Abrasive and Method of Fabricating Same

Abstract

The invention relates to an abrasive wherein abrasive grains are embedded in a matrix comprising a non-cellular, particularly non-foamed thermosetting binder for the abrasive grains, and wherein a contact surface covered by abrasive grains is configured for abrasion of a workpiece. In accordance with the invention the matrix is elastically compliant to such an extent that the abrasive grains covering the contact surface are impressed into the matrix during abrasion. The abrasive grains are dispersed in the matrix such that the consumption of the matrix perpendicular to the contact surface covered originally with abrasive grains releases a further contact surface covered with abrasive grains. The abrasive grains are dispersed in the matrix such that they comply with the return force of the matrix both perpendicular and parallel to the corresponding contact surface of the abrasive. The matrix is bonded to a flexible backing. Bonding the matrix to its backing is achieved directly via the binder contained in the matrix.

1 . An abrasive wherein abrasive grains are embedded in a matrix comprising a non-cellular, particularly non-foamed thermosetting binder for the abrasive grains, and wherein a contact surface covered by abrasive grains is configured for abrasion of a workpiece,
 characterized by the combination of the following features:   
     a) the matrix is elastically compliant to such an extent that the abrasive grains covering the contact surface are impressed into the matrix during abrasion; 
     b) the abrasive grains are dispersed in the matrix such that the consumption of the matrix perpendicular to the contact surface covered originally with abrasive grains releases a further contact surface covered with abrasive grains; 
     c) the abrasive grains are dispersed in the matrix such that they comply with the return force of the matrix both perpendicular and parallel to the corresponding contact surface of the abrasive; 
     d) the matrix is bonded to a flexible backing; 
     e) bonding the matrix to its flexible backing is achieved directly via the binder contained in the matrix. 
   
   
       2 . The abrasive as set forth in  claim 1 , characterized in that a binder is termed non-cellular when the density of the binder in the matrix is not lower than 70% of the specific density of the substance of the binder. 
   
   
       3 . The abrasive as set forth in  claim 1 , characterized in that a binder is termed non-cellular when the density of the binder in the matrix is not lower than 85%, preferably 90% of the specific density of the substance of the matrix. 
   
   
       4 . The abrasive as set forth in  claim 1 , characterized in that the binder is termed elastically compliant when the elasticity of the matrix is not less than 35%, preferably 40%. 
   
   
       5 . The abrasive as set forth in  claim 1 , characterized in that the binder is termed elastically compliant when the elasticity of the matrix is not higher than 55%, preferably 50%. 
   
   
       6 . The abrasive as set forth in  claim 1 , characterized in that the binder is termed elastically compliant when the hardness of the matrix is not lower than 40 Shore A, preferably 45 Shore A. 
   
   
       7 . The abrasive as set forth in  claim 1 , characterized in that the binder is termed elastically compliant when the hardness of the matrix is not higher than 75 Shore A, preferably 70 Shore A. 
   
   
       8 . The abrasive as set forth in  claim 1 , characterized in that the binder is termed elastically compliant when the ultimate elongation of the matrix is not lower than 150%, preferably 170%. 
   
   
       9 . The abrasive as set forth in  claim 1 , characterized in that the backing is termed elastically compliant when the flexural rigidity of the backing over a sensing width of 15 mm, with a sensing spacing of 20 mm and an angle of rotation of 15° is not higher than 5000 mN 
   
   
       10 . The abrasive as set forth in  claim 1 , characterized in that the thickness of the matrix perpendicular to the backing is not lower than 200 μm, preferably not lower than 500 μm, most preferably not lower than 1000 μm. 
   
   
       11 . The abrasive as set forth in  claim 1 , characterized in that the thickness of the matrix perpendicular to the backing is not higher than 2500 μm, preferably not higher than 1500 μm. 
   
   
       12 . The abrasive as set forth in  claim 1 , characterized in that in the ratio of the volume percentage of the abrasive grains to that of the binder of the matrix the volume percentage of the abrasive grains is smaller or maximally equals 80 volume %, preferably smaller than or maximally equals 60 volume %. 
   
   
       13 . The abrasive as set forth in  claim 1 , characterized in that in the ratio of the volume percentage of the abrasive grains to that of the binder of the matrix the volume percentage of the abrasive grains is greater than or minimally equals 20 volume %, preferably greater than or minimally equals 40 volume %. 
   
   
       14 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains range in size from 2 μm to 2000 μm preferably 70 μm to 540 μm, most preferably have size P36, P60, P120 and P240 as per the FEPA standard. 
   
   
       15 . The abrasive as set forth in  claim 1 , characterized in that the Shore hardness of the abrasive in the Shore hardness A range is preferably between 60° and 90° Shore A. 
   
   
       16 . The abrasive as set forth in  claim 1 , characterized in that the binder comprises a polyurethane, preferably is made of one such polyurethane. 
   
   
       17 . The abrasive as set forth in  claim 1 , characterized in that the binder comprises a rubber, preferably is made of one such rubber. 
   
