Abrasive filaments with improved stiffness and industrial brushes comprising the same and uses thereof

Abstract

Disclosed herein are abrasive filaments with improved stiffness and industrial brushes comprising the same, wherein the abrasive filaments are formed of polyamide compositions comprising, (a) at least one polyamide; (b) about 0.1-1 wt % of at least one linear chain extending compound that has a molecular weight of 1000 Daltons or lower; (c) about 0.1-1 wt % of at least one antioxidant; and (d) about 10-40 wt % of abrasive particles, with the total wt % of all components in the composition totaling to 100 wt %.

What is claimed is: 
     
         1 . An abrasive filament formed of a melt blended polyamide composition, wherein the polyamide composition comprises:
 (i) at least one polyamide;   (ii) 0.1-1 wt % of at least one linear chain extending compound having a molecular weight of 1000 Daltons or lower;   (iii) 0.1-1 wt % of at least one antioxidant; and   (iv) 10-40 wt % of abrasive particles,   with the total wt % of all components is based on the total and totals 100 wt %.   
     
     
         2 . The abrasive filament of  claim 1 , wherein the at least one linear chain extending compound is selected from the group consisting of bis-lactam compounds, bis-oxazoline compounds, bis-oxazine compounds, and combinations of two or more thereof, or preferably, the bis-lactam compounds are selected from the group consisting of N,N′-isophthaloyl bis-caprolactam; N,N′-adipoyl bis-caprolactam; N,N′-terephthaloyl bis-laurolactam; N,N′-isophthaloyl bis-butyrolactam; carbonyl bis-caprolactam; and combinations of two or more thereof, and the bis-oxazoline compounds and bis-oxazine compounds are selected from the group consisting of 2,2′-bis(2-oxazoline); 2,2-bis(4-methyl-2-oxazoline); 2,2′-bis(4-phenyl-2-oxazoline); 2,2′-bis(4-hexyloxazoline); 2,2′-p-phenylene bis(2-oxazoline); 2,2′-m-phenylene bis(2-oxazoline); 2,2′-tetramethylene bis(4,4′-dimethyl-2-oxazoline); the corresponding oxazines; and combinations of two or more thereof, or more preferably, the at least one linear chain extending compound is carbonyl bis-caprolactam. 
     
     
         3 . The abrasive filament of  claim 1 , wherein the at least one linear chain extending compound is present in the polyamide composition at a level of 0.2-0.7 wt %, based on the total weight of the polyamide composition. 
     
     
         4 . The abrasive filament of  claim 1 , wherein the at least one antioxidant is selected from sterically hindered phenols, or preferably, the at least one antioxidant is selected from the group consisting of pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 3,3′,3′,5,5′,5′-hexa-tert-butyl-α,α′,α′-(mesitylene-2,4-,6-triyl)tri-p-cresol; N,N′-hexane-1,6-diylbis(3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)); octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate; and combinations of two or more thereof, or more preferably, the at least one antioxidant is N,N′-hexane-1,6-diylbis(3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)). 
     
     
         5 . The abrasive filament of  claim 4 , wherein the at least one antioxidant is present in the polyamide composition at a level of 0.2-0.7 wt %, based on the total weight of the polyamide composition. 
     
     
         6 . The abrasive filament of  claim 1 , wherein the abrasive particles are selected from the group consisting of organic abrasive particles, inorganic abrasive particles, and combinations thereof, or preferably, the abrasive particles are selected from the group consisting of particles based on aluminum oxides, alpha alumina, silicon carbides, titanium diborides, alumina zirconia, diamond, boron carbide, ceria, aluminum silicates, cubic boron nitride, garnet, silica, pumice, sand, emery, mica, corundum, quartz, and combinations of two or more thereof. 
     
     
         7 . The abrasive filament of  claim 1 , wherein the at least one polyamide is selected from aliphatic polyamides, or preferably, the at least one polyamide is selected from the group consisting of polyamide 4,6; polyamide 6; polyamide 6,6; polyamide 6,10; polyamide 6,12; polyamide 6,13; polyamide 6,14; polyamide 6,15; polyamide 6,16; polyamide 9,10; polyamide 9,12; polyamide 9,13; polyamide 9,14; polyamide 9,15; polyamide 9,36; polyamide 10,10; polyamide 10,12; polyamide 10,13; polyamide 10,14; polyamide 11; polyamide 12; polyamide 12,10; polyamide 12,12; polyamide 12,13; polyamide 12,14; and combinations of two or more thereof, or more preferably, the at least one aliphatic polyamide is selected from polyamide 6,10; polyamide 6,12; and combinations thereof. 
     
     
         8 . The abrasive filament of  claim 1 , wherein the at least one polyamide has a relative viscosity of 2.3-5, or preferably 2.3-4, or more preferably 2.3-3.5. 
     
     
         9 . The abrasive filament of  claim 1 , wherein the at least one polyamide is present in the polyamide composition at a level of 60-90 wt, based on the total weight of the polyamide composition. 
     
     
         10 . The abrasive filament of  claim 1 , wherein the abrasive filament is prepared by a continuous melt spinning process, and wherein the process comprises:
 (i) blending the at least one polyamide, the at least one linear chain extender compound, and the at least one antioxidant into a mixture;   (ii) passing the mixture through an extruder while the abrasive particles are added into the extruder through one or more side feeders; and   (iii) melt spinning the composition that comes out of the extruder into filaments.   
     
     
         11 . The abrasive filament of  claim 1 , wherein the abrasive filament is prepared by a two-step melt spinning process, and wherein the process comprises:
 (i) melt compounding the at least one polyamide, the at least one linear chain extender compound, and the at least one antioxidant into resin pellets;   (ii) passing the resin pellets through an extruder while the abrasive particles are added into the extruder through one or more side feeders; and   (iii) melt spinning the composition that comes out of the extruder into filaments.   
     
     
         12 . An industrial brush comprising a plurality of the abrasive filament of  claim 1 . 
     
     
         13 . The use of the industrial brush of  claim 12  in grinding and/or polishing silicon ingots, stone, or metal parts, or preferably the use in grinding and/or polishing silicon ingots.