SHAPED ABRASIVE PARTICLES AND METHODS OF FORMING SAME

• US 20160326416A1
• Filed: 07/19/2016
• Published: 11/10/2016
• Est. Priority Date: 05/23/2012
• Status: Active Grant

• Current Assignee: Saint-Gobain Ceramics & Plastics Incorporated (Compagnie De Saint-Gobain)
• Original Assignee: Saint-Gobain Ceramics & Plastics Incorporated (Compagnie De Saint-Gobain)
• Inventors: Bauer, Ralph, Barnes, Martin, Demers, Rene G., Skowron, Margaret L.
• Granted Patent: US 9,688,893 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01J 2/20 by expressing the material, e.g. through sieves and fragmenting the extruded length
• CPC Class Codes: B01J 2/22 by pressing in moulds or between rollers
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/6021 Extrusion moulding
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 35/624 Sol-gel processing
• CPC Class Codes: C09K 3/1409 Abrasive particles per se preparation of diamond C01B32/25
• CPC Class Codes: C09K 3/1427 obtained by division of a mass agglomerated by melting, at least partially, e.g. with a binder
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

A method of forming a shaped abrasive particle includes applying a mixture into a shaping assembly within an application zone and directing an ejection material at the mixture in the shaping assembly under a predetermined force, removing the mixture from the shaping assembly and forming a precursor shaped abrasive particle.

Claims

1. A shaped abrasive particle having a body comprising an arrowhead shape.

2. The shaped abrasive particle of claim 1, wherein the body comprises a first major surface, a second major surface, and a first surface joining the first major surface and second major surface, wherein at least a portion of the side surface comprises a concave curvature.

3. The shaped abrasive particle of claim 2, wherein the second major surface is substantially planar.

4. The shaped abrasive particle of claim 2, wherein the first major surface is substantially planar.

5. The shaped abrasive particle of claim 1, wherein the body comprises a tortuous contour.

6. The shaped abrasive particle of claim 1, wherein the body comprises a percent flashing of not greater than about 10%.

7. The shaped abrasive particle of claim 1, wherein the body comprises a length (l), a width (w), and a height (hi), wherein the height (hi) is an interior height of the body and wherein the width>

length, wherein the length>

height, wherein the width>

height.

8. The shaped abrasive particle of claim 1, wherein the a body comprises a dishing value (d) of not greater than about 2.

9. The shaped abrasive particle of claim 1, wherein the body comprises a first side surface, a second side surface, and a third side surface, wherein the first side surface extends into a volume of the body, and wherein the second side surface and the third side surface are substantially planar.

10. The shaped abrasive particle of claim 1, wherein a side surface of the body comprises a fractured region.

11. The shaped abrasive particle of claim 10, wherein the fractured region has a surface roughness greater than a surface roughness of a first major surface of the body.

12. The shaped abrasive particle of claim 10, wherein the fractured region defines a portion of the body extending from the base surface, and wherein the fractured region defines a serrated edge.

13. The shaped abrasive particle of claim 10, wherein the fractured region defines at least a portion of a side surface extending into a volume of the body.

14. A method comprising:

forming a precursor shaped abrasive particle in less than about 18 minutes, wherein forming comprises;

applying a mixture into a shaping assembly within an application zone; and

removing the mixture from the shaping assembly to form a precursor shaped abrasive particle.

15. The method of claim 14, wherein the mixture comprises a gel comprising a ceramic powder material as an integrated network of discrete particles.

16. The method of claim 14, wherein the mixture comprises an amount of a ceramic material of at least about 145 wt % for the total weight of the mixture.

17. The method of claim 14, wherein the mixture comprises an amount of a liquid of at least about 140 wt % for the total weight of the mixture.

18. The method of claim 14, wherein the mixture comprises not greater than about 30 wt % organic materials for the total weight of the mixture.

19. The method of claim 14, wherein the mixture comprises a storage modulus of at least about 1×

104 Pa.

20. The method of claim 14, wherein the mixture comprises a viscosity of at least about 1×

104 Pa s.

21. The method of claim 14, wherein the mixture comprises a ceramic material selected from the group consisting of an oxide, a nitride, a carbide, a boride, an oxycarbide, oxynitride, and a combination thereof.

22. The method of claim 14, wherein applying comprises extruding the mixture through a die opening and into the shaping assembly.

23. The method of claim 22, wherein extruding is conducted at a pressure of at least about 10 kPa.

24. The method of claim 22, wherein extruding is conducted at a pressure of not greater than about 10,000 kPa.

25. The method of claim 14, wherein the shaping assembly comprises an opening configured to receive the mixture and defined by at least three surfaces.

26. The method of claim 14, wherein the shaping assembly comprises a first portion comprising a screen and a second portion comprising a backing plate, wherein the first portion and the second portion are adjacent to each other in the application zone.

