Extrusion method forming an enhanced property metal polymer composite

• US 7,491,356 B2
• Filed: 11/12/2004
• Issued: 02/17/2009
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Tundra Composites, LLC.
• Original Assignee: Tundra Composites, LLC.
• Inventors: Heikkila, Kurt E.
• Primary Examiner(s): Davis; Robert B
• Application Number:
  US10/988,193
• Publication Number:
  US 20060055077A1
• Time in Patent Office: 1,558 Days
• Field of Search: 264/173.16, 264/211, 264/328.18, 264/349
• US Class Current: 264/173.16
• CPC Class Codes: A01K 95/005 Sinkers not containing lead
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: B29L 2031/22 Hinges , pivots
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: F42B 12/745 the core being made of plastics; Compounds or blends of plastics and other materials, e.g. fillers
• CPC Class Codes: F42B 7/046 Pellets or shot therefor
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof

Abstract

The invention relates to an extrusion method and to an extrudable metal polymer composite having increased density, improved viscoelastic properties, malleability and ductility and thermoplastic extrusion or injection molding properties.

Claims

1. A method to extrude a metal polymer composite, the composite comprising a metal particulate phase and a polymer phase, the method comprising:

(a) combining;

(i) about 96 to 45 volume-% of a metal particulate comprising 5 wt-% or less of particles having a particle size of less than 10 microns, the metal having a density greater than 8 gm-cm<sup>−

3</sup>, in a particulate phase having a particle size distribution having at least 10 wt.-% of particulate within of about 10 to 70 microns, at least 20 wt.-% of the polymer particulate within about 70 to 500 microns, a circularity greater than 13 and an aspect ratio less than 3;

(ii) about 4 to 53 volume-% of a polymer phase; and

(iii) about 0.005 to 3 wt.-% of an interfacial modifier material to form a composite mix; and

(b) extruding the composite mixture at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup> to form an extruded metal polymer composite;

wherein the extruded composite has a density greater than about 7 gm-cm<sup>−

3</sup> and a storage modulus of greater than 300 MPa.

2. The method of claim 1 wherein the extruded metal composite comprises a single polymer source and the interfacial modifier comprises about 0.005 to 0.7 wt.-% of the composite.

3. The method of claim 1 wherein the extruded metal composite comprises polymer blend or alloy and the interfacial modifier comprises about 0.005 to 1 wt.-% of the composite.

4. The method of claim 1 wherein the metal particulate phase comprises tungsten and the polymer comprises a vinyl polymer.

5. The method of claim 1 wherein the metal particulate phase is present in an amount of about 50 to 85 volume-%.

6. The method of claim 1 wherein the polymer phase is a halogen containing polymer having a density of greater than 1.2 gm-cm⁻

3.

7. The method of claim 1 wherein the extruded metal composite comprises a pigment or a dye.

8. The method of claim 1 wherein the metal in the particulate has a density greater than 10 gm-cm⁻

3.

9. The method of claim 1 comprising extruding the composite mixture at a temperature greater than 180°

C. and at a shear rate of about 5 to 500 sec<sup>−

1</sup>.

10. An injection molding process comprising heating a composite to an elevated temperature and injecting that composite into a mold;

wherein the composite comprises a polymer, and a metal particulate coated with an interfacial modifier, with the metal of the particulate having a density greater than 4 gm-cm<sup>−

3</sup> and the interfacial modifier being in an amount between 0.005 and 1 wt.-%.

11. A compression molding process comprising molding a composite under elevated pressure;

wherein the composite comprises a polymer, and metal particulate coated with an interfacial modifier, with the metal of the particulate having a density greater than 4 gm-cm<sup>−

3</sup> and the interfacial modifier being in an amount between 0.005 and 1 wt.-%.

12. A sequential compounding process comprising blending a polymer and metal particulate coated with an interfacial modifier, with the metal of the particulate having a density greater than 4gm-cm⁻

3 and the interfacial modifier being in an amount between 0.005 and 1 wt.-%.

13. A sequential compounding process comprising

a first operation of blending a substantially solvent-free mixture of a polymer and metal particulate coated with an interfacial modifier, with the metal of the particulate having a density greater than 4 gm-cm⁻

3 and the interfacial modifier being in an amount between 0.005 and 1 wt.-%, to form a composite, and

a second operation of extruding or molding an object, wherein the molding is compression molding or injection molding.

14. A sequential compounding process comprising

a first operation of blending solvent, polymer, and metal particulate coated with an interfacial modifier, with the metal of the particulate having a density greater than 4 gm-cm⁻

3 and the interfacial modifier being in an amount between 0.005 and 1 wt.-%, and a second operation of extruding or molding an object, wherein the molding is compression molding or injection molding.

15. The method of claim 14 wherein the object is formed by wetting the metal particulate with solvent and removing the solvent after processing.

16. A sequential compounding process comprising

blending solvent, polymer, and metal particulate coated with an interfacial modifier, with the metal having a density greater than 7 gm-cm⁻

3 and the interfacial modifier being in an amount between 0.005 and 1 wt.-%, followed by a solvent degassing of the composite during the melt portion of mixing.