   
       18 . The abrasive as set forth in  claim 1 , characterized in that the binder comprises a polysulfide, preferably is made of one such polysulfide. 
   
   
       19 . The abrasive as set forth in  claim 1 , characterized in that the binder comprises a polysulfide, preferably is made of one such polysulfide. 
   
   
       20 . The abrasive as set forth in  claim 1 , characterized in that the binder comprises an acrylate, preferably is made of one such acrylate. 
   
   
       21 . The abrasive as set forth in  claim 1 , characterized in that the binder is filled. 
   
   
       22 . The abrasive as set forth in  claim 1 , characterized in that the matrix contains in addition to the binder at least one filler and/or at least one dyestuff and/or at least one other additive. 
   
   
       23 . The abrasive as set forth in  claim 21 , characterized in that kaoline is provided as the filler. 
   
   
       24 . The abrasive as set forth in  claim 22 , characterized in that at least one foam inhibitor is provided as an additive. 
   
   
       25 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains comprise at least one silicon carbide and/or at least one silicon oxide, preferably consists thereof. 
   
   
       26 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains consist of at least one aluminum oxide and/or at least one aluminum oxide mixed crystal. 
   
   
       27 . The abrasive as set forth in  claim 1 , characterized in that at least a portion of the abrasive grains consists of at least one hardmetal. 
   
   
       28 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains in their array nearest to the backing rest on the backing. 
   
   
       29 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains are homogenously dispersed in the matrix. 
   
   
       30 . The abrasive as set forth in  claim 1 , characterized in that the abrasive grains are arranged in the matrix in several layers over the backing. 
   
   
       31 . The abrasive as set forth in  claim 1 , characterized in that the matrix including its abrasive grains is divided into several matrix bodies dispersed over the same backing with mutual spacing, the matrix bodies having a consistent cross-section preferably in the direction perpendicular to the originally contact surface or backing. 
   
   
       32 . The abrasive as set forth in  claim 31 , characterized in that the matrix bodies have a polygonal cross-section parallel to the backing and are preferably arranged mutually staggered in the abrasion direction. 
   
   
       33 . The abrasive as set forth in  claim 32 , characterized in that the polygonal cross-section is hexagonal and preferably oriented with two comers in or opposing the abrasion direction. 
   
   
       34 . The abrasive as set forth in  claim 31 , characterized in that the matrix bodies a have a circular cross-section parallel to the backing and are arranged mutually staggered preferably in the abrasion direction. 
   
   
       35 . The abrasive as set forth in  claim 1 , characterized in that the backing consists of a woven, knitted fabric, film, filament layer and/or one or more non-regulated layers of fibers such as paper, fiber or a non-woven. 
   
   
       36 . The abrasive as set forth in  claim 35 , characterized in that the backing consists of natural or man-made fibers and/or mixtures thereof. 
   
   
       37 . The abrasive as set forth in  claim 1 , characterized in that the backing is inherently elastically compliant. 
   
   
       38 . The abrasive as set forth in  claim 1 , characterized in that the backing has a quality finish. 
   
   
       39 . The abrasive as set forth in  claim 1 , characterized by a configuration as an endless belt. 
   
   
       40 . The abrasive as set forth in  claim 1 , characterized by a configuration as flat material, preferably strips for oscillating drive. 
   
   
       41 . The abrasive as set forth in  claim 1 , characterized by a configuration as disk or bow for oscillating drive. 
   
   
       42 . The abrasive as set forth in  claim 1 , characterized by a configuration as a disk, segmented abrasive disk, laminated abrasive point or wheel for rotational drive. 
   
   
       43 . The abrasive as set forth in  claim 1 , characterized in that the originally contact surface is patterned at the most in the micro-range. 
   
   
       44 . A method of fabricating an abrasive as set forth in  claim 1 , characterized in that the abrasive grains are firstly admixed in the matrix with a binder still at low viscosity before this mixture is applied to the backing. 
   
   
       45 . The method of fabricating an abrasive as set forth in  claim 1 , characterized in that firstly the binder whilst still of low viscosity is applied to the matrix on the backing and then the abrasive grains so that the abrasive grains sink into the backing whilst the binder is still at a low viscosity. 
   
   
       46 . The method as set forth in  claim 45 , characterized in that the abrasive grains are dispersed on the matrix whilst the binder is still at a low viscosity. 
   
   
       47 . The method as set forth in  claim 45 , characterized in that the abrasive grains are applied to the matrix applied in all prior to the backing in several passes whilst the binder is still at a low viscosity. 
   
   
       48 . The method as set forth in  claim 44 , characterized in that the matrix containing the binder and the abrasive grains are applied to the backing together or separately in a multi-coating process. 
   
   
       49 . The method of fabricating an abrasive as set forth in  claim 31 , particularly as set forth in  claim 44 , characterized in that a masking technique is used when configuring the matrix bodies arranged with mutual spacing on the backing.