Abrasive composition and articles incorporating same

In an abrasive-loaded device suitable for being removably mounted on a tool, the device having a shaped body of elastomeric material having dispersed therein an effective amount of abrasive particles, said shaped body being suitable for grinding, deburring, finishing and sanding, and having means for removably mounting said shaped body on a tool, the elastomeric material comprising a smear-resistant and wear-resistant elastomeric polyurea binder matrix having urea linkages, the binder matrix selected from the group consisting of:

• (1) the reaction product of a first polyfunctional amine having an average functionality of 2 and an equivalent weight of at least about 300, said first polyfunctional amine being capable on polymerization of forming a first soft segment, and a polyfunctional isocyanate having an average isocyanate functionality of at least 2 and an equivalent weight of less than about 300, said polyfunctional-isocyanate being capable of polymerization of forming a first segment, and
• (2) the reaction product of a polyfunctional isocyanate prepolymer having a functionality of at least 2 and having an equivalent weight of at least about 300, said polyfunctional isocyanate prepolymer being capable on polymerization of forming a second soft segment, and a second polyfunctional amine having an average functionality of at least 2 and an equivalent weight of less than about 300, said second polyfunctional amine being capable on polymerization of forming a second hard segment.

A method of making a bonded abrasive composition, said method comprising the steps of:

• (a) combining the reaction precursors of a smear-resistant elastomeric polyurea binder matrix, the binder matrix selected from the group consisting of
• 1) the reaction product of a first polyfunctional amine having an average functionality of 2 and an equivalent weight of at least about 300, said first polyfunctional amine being capable on polymerization of forming a first soft segment, and a polyfunctional isocyanate having an average isocyanate functionality of at least 2 and an equivalent weight of less than about 300, said polyfunctional isocyanate being capable on polymerization of forming a first hard segment;
• and
• 2) the reaction product of a polyfunctional isocyanate prepolymer having a functionality of at least 2 and having an equivalent weight of at least about 300, said polyfunctional isocyanate prepolymer being capable on polymerization of forming a second soft segment, and a second polyfunctional amine having an average functionality of at least 2 and an equivalent weight of less than about 300, said second polyfunctional amine being capable on polymerization of forming a second hard segment;
• with an effective amount of abrasive particles to form a curable abrasive mixture;
• and
• (b) curing the mixture to form said bonded abrasive composition.

An abrasive article comprising:

• (A) a bonded abrasive composition comprising:
• 1) a cured smear-resistant and wear-resistant elastomeric polyurea binder matrix having urea linkages, the binder matrix selected from the group consisting of;
• a) the reaction product of a first polyfunctional amine having an average functionality of 2 and an equivalent weight of at least about 300, said first polyfunctional amine being capable on polymerization of forming a first soft segment, and a polyfunctional isocyanate having an average isocyanate functionality of at least 2 and an equivalent weight of less than about 300, said poly functional isocyanate being capable on polymerization of forming a first hard segment;
• and
• b) the reaction product of a polyfunctional isocyanate prepolymer having a functionality of at least 2 and having an equivalent weight of at least about 300, said polyfunctional isocyanate prepolymer being capable on polymerization of forming a second soft segment, and a second polyfunctional amine having an average functionality of at least 2 and an equivalent weight of less than about 300, said second polyfunctional amine being capable on polymerization of forming a second hard segment;
• and,
• 2) an effective amount of abrasive particles dispersed throughout said binder matrix,
• said composition integrally molded to a backing comprising
• B) a tough, heat resistant, thermoplastic binder material and an effective amount of a fibrous reinforcing material distributed throughout the tough, heat resistant, thermoplastic binder material;
• wherein the tough, heat resistant, thermoplastic binder material and fibrous reinforcing material together comprise a hardened composition that will not substantially deform or disintegrate under abrading conditions.