thermosetting material comprising abrasive particles, thermosetting binder, and optionally further fillers,
 characterized in that   the abrasive medium contains a phosphate-based additive, wherein the proportion of the phosphate-based additive is 1 to 10 wt. % of the starting mixture of the abrasive medium and wherein the phosphate-based additive is distributed homogeneously in the abrasive medium.   
     
     
         2 . An abrasive medium according to  claim 1 , wherein the proportion of the phosphate-based additive in the starting mixture of the abrasive medium is 1 to 5 wt. %. 
     
     
         3 . An abrasive medium according to  claim 1 , wherein the phosphate-based additive is phosphates of alkaline-earth metals. 
     
     
         4 . An abrasive medium according to  claim 1 , wherein the phosphate-based additive is a calcium phosphate. 
     
     
         5 . An abrasive medium according to  claim 1 , wherein the phosphate-based additive is insoluble in water. 
     
     
         6 . An abrasive medium according to  claim 1 , wherein the binder is phenolic resin or modified phenolic resin. 
     
     
         7 . An abrasive medium according to  claim 1 , wherein the proportion of the binder is 1 to 40 wt. %. 
     
     
         8 . An abrasive medium according to  claim 1 , wherein the abrasive medium is a grinding wheel or a coated abrasive. 
     
     
         9 . A method of producing a grinding wheel bonded with a thermosetting material, which comprises the following steps:
 preparing a pulverulent phosphate-based additive, wherein the proportion of the phosphate-based additive is 1 to 10 wt. % of the starting mixture of the grinding wheel,   mixing the pulverulent phosphate-based additive with abrasive particles, binder and optionally further fillers, with the result that the phosphate-based additive is distributed homogeneously in the starting mixture;   pouring the starting mixture into a mould;   adding glass fabric;   pressing the mixture to form a green compact;   curing the green compact to obtain a grinding wheel.   
     
     
         10 . The method for producing a grinding wheel according to  claim 9 , wherein the pulverulent phosphate-based additive is first mixed with the abrasive particles and this mixture is then combined with the binder and optionally further fillers. 
     
     
         11 . The abrasive medium according to  claim 1 , wherein the proportion of the phosphate-based additive in the starting mixture of the abrasive medium is approximately 4 wt. %. 
     
     
         12 . The abrasive medium according to  claim 3 , wherein the phosphate-based additive is magnesium, calcium, strontium or barium phosphates, iron(II) phosphates, iron(III) phosphates, manganese, aluminium or zinc phosphate, synthetic or mineral phosphates, or mixtures thereof. 
     
     
         13 . The abrasive medium according to  claim 4 , wherein the phosphate-based additive is dicalcium phosphate, tricalcium phosphate, hydroxylapatite, fluorapatite, dimagnesium phosphate, trimagnesium phosphate, magnesium diphosphate or mixtures thereof. 
     
     
         14 . The abrasive medium according to  claim 1 , wherein the proportion of the binder is 5 to 30 wt. % of the starting mixture of the abrasive medium. 
     
     
         15 . The abrasive medium according to  claim 14  wherein the proportion of the binder is 10 to 20 wt. % of the starting mixture of the abrasive medium.