17. A method of manufacturing a metal polymer composite article comprising:

(a) forming a metal polymer mixture by combining;

(i) a metal particulate, the metal having a density greater than 4 gm-cm<sup>−

3</sup> and an excluded volume of about 13 to about 60 volume-%, the metal particulate comprising a coating of an effective composite forming amount of an interfacial modifier; and

(ii) a polymer phase comprising a polymer in an amount sufficient to substantially occupy excluded volume of the particulate;

(b) blending the metal polymer mixture to form a metal polymer composite blend having a density greater than about 4 gm-cm<sup>−

3</sup> and a storage modulus of greater than 300 MPa; and

(c) shaping the metal polymer composite blend to form a metal polymer composite article.

18. The method of claim 17 wherein the article comprises about 0.005 to 3 wt.-% of the interfacial modifier.

19. The method of claim 17 wherein the polymer is a halogen containing polymer haying a density of greater than 1.2 gm-cm⁻

3.

20. The method of claim 17 wherein the article comprises a pigment or a dye.

21. The method of claim 17 wherein the metal particulate comprises at least 5 wt.-% of the metal with particle size ranging greater than 250 microns.

22. The method of claim 19 wherein the polymer comprises a fluoroelastomer.

23. The method of claim 22 comprising shaping by extruding the mixture at a temperature greater than 180°

C. and at a shear rate of about 5 to 500 sec<sup>−

1</sup>.

24. The method of claim 17, further comprising extruding the blend with a coextrudate comprising a polymer.

25. The method of claim 17, further comprising passing the blend through a shaped die to form a shaped composite.

26. The method of claim 25, wherein the shaped die comprises a shape that forms two shaped composite articles to interlock when pressed together.

27. The method of claim 17 wherein the metal particulate comprises a particle size of greater than 10 microns.

28. The method of claim 17 wherein the blending is performed in an extruder.

29. The method of claim 28 wherein at least 5 wt.-% of the metal particulate comprises a particle size of 10 to 70 microns and at least 5 wt.-% of the metal particulate comprises a particle size of 70 to 250 microns.

30. The method of claim 28 wherein said shaping comprises extruding at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup>.

31. The method of claim 30 comprising shaping the composite article by extruding the metal polymer mixture at a temperature greater than 150°

C. and at a shear rate of about 10 to 300 sec<sup>−

1</sup>.

32. The method of claim 31, where the composite article has significantly reduced wear characteristics.

33. A method of manufacturing a metal polymer composite article comprising:

(a) forming a metal polymer mixture by combining;

(i) a metal particulate comprising stainless steel, the steel having a density greater than 4 gm-cm<sup>−

3</sup> and an excluded volume of about 13 to about 60 volume-%, the metal particulate comprising a coating of an effective composite forming amount of an interfacial modifier; and

(ii) a polymer phase comprising a thermoplastic polymer in an amount sufficient to substantially occupy the excluded volume of the particulate;

(b) blending the metal polymer mixture to form a metal polymer composite having a density greater than about 4 gm-cm<sup>−

3</sup> and a storage modulus of greater than 300 MPa; and

(c) shaping the metal composite to form a metal polymer composite article.

34. The method of claim 33 wherein the metal particulate comprises stainless steel particles and particles of a second metal.

35. The method of claim 33 comprising shaping the mixture by extruding at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup>.

36. The method of claim 33 wherein the composition comprises about 0.005 to 3 wt.-% of the interfacial modifier.

37. The method of claim 35 comprising shaping the mixture by extruding at a temperature greater than 150°

C. and at a shear rate of about 10 to 300 sec<sup>−

1</sup>.

38. The method of claim 37 comprising extruding the mixture at a temperature greater than 180°

C. and at a shear rate of about 5 to 500 sec<sup>−

1</sup>.

39. A method of manufacturing a metal polymer composite article comprising:

(a) forming a metal polymer mixture by combining;

(i) a metal particulate comprising a particle blend of first metal particles and second metal particles, the metal having a density greater than 4 gm-cm<sup>−

3</sup> and an excluded volume of about 13 to about 60 volume-%, the metal particulate comprising a coating of an effective composite forming amount of an interfacial modifier; and

(ii) a polymer phase comprising a thermoplastic polymer in an amount sufficient to substantially occupy the excluded volume of the particulate;

(b) blending the metal polymer mixture to form a metal polymer composite having a density greater than about 4 gm-cm<sup>−

3</sup> and a storage modulus of greater than 300 MPa; and

(c) shaping the metal polymer composite to form a metal polymer composite article.

40. The method of claim 39 wherein the metal particulate comprises a product of separately coating the first metal particles from the second metal particles with interfacial modifier before forming the blend.

41. The method of claim 39 wherein the metal particle composite comprises about 0.005 to 3 wt.-% of the interfacial modifier.

42. The method of claim 39 comprising shaping the metal polymer composite by extruding at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup>.