27. The method of claim 26, wherein a surface of the backing plate is configured to contact the mixture in the opening of the screen.

28. The method of claim 14, wherein an angle between the direction of translation of the screen and a direction of extrusion is substantially orthogonal.

29. The method of claim 14, wherein at least a portion of the shaping assembly is translated through the application zone.

30. The method of claim 29, wherein the portion of the shaping assembly is translated at a rate of at least about 0.5 mm/sec.

31. The method of claim 14, wherein applying the mixture comprises extruding the mixture through a die opening and into an opening in the shaping assembly, wherein during extrusion into the opening, the mixture flows into a first portion of the shaping assembly and abuts a surface of a second portion of the shaping assembly.

32. The method of claim 14, further comprising translating at least a portion of the shaping assembly from the application zone to an ejection zone.

33. The method of claim 32, wherein the shaping assembly comprises a backing plate, and the backing plate is removed in the ejection zone.

34. The method of claim 32, wherein opposing major surfaces of the mixture are exposed in an opening of a portion of the shaping assembly in the ejection zone.

35. The method of claim 14, further comprising removing the mixture from at least one surface of a portion of the shaping assembly prior to removing the mixture from the shaping assembly.

36. The method of claim 14, wherein removing the mixture comprises directing an ejection material at the mixture in the shaping assembly under a predetermined force, removing the mixture from the shaping assembly and forming a precursor shaped abrasive particle.

37. The method of claim 14, wherein the ejection material directly contacts an exposed major surface of the mixture in an opening of the shaping assembly.

38. The method of claim 14, wherein the mixture comprises a change in weight of less than about 5% for a total weight of the mixture for a duration the mixture is in an opening of the shaping assembly.

39. The method of claim 38, wherein the mixture has essentially no change in weight for the duration the mixture is in the opening.

40. The method of claim 14, wherein the mixture comprises a change in volume of less than about 5% for a total volume of the mixture for a duration the mixture is in an opening of the shaping assembly.

41. The method of claim 40, wherein the mixture has essentially no change in volume for the duration the mixture is in the opening.

42. The method of claim 14, wherein an average residence time of the mixture in an opening of the shaping assembly is less than about 18 minutes.

43. The method of claim 14, wherein an average residence time of the mixture in an opening of the shaping assembly is less than about 20 seconds.

44. The method of claim 14, wherein removing the mixture includes directing an ejection material at the mixture in the shaping assembly under a predetermined force of at least about 0.1 N.

45. The method of claim 14, wherein the predetermined forced is not greater than about 500 N.

46. The method of claim 44, wherein the ejection material comprises a fluidized material comprises a liquid, a gas, and a combination thereof.

47. The method of claim 44, wherein the ejection material comprises a fluidized material consisting essentially of air.

48. The method of claim 44, wherein the ejection material comprises an additive including a material selected from the group of materials consisting of an organic material, an inorganic material, and a combination thereof.

49. The method of claim 44, wherein directing the ejection material at the mixture is conducted at a temperature of not greater than about 300°

C.

50. The method of claim 49, wherein directing the ejection material at the mixture is conducted at a temperature of at least about 15°

C.

51. The method of claim 14, wherein an opening in the shaping assembly comprises a two dimensional shape as viewed in a plane defined by the length and the width of the screen selected from the group consisting of polygons, ellipsoids, numerals, Greek alphabet characters, Latin alphabet characters, Russian alphabet characters, Arabic alphabet characters, complex shapes having a combination of polygonal shapes, and a combination thereof.

52. The method of claim 14, wherein the precursor shaped abrasive particle has a two-dimensional shape substantially corresponding to a two-dimensional shape of an opening in the shaping assembly.

53. The method of claim 14, wherein a surface of a portion of the shaping assembly comprises a coating including a fluorinated polymer.

54. The method of claim 14, wherein the mixture comprises a coil value of at least about 1800N.

55. The method of claim 14, wherein the mixture experiences a change in temperature of not greater than about 10°

C. in a duration between applying the mixture into the shaping assembly and removing the mixture from the shaping assembly.

56. The method of claim 14, wherein forming a precursor shaped abrasive particle comprises essentially no change in temperature of the mixture in the shaping assembly.

57. The method of claim 14, wherein the mixture is translated at least about 0.2 m in the shaping assembly between the application zone and an ejection zone.

58. The method of claim 14, wherein further comprising forming a batch of precursor shaped abrasive particles having a weight of not less than about 1 kg in not greater than about 30 minutes.

59. The method of claim 14, wherein applying is conducted at a rate of at least about 1 m/min.

60. The method of claim 14, wherein the shaping assembly is in the form of a belt having a length of not greater about 1 meter.